®
Chromalox
SERVICE REFERENCE
Installation Instructions
DIVISION
SALES
4
SECTION NWHO
(Supersedes PE408-3)
and
REFERENCE
PE408-4
RENEWAL PARTS IDENTIFICATION
161-048341-001
DATE
JULY, 1990
1-3/8” Conduit
Openings
16-1/16
Type NWHO-6
2” Pipe
Outlet
C
Circulation Heaters (for
Thermostat
Type AR
Regular and Fuel Oil Heating)
Specifications — Table A
Regular Oil Heaters
A
B
25”
Dimensions (In.)
Model
Volts
Phase
kW
W/In2
Mounting Lugs
A
B
C
3/8” - 16
Threaded Holes -
1-1/2” Deep
NWHO-61215
NWHO-61515
NWHO-62015
NWHO-62515
NWHO-63015
240 or 480
240 or 480
240 or 480
240 or 480
240 or 480
3 Δ
3 Δ
3 Δ
3 Δ
3 Δ
12
15
20
25
30
23
23
23
23
23
41-3/4
48-3/4
60-1/4
73-5/8
86-5/8
30
37
48-1/2
61-7/8
74-7/8
11-3/8
14-1/8
20-5/8
27-5/16
33-7/8
1-1/4” Centers
Fuel Oil Heaters
2” Pipe Inlet
NWHO-60825
NWHO-61025
NWHO-61225
NWHO-61525
NWHO-61825
240 or 480
240 or 480
240 or 480
240 or 480
240 or 480
1 or 3 Δ
8
15
15
15
15
15
41-3/4
48-3/4
60-1/4
73-5/8
86-5/8
30
37
48-1/2
61-7/8
74-7/8
11-3/8
14-1/8
20-5/8
27-5/16
33-7/8
3 Δ
3 Δ
3 Δ
3 Δ
10
12
15
18
8-5/8
GENERAL
The NWHO-6 series is a general-purpose regular and fuel oil
solution circulation heater intended for use indoors. It is designed
for 150 psig at 550˚F per ANSI standards.
212˚F limit stop.) Such thermostats function to control outlet tem-
peratures and to limit internal temperatures under abnormal flow
conditions. These controls do not fail safe.
The 6 steel-sheathed tubular elements are centered in a 5”
diameter galvanized steel heating chamber and welded to a
removable galvanized steel flange. The assembly is surrounded
by 1-1/2” insulation and sheet metal jacket.
Depending upon the order specifications, the NWHO-6 may
or may not be factory equipped with an AR or other Chromalox
thermostat. (Note: UL listed models are factory pre-set with a
WARNING: Users should install adequate back-up con-
trols and safety devices with their electric heating equip-
ment. Where the consequences of failure may be severe,
back-up controls are essential. Although the safety of the
installation is the responsibility of the user, Chromalox
will be glad to make equipment recommendations.
INSTALLATION
Note: A drain pipe located at the bottom of the heater should be pro-
vided and enough room left, when mounting heater, to allow draining
the heater.
Caution: Hazard of Electric Shock. Disconnect all
power before installing heater.
1. Vertical Mounting (Preferred) —
When the heater is vertically mounted, the terminal housing will
be at the top of the heater. The inlet pipe will be located on the side
near the bottom of the heater and the outlet pipe at the top.
The axis of the chamber will be in a vertical position as in the
photo above and as in Figure A.
2. Horizontal Mounting (Optional) —
When mounting heater horizontally, inlet and outlet pipes must
be up. In any other position, heater cannot be purged of air, and
elements may be seriously damaged. (See Figure B.)
Correct
Incorrect
Correct
Incorrect
Figure B — Horizontal Mounting
Figure A — Vertical Mounting
© 2010 Chromalox, Inc.
OPERATION
1. Do not heat solutions that are corrosive to the heating element
any electric circulation heater against failure by
sheath corrosion if such failure is the result of
operating conditions beyond our control.
2. Terminal ends of heater must be protected from drippings,
condensation, spray or direct spill-over of material. Their
presence at the terminals may damage heater electrical insula-
tion. Liquid-tight terminal enclosures are available to protect
heater. Contact your Local Chromalox Sales office.
sheath or the heating chamber.
WARNING: Type NWHO Circulation Heaters are
equipped with steel heating elements and galva-
nized-steel heating chambers. It is the responsibil-
ity of the user to know the chemical composition
of the corrosive solution and the character of the
materials entering the solution as well as the cor-
rosive effect of the solution upon the heating ele-
ments and chamber. Chromalox cannot warrant
3. If foreign material is carried by the liquid flow, install suitable
filters in the inlet pipe line to the heater.
4. Do not allow heater to operate when liquid flow is interrupted.
MAINTENANCE
3. Periodically check temperature control and limit control oper-
ation to insure accurate and safe process operations.
4. Check all electrical connections periodically and retighten
connections which may have loosened in service. Replace wire
and wire terminals which show signs of oxidation which would
interfere with establishment of reliable electrical connections.
1. WARNING: Hazard of Electric Shock. Disconnect all
power before servicing heater.
2. Remove heating element assembly periodically to check
heater sheath for scaling, corrosion or excessive oxidation.
Correct operating conditions to minimize sheath deterioration.
RENEWAL PARTS IDENTIFICATION
Fuel Oil Heaters
Regular Oil Heaters
Model
Volts
Phase
kW
Heating Element
Model
Volts
Phase
kW
Heating Element
NWHO-60825
NWHO-60825
NWHO-60825
NWHO-60825
240
240
480
480
1
3 Δ
1
8
8
8
8
155-115844-004
155-115844-005
155-115844-006
155-115844-007
NWHO-61215
NWHO-61215
240
480
3 L
3 L
12
12
155-115846-028
155-115846-030
3 Δ
NWHO-61515
NWHO-61515
240
480
3 L
3 L
15
15
155-115846-035
155-115846-037
NWHO-61025
NWHO-61025
NWHO-61025
NWHO-61025
240
480
240
480
3 Δ
3 Δ
3 Δ
3 Δ
10
10
12
12
155-115844-012
155-115844-014
155-115844-019
155-115844-021
NWHO-62015
NWHO-62015
240
480
2-3 L
3 L
20
20
155-115846-042
155-115846-044
NWHO-62515
NWHO-62515
240
480
2-3 L
3 L
25
25
155-115846-047
155-115846-049
NWHO-61525
NWHO-61525
NWHO-61525
NWHO-61525
240
480
240
480
3 Δ
3 Δ
3 Δ
3 Δ
15
15
18
18
155-115844-023
155-115844-025
155-115844-027
155-115844-029
NWHO-63015
NWHO-63015
240
480
2-3 L
3 L
30
30
155-115846-051
155-115846-053
Note: When ordering parts for Model Numbers suffixed by “XX” or any other letter or letters not specifically identified on this instruction sheet, order Renewal Parts on special order basis, giving name of part,
part number, model number and description.
PARTS COMMON TO ALL HEATERS
Gasket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132-017222-016
Thermostat (AR2525) . . . . . . . . . . . . . . . . . . .300-013863-038
Thermostat (AR5525) . . . . . . . . . . . . . . . . . . .300-013863-039
Limited Warranty:
Please refer to the Chromalox limited warranty applicable to this product at
2150 N. RULON WHITE BLVD., OGDEN, UT 84404
Phone: 1-800-368-2493
99 - 063
TA - R9 - EF
Litho in U.S.A.
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