Honeywell Weather Radio T775J User Manual

T775J  
Electronic Remote Temperature Controller  
PRODUCT DATA  
FEATURES  
T775 model provides reset control with two  
temperature inputs and one of either 4 to 20 mA, 0 to  
18 Vdc, or Electronic Series 90a Proportional + Integral  
modulating output with 0 or 1 relay output stages, or 1  
or 2 relay output stages with no modulation.  
-40°F to +220°F (-40°C to +105°C) setpoint temperature  
range.  
-45°F to +225°F (-43°C to +107°C) sensor display  
range.  
-30°F to + 140°F (-34°C to +60°C) ambient temperature  
range.  
Linear platinum temperature sensor.  
Adjustable temperature range and differential.  
Adjustable throttling range of 2° to 30° F or C.  
Adjustable reset ratio.  
Liquid crystal display (LCD) indication for mode and  
output status.  
Keypad provides ease of programming and  
operation.  
Accuracy is within +/- 1°F/C at nominal input voltage,  
nominal sensor ambient temperature (77°F (25°C)  
operating ambient). Accuracy can vary as parameters  
deviate from nominal.  
Stages independently programmed for heating or  
cooling.  
24/120/240 Vac voltage inputs.  
Spdt relay outputs.  
GENERAL  
The T775J family of electronic remote temperature controllers  
provides reset control for chillers, heating and cooling  
systems, and other applications where electronic accuracy in  
addition to remote sensing is desired.  
IMPORTANT  
The T775 is an operating control, not a limit or safety  
control. When used in applications requiring safety  
or limit controls, use a separate safety or limit control  
device in conjunction with the T775.  
a
The Electronic Series 90 output provided with T775J  
models will not drive electromechanical Series 90 slidewire  
devices.  
Contents  
General ...............................................................................  
1
1
2
2
3
Features ..............................................................................  
Specifications ......................................................................  
Ordering Information ...........................................................  
Installation ...........................................................................  
Description/Operation ......................................................... 13  
Checkout ............................................................................. 18  
Copyright © 1995 Honeywell Inc.  
All Rights Reserved  
63-2248-4  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
Mounting:  
Mounts on any suitable horizontal or vertical surface. (See  
Fig. 5 for mounting hole locations.)  
CAUTION  
Disconnect power before installation to prevent  
electrical shock or equipment damage.  
Dimensions:  
See Fig. 1.  
Location and Mounting  
Display Resolution:  
Sensed temperature and other operating parameters are  
Mount the controller in any convenient interior location using  
the two mounting holes provided. Mounting screws are not  
displayed via a liquid crystal display (LCD) with a resolution of  
included. Use controller dimensions in Fig. 1 as a guide.  
1°F or 1°C.  
Sensor Location  
Accessories:  
The 193987GA Sensor can be used up to 1000 ft (304m)  
from the T775 using standard AWG 18/2 unshielded wire. If  
longer than 25 feet in an electrically noisy environment, use  
shielded cable. Locate the sensor on pipes, in immersion  
wells, in wall-mounted cases or on a bulb holder.  
C7100C1003 Duct Mount Averaging Sensor*.  
T7047C1090 Wall Mount Sensor Case.  
107324A Bulb Holder, duct insertion.  
121371A Copper Immersion Well.  
121371E Stainless Steel Immersion Well.  
107408 Heat Conduction Compound, 4 ounce.  
C7043A1098 Case and Immersion Well.  
203401B Waterproof Sensor.  
Multiple sensors can be parallel-series wired to sense  
average temperature in large spaces. In order to maintain  
control accuracy, be sure the number of sensors parallel-  
series wired is of the n2 power (i.e., 1, 4, 9, 16, etc). See  
Fig. 2.  
203531A Panel Mounting Kit.  
A775A1003 Sensor Simulator.  
*Use of C7100C1003 decreases accuracy of T775 to ±2°F  
(±1°C).  
SENSORS  
SET  
SELECT  
ENTER  
8-1/2  
(216)  
5-7/32  
(134)  
1-1/4  
(32)  
1-1/4  
(32)  
3-13/16 (97)  
4-3/4 (121)  
TO T775 CONNECTIONS 1 AND 2 (SENSOR A)  
2-3/8 (60)  
OR 7 AND 8 (SENSOR B).  
M7431  
M344C  
7/8 (22) DIAMETER  
Fig. 2. Parallel-series wiring of sensors.  
Fig. 1. Approximate T775J dimensions in in. (mm).  
Sensor Mounting  
Mount the sensor on a wall or panel for sensing space  
temperature (Fig. 3); strap it to a pipe, or insert it into a well  
(Fig. 4) for hot/cold water sensing; or tape it to a standard  
cap or bulb holder for duct air sensing. To prevent moisture or  
condensation entering the sensor through the leadwire holes,  
mount the sensor with leadwires exiting the bottom of the  
sensor.  
INSTALLATION  
When Installing this Product...  
³ Read these instructions carefully. Failure to follow them  
could damage the product or cause a hazardous  
condition.  
· Check the ratings given in these instructions and on the  
product to make sure the product is suitable for your  
application.  
NOTE: Use heat conductive compound in immersion wells.  
See Accessories.  
» Installer must be a trained, experienced service  
technician.  
¿ After installation is complete, check out the product  
operation as provided in these instructions.  
3
63-2248—4  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
Mounting Sensor in T7047C1090 Case  
Wiring  
³ Run wires from T775J through wall.  
· Mount case to wall with screws provided.  
» Connect wires from the T775J to two T terminals on the  
T7047C Case.  
CAUTION  
Disconnect external power before wiring to prevent  
electrical shock or equipment damage.  
Cut and strip 193987GA Sensor leads to 3 to 4 inch (76  
to 102 mm) length and connect to T terminals in the  
case.  
Position sensor as shown in Fig. 3; assemble cover and  
tighten cover screws.  
IMPORTANT  
The T775J is not intended for safety limit  
applications. It is an operating control, not a safety  
control.  
CAUTION  
Disconnect external power before wiring to prevent electrical  
shock or equipment damage. All wiring must comply with  
applicable local codes and ordinances.  
1. Make sure that metal tube of sensor does not short  
against T terminals in wall-mounted case.  
2. Do not run sensor wiring (even if using shielded  
cable) with building power wiring.  
Refer to Fig. 4 for locating the appropriate power inputs,  
remote sensor inputs, relay, modulating output terminals,  
contact closure input, and sensor selection switch. Access the  
terminals through standard conduit knockouts (A-C) located  
around the enclosure perimeter.  
T7047C1090  
WALLMOUNT SENSOR  
CASE (OPTIONAL)  
193987GA  
SENSOR  
LEADWIRES  
TO T775  
NOTE: Hole A should only be used for remote sensor  
wiring, low voltage wiring, and access to modulating  
output.  
SCREW  
TERMINAL  
When wiring the input power, only one source of power can  
be applied to the T775J (e.g., 24 or 120 or 240 Vac).  
Knockouts B and C can be used to gain access to 120 or 240  
Vac input terminals and the load relay output terminals.  
SCREW  
TERMINAL  
The T775J can be used to provide reset control of damper  
and valve actuators that accept 4 to 20 mA, 0 to 18 Vdc or  
Electronic Series 90 modulating inputs, and to control one on-  
off load. Depending on the application and the motor or  
actuator used, the T775J can control up to three Modutrol  
motors by using resistor kits that are available as accessories  
for existing motors. Use specified resistor kits to control an  
Electronic Series 90 (Modutrol®) Motor with a 4 to 20 mA  
controller. Obtain information on these kits from either the  
TRADELINE® catalog, motor specification or your local  
distributors. See Fig. 7 through 15 for typical T775J wiring and  
applications.  
CAUTION: POSITION SENSOR AWAY  
FROM SCREW TERMINALS.  
M8109C  
Fig. 3. Sensor mounted on wall.  
COVER SENSOR  
LEADS WITH  
HEAT CONDUCTIVE  
COMPOUND  
SENSOR PLACED  
IN WELL  
1/2 NPT  
IMMERSION  
WELL  
M5249  
Fig. 4. Sensor inserted in immersion well.  
63-2248—4  
4
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
LCD  
TEMPERATURE  
DISPLAY  
C/F  
OC / OF SELECTION  
PROGRAMMING  
KEYS  
SET  
ENTER  
SELECT  
SENSOR INPUT,  
TOD, AND  
24V TERMINALS  
RESET DIP  
SWITCHES  
SA SB  
MOUNTING  
HOLE  
2
3
5
1
4
6
7
8
LOCATION  
SA TOD 24V SB  
KNOCKOUT "A"  
3
2
1
MODULATING OUTPUT  
ELECTRONIC  
SERIES 90, 4-20 mA  
OR 0-18 VDC  
DEPENDING ON MODEL  
LINE  
VOLTAGE  
INPUTS  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NO COMNC  
KNOCKOUT "C"  
M8118  
KNOCKOUT "B"  
RELAY OUTPUT  
STAGES  
Fig. 5. Feature locations.  
IMPORTANT  
T775  
Erratic temperature readings from the 193987GA  
Sensor can be caused by poor wiring practices that  
must be avoided to assure proper operation:  
a. Do not route temperature sensor wiring with  
building power wiring.  
C/F  
SET  
ENTER  
SELECT  
b. Do not locate temperature sensor wiring next to  
control contactors.  
c. Do not locate temperature sensor wiring near  
electric motors.  
d. Do not locate temperature sensor wiring near  
welding equipment.  
e. Make sure good mechanical connections are  
made to both the sensor and the controller.  
f. Do not mount sensor with leadwire end (wire end)  
pointing up in an area where condensation can  
occur.  
GROUND  
SHIELD  
TO T775  
CASE OR TO  
GROUNDING  
SCREW  
SA SB  
2
3
5
1
4
6
7
8
SHIELDED  
CABLE  
SA TOD 24V SB  
3
2
1
g. Use shielded wiring to connect the sensor to the  
T775 when an electrically noisy environment  
exists. See Fig. 6.  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NO COMNC  
SHIELDED  
CABLE  
NOTE: DO NOT GROUND  
GROUNDING SCREW  
SHIELDED CABLE AT  
SENSOR END.  
SENSOR  
NOTE: TO MINIMIZE NOISE PICKUP, MAKE CONNECTION  
FROM SHIELDED CABLE AS CLOSE AS POSSIBLE  
TO SENSOR BODY.  
M4718  
Fig. 6. Using shielded cable for cable  
runs longer than 25 feet.  
5
63-2248—4  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
C/F  
C/F  
SET  
ENTER  
SELECT  
SA SB  
SET  
ENTER  
SELECT  
SA SB  
SENSOR A  
SENSOR B  
2
3
5
1
4
6
7
8
SA TOD 24V SB  
1
3
2
SENSOR A  
24 VAC  
SENSOR B  
2
3
5
1
4
6
7
8
SA TOD 24V SB  
3
2
1
BLK  
240 VAC  
RED  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NO COMNC  
LOAD 1  
LOAD 2  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NO COMNC  
LOAD 1  
M8111  
LOAD 2  
M8113  
Fig. 7. Reset control with 24 Vac input,  
24 Vac loads.  
Fig. 9. Reset control with 240 Vac input, 240 Vac loads.  
C/F  
C/F  
SET  
SET  
ENTER  
ENTER  
SELECT  
SELECT  
SA SB  
SA SB  
SENSOR A  
SENSOR B  
SENSOR A  
SENSOR B  
2
3
5
2
3
5
1
4
6
7
8
1
4
6
7
8
SA TOD 24V SB  
SA TOD 24V SB  
3
2
1
3
2
1
BLK  
BLK  
120 VAC  
WHT  
120 VAC  
WHT  
OUTPUT 1  
NO COM NC  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NO COMNC  
OUTPUT 2  
NO COMNC  
LOAD 1  
LOAD 1  
24 VAC  
LOAD 2  
LOAD 2  
M8114  
M8112  
Fig. 10. Reset control with 120 Vac input, 24 Vac loads.  
Fig 8. Reset control with 120 Vac input, 120 Vac loads.  
63-2248—4  
6
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
ELECTRONIC SERIES 90  
MODUTROL MOTOR  
C/F  
T1 T2  
B
R
W
SET  
ENTER  
SELECT  
SA SB  
SENSOR A  
24 VAC  
SENSOR B  
2
3
5
1
4
6
7
8
SA TOD 24V SB  
3
2
1
POWER  
INPUT  
B
R
W
1
LOAD 1  
OUTPUT 2  
NO COMNC  
T775J  
USE SEPARATE TRANSFORMER FOR T775 WHEN POWERING FROM 24 VOLTS.  
1
NOTE: T775J1019, T775J1043 PROVIDE ELECTRONIC SERIES 90 OUTPUT THAT  
WILL NOT DRIVE 135 OHM SLIDEWIRE DEVICES.  
PROPER OUTPUT LEVELS CAN BE CHECKED BY MEASURING THE OPEN CIRCUIT VOLTAGE  
BETWEEN TERMINALS 1 (W) AND 2 (R):  
MINIMUM (DRIVE CLOSED): 0.17 VDC  
MAXIMUM (DRIVE OPEN): 1.7 VDC  
M8115A  
Fig. 11. Reset control with 24 Vac input, Series 90 and 24 Vac loads.  
4-20mA MODULATING  
MOTOR OR ACTUATOR  
C/F  
_
+
T1 T2  
SET  
ENTER  
SELECT  
SA SB  
SENSOR A  
SENSOR B  
1
2
3
5
4
6
7
8
SA TOD 24V SB  
3
2
1
POWER  
INPUT  
-
+
BLK  
120 VAC  
OUTPUT 2  
NO COMNC  
WHT  
LOAD 1  
M8116  
Fig. 12. Reset control with 120 Vac input, 4 to 20 mA and 120 Vac loads.  
7
63-2248—4  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
MODULATING MOTOR WITH  
VOLTAGE CONTROL INPUT  
C/F  
T1 T2  
C
F
R
SET  
ENTER  
SELECT  
SA SB  
SENSOR A  
SENSOR B  
2
3
5
1
4
6
7
8
SA TOD 24V SB  
3
2
1
POWER  
INPUT  
-
+
BLK  
240 VAC  
OUTPUT 2  
NO COMNC  
RED  
LOAD 1  
M8117  
Fig. 13. Reset control with 240 Vac input, 240 Vac and 0 to 18 Vdc loads.  
1
L2  
L1  
(HOT)  
M954 OR M955  
MODUTROL® MOTOR  
DIP SWITCHES  
FOR SENSOR TO  
LOAD SELECTION.  
R
TR  
C/F  
W
TR  
2
B
SET  
ENTER  
SELECT  
SA SB  
M954 OR M955  
MODUTROL® MOTOR  
2
3
5
1
4
6
7
8
R
SA TOD 24V SB  
TR  
3
2
1
W
TR  
B
R W  
B
M954 OR M955  
MODUTROL® MOTOR  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NO COMNC  
R
TR  
W
TR  
B
NOTE:  
USE SEPARATE TRANSFORMER FOR T775 WHEN POWERING FROM 24 VAC.  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
USE 1300 OHM RESISTOR FOR 2 MOTORS, 910 OHMS RESISTOR FOR 3 MOTORS. 4047EAU RESISTOR KIT  
(SHIPPED WITH M954, M955 MOTORS) INCLUDES 1300 OHM AND 910 OHM RESISTORS.  
M4717  
Fig. 14. Reset control with Series 90 Modutrol® Motor.  
63-2248—4  
8
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
DIP SWITCHES  
FOR SENSOR TO  
LOAD SELECTION.  
ML984 ACTUATOR  
C/F  
T1 T2  
B
R
W
SET  
ENTER  
SELECT  
SA SB  
2
3
5
1
4
6
7
8
SA TOD 24V SB  
3
2
1
250 OHM  
B R W  
POWER  
INPUT  
1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NO COMNC  
M4716  
Fig. 15. Reset control with ML984 Valve Actuator.  
Use shielded cable if any of the above conditions cannot be  
avoided.  
CAUTION  
The T775J will not allow the user to program for both  
heating and cooling loads to be energized at the same  
time.  
Device Setup  
³ Determine the loads to be controlled and the operating  
mode (heat or cool) and enter on the worksheet.  
If this situation results, cooling loads will be energized  
and heating loads will be prevented from also  
energizing. The number (1,2) of these nonenergized  
loads will flash, along with the word HEAT, to indicate  
a call for both heating and cooling loads controlled by  
one sensor has occurred and to alert the user to  
reprogram the affected control values.  
For example: Load 1: Compressor 1 (cool)  
Setpt 1 _____  
Diff 1 _____  
On at _____  
Off at _____  
· Determine the setpoint (Setpt) and the switching  
differential (Diff) temperatures for each on/off load and  
enter on the worksheet.  
¿ To calculate the Reset Ratio to be used, determine the  
number of degrees the setpoint for the control sensor A  
should be reset (Reset Ratio A Value) to compensate  
for a change in the reset compensation sensor B (Reset  
Ratio B Value). Enter the values on the Device  
Programming Worksheet (values should be whole  
numbers from 1 to 30).  
For example: Load 1: Compressor 1 (cool)  
Setpt 1 78°F  
Diff 1 4°F  
On at 82°F  
Off at 78°F  
» Refer to the Control Algorithm section to calculate the  
load on and off temperatures and enter on the  
worksheet. Remember that on/off outputs are off at  
setpoint in both the heating and cooling operating  
modes. When in cooling mode, the load will be turned  
on at setpoint plus the differential. When in heating  
mode, the load will be turned on at setpoint minus the  
differential.  
CAUTION  
A reset ratio lower than one can result in unstable  
control. Widening the throttling range and/or  
differential will minimize this effect.  
9
63-2248—4  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
´ Determine the desired Reset Direction (up or down)  
and enter on the Device Programming Worksheet. This  
will determine if the setpoint for the control Sensor A  
will be reset up or down.  
² Determine the desired Reset Compensation Setpoint  
for Sensor B. Enter the value on the Device  
Programming Worksheet.  
´ To avoid this time delay, press Select.  
² Press Select and Enter keys simultaneously to begin  
programming the load operating mode (heat or cool).  
The display will indicate heat or cool and the stage  
number.  
Press Set (down arrow) to change to cooling. Set (up  
arrow) will change back to heating.  
Determine whether the desired Reset Action should  
occur above or below the Reset Compensation  
Setpoint. Enter above or below on the Device  
Programming Worksheet.  
º Press Enter to program the displayed mode into  
memory.  
¾ Press Select to go to the next step.  
µ Repeat steps 6 through 8 for additional changes.  
º Remove the T775J cover and enter the values listed on  
the worksheet and the date in the first column on the  
label inside the T775J cover.  
Programming Stage Control Values  
³ If you have a 0 to 18 Vdc output T775J, go to the  
Calibration Procedure for 0 to 18 Vdc Output T775  
before continuing to program the stage control values.  
The Series 90 and 4-20 mA output T775J Controller  
does not require calibration, so proceed to step 2.  
Device Programming Worksheet  
Load 1:  
Setpt 1 ___________  
On at __________  
Diff 1 or Throttling Range __ Off at __________  
IMPORTANT  
Load 2:  
When programming all stages ,it is important to note  
that the first stage designated on the LCD display is  
always the modulating output.  
Setpt 2 ___________  
Diff 2 ____________  
On at __________  
Off at __________  
Reset Ratio:  
Reset Ratio B Value ______  
Reset Ratio A Value ______  
· Press Select to display the current stage setpoint.  
» Press Set (up arrow) to increase or Set (down arrow) to  
decrease the display to the desired setpoint.  
¿ Press Enter to enter the displayed value into memory.  
´ Press Select to display the current stage throttling  
range or switching differential.  
² Press Set (up arrow) to increase or Set (down arrow) to  
decrease the display to the desired throttling range or  
switching differential.  
Reset Direction __________________________  
Compensation Setpoint Sensor B ____________  
ResetAction _____________________________  
Press Enter to enter the displayed value into memory.  
º Repeat steps 2 through 7 to program each additional  
stage.  
Device Programming  
Factory Default Values  
When power is initially applied to the T775J, the control points  
will be at the factory set default values. Default values are:  
IMPORTANT  
After initial programming, altering the setpoint up or  
down for stage 1 will result in a change in setpoint 2  
by the same number of degrees and in the same  
direction. If increasing or decreasing the setpoint for  
stage 1 results in exceeding the control limits (-40°F  
to +220°F) for stage 2, the control will not allow the  
user to enter a value for stage 1 higher or lower than  
this limit. This will allow for easy sequential output  
staging to be modified while keeping the margin  
intact between setpoints.  
Differential/  
Operating  
Mode  
Stage  
Stage 1  
Stage 2  
Setpoint  
72°F  
Throttling Range  
2°F  
2°F  
Heat  
Heat  
70°F  
³ Set the reset direction determined previously by setting  
the DIP switch in the upper right corner of the T775  
(see Fig. 5). Switch 1 should be open to reset the  
control point up and closed to reset the control point  
down.  
· Set the reset action determined previously by setting  
the DIP switch in the upper right corner of the T775J.  
Switch 2 should be open if the reset is to occur when  
the outdoor temperature is below the reset  
Programming Reset Values  
³ Press Select to display the current reset compensation  
setpoint (Sensor B).  
· Press Set (up arrow) to increase or Set (down arrow) to  
decrease the display to the desired setpoint.  
» Press Enter to enter the displayed value into memory.  
compensation setpoint and closed if the reset is to  
occur when the outdoor air temperature is above the  
reset compensation setpoint.  
¿
Press Select to display the current Reset Ratio B  
value.  
´ Press Set (up arrow) to increase or Set (down arrow) to  
decrease the display to the desired Reset Ratio B  
value.  
² Press Enter to enter the displayed value into memory.  
Press Select to display the current Reset Ratio A.  
º Press Set (up arrow) to increase or Set (down arrow) to  
decrease the display to the desired Reset Ratio A  
value.  
» Before programming the T775J, verify that the °F/°C  
selection jumper is properly installed. The T775J is  
shipped from the factory with the jumper installed in the  
°F position. If °C is desired, remove the jumper.  
¿ Apply power to the device. The device will begin  
counting down from 210. This countdown sequence will  
last for approximate 3-1/2 minutes.  
63-2248—4  
10  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
¾ Press Enter to enter the displayed value into memory.  
Calibration Setpoint for Cooling Mode (Fig. 13)  
Setpoint for calibrating the lower voltage level (closed  
position):  
µ Press Select four times to return to stage 1 parameters.  
Scroll through the programming loop a second time to  
confirm that the appropriate values have been entered  
into memory.  
A
B
Sensed Temperature  
Add 3° F or C to above:  
Calibration Setpoint:  
78°  
+3°  
81°  
NOTE: The T775J has three options for displaying the  
sensed temperatures:  
1. Sensor A only.  
2. Sensor B only.  
3. Alternating between Sensor A and Sensor B.  
Calibration Setpoint for Heating Mode:  
A
B
Sensed Temperature:  
Subtract 3° F or C from above:  
Calibration Setpoint  
78°  
-3°  
75°  
¸ Press Select after viewing the switching differential for  
the final stage to display Sensor A temperature only.  
¹ Press Select again to display Sensor B temperature  
only.  
Ƹ Press Select again to alternate the display between  
Sensor A temperature and Sensor B temperature at  
approximately five second intervals.  
ƹ Before replacing the cover on the T775J, check to see  
that the control values have been recorded on the label  
on the back of the cover.  
Calibrate the Lower Voltage Level (Closed Position).  
³ Read displayed temperature of sensor that is controlling  
stage 1.  
· Press Select until the setpoint for stage 1 is displayed.  
» If stage 1 is in the HEAT mode, press Set (down arrow)  
until the setpoint is at least three degrees below the  
temperature in step 1.  
¿ If stage 1 is in the COOL mode, press Set (up arrow)  
until the setpoint is at least three degrees above the  
temperature in step 1.  
NOTE: The control values programmed into memory will not  
be lost because of a power failure.  
´ Press Enter to enter this value into memory.  
² Press Select once so that the throttling range is  
displayed.  
Calibration Procedure for 0 to 18 Vdc Output T775J  
Press Set (up arrow) or Set (down arrow) until the  
throttling range is two degrees.  
º Press Enter to enter this value into memory.  
¾ Connect voltmeter as shown in Fig. 8.  
µ Press Select until Sensor A is displayed (if the sensed  
temperature has drifted from step 1, you may need to  
repeat steps 2 through 8).  
¸ Turn the zeroing voltage potentiometer with a  
screwdriver until the desired lower voltage (i.e., 2V, 6V,  
etc) is displayed on the voltmeter.  
NOTE: The 0-18 Vdc Output T775J models have field  
selectable starting voltages and spans and will  
require calibration. The Series 90 and 4-20 mA  
output devices require no calibration.  
³ Disconnect power to the device.  
· Remove the device cover and disconnect the load from  
the plus and minus outputs. Connect a dc voltmeter to  
the plus and minus modulating outputs of the T775J  
(see Fig. 12).  
» Loosen the screw in the upper right corner of the T775J  
approximately six turns with a screwdriver (see  
Fig. 12).  
¿ Rotate the display printed wiring board outward from  
the device until it is approximately perpendicular to the  
enclosure (see Fig. 12).  
´ The T775 is factory set to a span of 8 Vdc. To select a  
different span (3 Vdc, 14 Vdc, or 17 Vdc), change the  
switch positions on the voltage selection switch by  
opening the switch for 8 Vdc and closing the switch for  
the chosen span (see Fig. 12).  
² Apply power to the device.  
Press Select until Sensor A temperature is displayed.  
º Record the sensed temperature.  
¾ Determine the operating mode for stage 1 (Heat or  
Cool). Choose the appropriate example to follow.  
Calculate the setpoints to be used for calibrating the  
device in column B, following the example in column A.  
¹ Confirm upper voltage level:  
Record the sensed temperature for sensor  
controlling stage 1.  
Press Select until stage 1 setpoint is displayed.  
If stage 1 is in the HEAT mode, press Set (up  
arrow) until setpoint is at least three degrees  
above the sensed temperature.  
If stage 1 is in the COOL mode, press Set (down  
arrow) until setpoint is at least three degrees  
below the sensed temperature.  
Press Enter to enter this value into memory.  
Record the (desired) upper voltage level.  
If the value is not correct, make sure the correct  
span switch is depressed and the stage is in the  
correct mode of operation (HEAT or COOL).  
Verify which sensor is controlling stage 1.  
Ƹ Rotate the display printed wiring board back into the  
device and tighten the screw in the upper right corner.  
ƹ Disconnect the voltmeter from the modulating outputs  
and connect the load to the plus and minus terminals of  
the modulating terminal block.  
ƺ Return to Programming Stage Control Values to enter  
the desired stage control values.  
11  
 
63-2248—4  
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
STEP 1  
STEP 2  
VOLTAGE SPAN  
SELECTION SWITCH  
ZEROING  
VOLTAGE DIAL  
1
2
3
4
OPEN  
17  
8 14  
3
SET  
ENTER  
SELECT  
SA SB  
2
3
5
1
4
6
7
8
SA  
24V SB  
TOD  
3
2
1
3
2
1
MODULATING  
VOLTAGE  
OUTPUT  
SENSOR INPUT,  
TOD, AND  
24 VAC  
TERMINALS  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NOCOM NC  
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NOCOM NC  
GENTLY PULL THE TOP PWB UPWARDS AROUND  
ITS HINGE. STOP WHEN THE PWB IS  
PERPENDICULAR TO THE ENCLOSURE.  
REMOVE FRONT COVER AND LOOSEN SCREW  
IN UPPER RIGHT CORNER OF DEVICE WITH A  
SCREWDRIVER.  
1
2
3
4
CLOSED  
OPEN  
STEP 3  
N
P
8
O
3
E
14 17  
VOLTAGE SPANS  
1
2
3
4
WHEN SWITCH IS DEPRESSED, THE  
VOLTAGE RANGE IDENTIFIED BY  
THE VOLTAGE SPAN BELOW THAT  
SWITCH IS SELECTED. IN THIS  
CASE, A VOLTAGE SPAN ON 8 VDC  
HAS BEEN SELECTED. THIS SPAN  
CAN BE 2-10 VDC, 10-18 VDC, ETC.,  
BY USE OF ZEROING DIAL.  
OPEN  
17  
8 14  
3
VOLTMETER  
1
3
2
18  
0
+
-
OUTPUT 1  
NO COM NC  
OUTPUT 2  
NOCOM NC  
CONNECT THE MODULATING VOLTAGE OUTPUT  
TO A VOLTMETER. USING A SCREWDRIVER,  
ADJUST THE LOWER LIMIT OF THE VOLTAGE TO THE  
DESIRED LEVEL ACCORDING TO THE STEPS  
OUTLINED IN CLAIBRATION PROCEDURE FOR  
0 TO18 VDC OUTPUT.  
M1345B  
Fig. 16. Voltage span selection.  
63-2248—4  
12  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
HEATING MODE  
MODULATION  
SENSED  
TEMPERATURE = 78oF  
THROTTLING  
RANGE  
DEAD BAND  
CALIBRATION  
SETPOINT 75oF  
MODULATION  
* DEADBAND IS 1/8 OF THE THROTTLING RANGE  
COOLING MODE  
CALIBRATION  
SETPOINT 81oF  
MODULATION  
SENSED  
TEMPERATURE = 78oF  
THROTTLING  
RANGE  
DEAD BAND  
MODULATION  
M2149C  
* DEADBAND IS 1/8 OF THE THROTTLING RANGE  
Fig. 17. Explanation of calibration setpoints for heating and cooling modes.  
the modulating output will be designated as stage 1 on the  
DESCRIPTION/OPERATION  
LCD display. Although the modulating output is designated as  
stage 1, it can be programmed to energize after the second  
stage is energized.  
Control Algorithm  
Reset Control  
The T775J offers four different reset configurations and an  
adjustable reset ratio between 30 to 1 and 1 to 30.  
The T775J operates as a reset controller with two sensor  
inputs. The outdoor sensor is designated Sensor B and the  
control medium sensor is Sensor A. Sensor B is wired to pins  
7 and 8 of the input terminal block, while Sensor A is wired to  
pins 1 and 2. The T775J is capable of providing modulating or  
relay outputs for reset control. Each stage of the T775J has its  
own independent setpoint that can be configured to operate in  
the cooling or heating mode. The mode of operation for each  
stage is user determined by the programming keys.  
The reset ratio expresses the amount of change in the  
heating or cooling medium control point caused by a change  
in the outdoor temperature. It is the ratio of outdoor  
temperature change to heating or cooling control point  
change (Sensor B/Sensor A). The reset ratio can be an  
inverse ratio (when the outdoor temperature goes down, the  
control point goes up) or a direct ratio (when the outdoor  
For reset control with two outputs, one of which is modulating,  
13  
 
63-2248—4  
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
RESET DIRECTION SWITCH  
temperature goes down, the control point goes down). The  
type of ratio is selected by using the two DIP switches  
provided.  
RESET DIRECTION SWITCH: WILL RESET  
THE COUNTROL POINT UP (WHEN  
OPEN) OR DOWN (WHEN CLOSED).  
1
2
RESET ACTION SWITCH  
The four possible reset operating configurations are illustrated  
and explained in Fig. 18. Switches 1 and 2 are shown but  
switches 3 and 4 are unused; however, the location of these  
DIP switches is shown in Fig. 5.  
RESET ACTION SWITCH: RESET IF THE  
OUTDOOR TEMPERATURE (SENSOR B) IS  
ABOVE (WHEN CLOSED) OR BELOW  
(WHEN OPEN) THE OUTDOOR  
OPEN  
CLOSED  
TEMPERATURE SETPOINT.  
SWITCH  
SWITCH  
CAUTION  
A reset ratio lower than one can result in unstable  
control. Widening the throttling range and/or  
differential minimizes this effect.  
OPEN  
CLOSED  
PWB  
PWB  
SIDEVIEW  
RESET DIRECTION SWITCH OPEN  
Proportional + Integral Modulating Control  
1
2
IF THE OUTSIDE SENSOR (B)  
Proportional + Integral (P+I) control provides fast, responsive  
operation of the controlled devices in reacting to temperature  
changes by providing an output signal proportional to the  
deviation between setpoint and actual temperature. An  
integral proportion also provides a time dependent output  
signal that is dependent on the length of time of the deviation  
between actual set point and sensed temperature.  
TEMPERATURE IS BELOW THE OUTSIDE  
TEMPERATURE SETPOINT,THE CONTROL  
POINT WILL BE INCREASED BY THE  
RESET RATIO.  
RESET ACTION SWITCH OPEN  
OPEN  
CLOSED  
RESET DIRECTION SWITCH CLOSED  
IF THE OUTSIDE SENSOR (B)  
TEMPERATURE IS BELOW THE OUTSIDE  
TEMPERATURE SETPOINT,THE CONTROL  
POINT WILL BE DECREASED BY THE  
RESET RATIO.  
1
The P + I algorithm places the control setpoint in the middle  
of the throttling range. A deadband around setpoint exists and  
is proportional to the throttling range. For the T775, this  
deadband is 1/8 of the throttling range.  
2
RESET ACTION SWITCH OPEN  
OPEN  
CLOSED  
There are three modulation options available for the T775J  
(see Fig. 20 for modulating output connecting terminals).  
RESET DIRECTION SWITCH OPEN  
IF THE OUTSIDE SENSOR (B)  
1
Fig. 18. Reset switch configuration.  
TEMPERATURE IS ABOVE THE OUTSIDE  
TEMPERATURE SETPOINT,THE CONTROL  
POINT WILL BE INCREASED BY THE  
RESET RATIO.  
2
RESET ACTION SWITCH CLOSED  
OPEN  
CLOSED  
RESET DIRECTION SWITCH CLOSED  
IF THE OUTSIDE SENSOR (B)  
1
TEMPERATURE IS ABOVE THE OUTSIDE  
TEMPERATURE SETPOINT,THE CONTROL  
POINT WILL BE DECREASED BY THE  
RESET RATIO.  
2
RESET ACTION SWITCH CLOSED  
OPEN  
CLOSED  
M8110A  
Fig. 19. Summary of action/direction switches.  
63-2248—4  
14  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
SETPOINT "B" (OUTSIDE TEMPERATURE)  
BELOW  
ABOVE  
RESET DIRECTION  
SWITCH  
RESET DIRECTION  
SWITCH  
A
A
C
B
D
B
D
RESET ACTION  
SWITCH  
RESET ACTION  
SWITCH  
C
RESETS CONTROL SETPOINT A UP  
WHEN SENSOR B (OUTSIDE  
RESETS CONTROL SETPOINT A UP  
WHEN SENSOR B (OUTSIDE  
TEMPERATURE) IS BELOW SETPOINT.  
TEMPERATURE) IS ABOVE SETPOINT.  
RESETS CONTROL SETPOINT A DOWN  
WHEN SENSOR B (OUTSIDE  
RESETS CONTROL SETPOINT A DOWN  
WHEN SENSOR B (OUTSIDE  
TEMPERATURE) IS BELOW SETPOINT.  
TEMPERATURE) IS ABOVE SETPOINT.  
RESET DIRECTION  
SWITCH  
RSWESITECTHDIRECTIONA  
A
C
B
B
D
RESET ACTION  
RESET ACTION  
SWITCH  
C
D
SWITCH  
A. SWITCH 1 CONTROLS THE RESET DIRECTION.  
LEFT RESETS SENSOR A CONTROL POINT (BOILER OR CHILLER WATER TEMPERATURE UP;  
RIGHT RESETS IT DOWN.  
B. SWITCH 2 CONTROLS THE RESET ACTION.  
LEFT RESETS AS SENSOR B (OUTDOOR TEMPERATURE) DROPS BELOW SETPOINT B;  
RIGHT RESETS AS IT RISES ABOVE IT.  
M4719  
C. SWITCHES 3 AND 4 ARE NOT USED.  
4-20 mA: This is a general purpose current mode output that can drive a 600 ohm maximum load without output current  
15  
 
63-2248—4  
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
degradation. This modulation output can be used with  
Honeywell Inc Modutrol IVTM Motors that accept an input  
signal of 4-20 mA or other Honeywell Inc motors with the  
use of resistor kits.  
A second set of DIP switches provides voltage range  
selection for 0 to 18 Vdc modulating devices. The span  
corresponding to each switch is given on the printed wiring  
board below each switch. Fig. 16 shows the location of this  
switch, the zeroing dial, and how to set the voltage span. See  
Fig. 19 for a summary of action/direction switches.  
0-18 Vdc (voltage ranging): This output mode is intended  
as a general purpose voltage output capable of driving a  
2 kohm load minimum. The span of voltage output is user  
selectable via a DIP switch (see Fig. 14). The spans  
offered are 3, 8, 14 and 17 volts. A zero adjustment dial is  
provided to allow the user to select common ranges such  
as 4-7 Vdc, 6-9 Vdc, 2-10 Vdc, 10.5 -13.5 Vdc, 14.5-17.5  
Vdc, 1-15 Vdc, and 1-18 Vdc. This modulation output can  
be used with Modutrol IV™ Motors that accept a voltage  
span comparable to any of the above. The device is factory  
set at the 2 to 10 Vdc span.  
Keypad Programming and Display  
The T775J uses a liquid crystal display (LCD) for interactive  
prompting during programming and display of sensed  
temperatures and assigned setpoint and differential values.  
User programming of the T775J is through four programming  
keys.  
3
2
1
Heat Operation Mode  
Throttling range is centered around the setpoint.  
Modulating outputs are at the minimum or closed position  
at setpoint plus one-half of the throttling range.  
Modulating outputs are at the maximum or open position  
at setpoint minus one-half of the throttling range.  
Relay outputs are energized at setpoint minus differential  
and de-energized at setpoint.  
B
R
-
W
+
(SERIES 90)  
(4-20 mA AND 0-18 Vdc)  
M2133A  
Fig. 20. Modulating output terminals.  
Cooling Operation Mode  
Programming Keys  
The throttling range is centered around the setpoint.  
Modulating outputs are at the minimum or closed position  
at setpoint minus one-half of the throttling range.  
Modulating outputs are at the maximum or open position  
at setpoint plus one-half of the throttling range.  
Relay outputs are energized at setpoint plus differential  
and de-energized at setpoint.  
The four programming keys are Select, Up arrow, Down  
arrow and Enter.  
Select key sequentially prompts the user for what  
parameter is being displayed: setpoint, differential, stage  
energized, heat or cool (operation mode), 1, 2 (indicating  
assigned stage). Once the last parameter value is viewed,  
pressing the Select key will again display the control  
values from the beginning of the display loop.  
Contact Closure Override Input  
Up and Down arrow keys allow the displayed parameters  
to be increased or decreased. After pressing the Select  
key, a control value can be changed by using the arrow  
keys. Control values will be increased or decreased by  
1° F or C each time the arrows are depressed.  
Enter key places the new value into the memory of the  
microprocessor. A control value or operation will not be  
effective in the memory until the Enter key is depressed.  
Control values and operation selection will remain in the  
device memory even after power is removed.  
A two terminal input is provided to allow the user to override a  
relay energized condition of all outputs. When used with  
modulating devices, a contact closure override input causes  
the output to return to its minimum position. This function is  
generated by a contact closure between terminal pins 3 and 4  
of the terminal block for sensor input shown in Fig. 4. This can  
be achieved manually or by using an EMS controller or time  
clock with normally open contacts; i.e., W7505, S7005.  
When contact closure override is active, the display will show  
the number of stages that would have been energized and  
“STAGE ENERGIZED’’ will flash.  
The Select and Enter keys must be pressed  
simultaneously to change the control algorithm from  
heating to cooling or from cooling to heating. These  
parameters (heat and cool) are not displayed during  
normal Select key sequences. The only parameters  
displayed after pressing the Select and Enter keys at the  
same time are stage indication and Heat or Cool. To  
change the operation from heating to cooling or vise versa  
for a desired output stage, use the arrow keys as required.  
Once the mode is changed, depressing the Enter key is  
necessary to enter this change into the microprocessor  
memory. The next stage of heat or cool assignment will  
appear after the Select key is pressed. When all stages are  
selected, the display will revert back to sensed  
°
F/°C Selection  
A single jumper plug controls °F/°C indication of the displayed  
temperature value. The location of this jumper is shown in Fig.  
5. The unit is shipped with the jumper installed in the °F  
mode. Remove the jumper plug for the °C mode. Remove and  
reapply power if the jumper is removed with the device  
powered.  
DIP Switch Selections  
DIP switches, see Fig. 18, are provided for assignment of the  
reset configurations.  
temperature and load energized status.  
63-2248—4  
16  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
The device hardware was configured to a nonexistent  
device. This error cannot be field repaired. Replace  
the device.  
Display  
Once power is applied or restored to the device, the display  
will count down from 210 until the display reads zero, during  
which time any previously energized outputs will be de-  
energized. This is intended to protect compressors in the  
event of a power outage.  
OE—ROM Error.  
The internal ROM of the microprocessor is defective.  
This error cannot be field repaired. Replace the  
device.  
AE—RAM Error  
To avoid viewing this entire countdown, press the Select key.  
The LCD display will now show what it normally reads: load  
(sensed) temperature, stages energized, and which Sensor  
(A or B) is being read. At any time during the programming or  
review procedure, the display will revert back to showing the  
sensed temperature and stage status indication 60 seconds  
after the last key closure.  
The internal RAM of the microprocessor is defective.  
This error cannot be field repaired. Replace the  
device.  
Setpoint Calibration  
To maintain temperature accuracy, sensor wires should be 18  
AWG two-conductor (18/2). If the length of the sensor wire  
exceeds 400 feet, recalibration will be necessary to maintain  
accuracy (see Fig. 21). Table 2 shows the corresponding  
temperature offset that should be used for different sensor  
wire lengths. This temperature offset should be added to the  
desired temperature setpoint for these applications.  
The user has three display options to select. The display can  
be configured to alternately indicate Sensor A and Sensor B  
sensed temperature at a five second rate or the display can  
be locked on to sensor A or sensor B to sense temperature  
continuously.  
This selection is accomplished by stopping at Sensor A or  
Sensor B sensed temperature points in the Select key  
scrolling loop. To lock on to either sensor, the user must scroll  
the Select key through the loop to select the sensed  
temperature prompt desired. The display will stick to that  
parameter until the Select key is activated to advance the  
loop. When the loop is stopped at any other prompt, the  
display will alternately indicate Sensor A and Sensor B  
sensed temperatures after 60 seconds from the last key  
closure or immediately after the Select key is pressed at the  
end of the programming sequence.  
RESISTANCE  
(OHMS)  
4200  
4000  
3800  
3600  
3484 6.5 OHMS  
AT 77°F (25°C)  
3400  
Error Messages  
There are seven error messages that can be displayed in  
response to software or hardware problems with the T775J.  
The error codes that may be seen flashing on the display are:  
SF—Sensor Failure.  
3200  
F
100 120 140 160 180 200 220  
20  
-7  
40  
60  
80  
The display flashing SF indicates an out-of-range  
sensor. Make sure the sensors are properly  
connected. For the T775J, stage 2 load will be de-  
energized when this error message is flashing for  
Sensor B. When this message is flashing for Sensor  
A only, stage 1 will not be de-energized.  
C
100  
M2829  
0
10  
20  
30  
40  
50  
60 70  
80  
90  
TEMPERATURE (DEGREES)  
Fig. 21. Resistance versus temperature  
performance characteristics.  
EF—EEPROM Failure.  
The values read back from the EEPROM are not the  
same as written into the EEPROM. The EEPROM is  
not intended for field repair. Replace the device.  
CF—Calibration Failure.  
Table 2. Sensor Wire Length/Calibration Offset  
(Using 18 Awg Wire).  
A calibration resistor reading was not within the range  
of the Analog to Digital converter. This error message  
can not be field repaired. Replace the device.  
OF—Stray interrupt Failure.  
An unused interrupt occurred. This error cannot be  
field repaired. Replace the device.  
CE—Configuration Error.  
Sensor Wire Length (ft)  
0-399  
Calibration Offset (°)  
None required.  
400-599  
1
2
3
600-799  
800-1000  
17  
 
63-2248—4  
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
g. Divide Reset Ratio B value by Reset Ratio A  
CHECKOUT  
value.  
h. Multiply the result in step g. by Temp Diff  
(step a.).  
After the controller is installed and wired, apply power. Using  
the programmed control values, verify device operation after  
completing Table 3.  
³ As illustrated in the example, record the sensed  
temperatures for both Sensor A and Sensor B as  
displayed on the controller. Sensor A senses the  
temperature for loads 1 and 2. Sensor B senses the  
temperature that determines the amount of reset.  
· Write the operating mode for each stage in the  
Checkout Table (heat or cool).  
» Write Sensor A temperature for each load on the  
Sensed Temp line.  
¿ Write Sensor B temperature in the space indicated in  
the Checkout Table.  
´ Press Select until Setpoint B is displayed.  
² Write Setpoint B in the space indicated in the Checkout  
Table.  
Determine the reset direction (up or down) from the  
Device Programming Worksheet in the Installation  
section and enter in the space indicated in the  
Checkout Table.  
º Determine the reset action (above or below) from the  
Device Programming Worksheet and enter in the space  
indicated in the Checkout Table.  
¾ Plot the programmed on and off (open/closed) values at  
which the device will energize and deenergize each  
output load by referring to the Device Programming  
Worksheet.  
i.  
If Reset Direction Switch is set to increase,  
disregard any negative signs and add the amount  
of reset calculated in step h. to the on/off values.  
If the Reset Direction Switch is set to decrease,  
disregard any negative signs and subtract the  
amount of reset calculated in step h. from the on/  
off values.  
j.  
k. Plot the new values on the appropriate Reset  
Load in the Checkout Table.  
¸ Verify which loads are energized by using the Checkout  
Table. As shown in the example, the display will indicate  
which stages are energized in the lower right-hand  
corner. (NOTE: If no stages are energized, the words  
stage energized will not appear.)  
NOTE: If the sensed temperature is between the on and  
off temperatures, the load may be either  
energized or deenergized. Refer to the Control  
Algorithm subsection of Description/Operation  
section for further explanation.  
¹ If an error message flashes, refer to the description of  
these messages in Error Messages subsection. If SF  
flashes, check the sensor connections. If they are  
properly connected and SF continues to flash, check  
the sensor location to assure it is located in an ambient  
condition that is within the sensor’s ambient capability  
(-40°F to +220°F).  
µ Calculate the amount of reset that exists using  
Formula 1.  
Ƹ If an error message other than SF flashes, the device  
cannot be field repaired. Replace the device.  
a. Subtract setpoint B from Sensor B and enter the  
result as Temp Diff.  
b. If the result is negative, reset will occur only if the  
Reset Action Switch is set for reset below  
setpoint. If the result is positive, reset will occur if  
the Reset Action switch is set for reset above  
setpoint.  
c. Determine if a reset condition exists.  
d. If no reset condition exists, On/Off Control Values  
have not been changed.  
For the Electronic Series 90 output (T775J1019 and  
T775J1043), proper output levels can be checked by  
measuring the open-circuit voltage between terminals 1(W)  
and 2(R):  
Minimum (Drive Closed) signal 0.17 Vdc.  
Maximum (Drive Open) signal 1.7 Vdc.  
e. Go to step 11.  
f. If a reset condition exists, calculate the amount of  
reset using Formula 2.  
63-2248—4  
18  
 
T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER  
Table 3. Checkout Table.  
Checkout Table Example  
Checkout Table  
Reset  
Value  
Load 1  
Reset  
Value  
Load 2  
Reset  
Value  
Load 1  
Reset  
Value  
Load 2  
Heat or  
Cool  
Heat or  
Cool  
Load 1  
Heat  
Load 2  
Heat  
Load 1  
Load 2  
Sensor  
Sensor A  
80°  
Sensor B  
10°  
A ____  
Sensor  
B ____  
120° Off  
116° On  
80°  
118° Off  
80°  
Sensed  
Temp  
80° Off  
76° On  
80°  
Sensed  
Temp  
78° Off  
74° On  
Setpoint B ____________  
Sensor B _____________  
Reset Ratio A _________  
Reset Direction __________  
Reset Action ____________  
Reset Ratio B ___________  
Setpoint B  
Sensor B  
Reset Ratio A  
30°  
10°  
1
Reset Direction Increase  
Reset Action  
Reset Ratio B  
Below  
2
FORMULA 1:  
FORMULA 1 EXAMPLE:  
Sensor B  
Sensor B = 10°F  
Setpoint B = 30°F  
-Setpoint B  
Temp Diff = _______________________  
FORMULA 2:  
Temp Diff =  
-20°F  
FORMULA 2 EXAMPLE:  
Amount of Reset = Reset Ratio B  
Reset Ratio A  
Amount of Reset = 2 x (-20) = -40  
1
19  
63-2248—4  
 
Home and Building Control  
Honeywell Inc.  
Home and Building Control  
Honeywell Limited-Honeywell Limitée  
740 Ellesmere Road  
Helping You Control Your World  
1985 Douglas Drive North  
Golden Valley, MN 55422  
Scarborough, Ontario  
QUALITY IS KEY  
M1P 2V9  
63-2248—4 Rev. 9-95 Printed in U.S.A.  
 

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