Installation, Operation
and
4
NWH
(Supersedes PE424)
PE424-1
161-058005-001
RENEWAL PARTS IDENTIFICATION
APRIL, 1999
151/8”
Type NWH-18 Circulation
Heater for Water Heating
2 1/2” Pipe
Outlet
(150 Pound Construction)
Specifications — Table A
Dimensions (In.)
A
Model
Volts
Phase kW W/In2
A
B
C
3/4-10 Tap
Mounting
Lugs
B
457/
8
2411/
3211/
3911/
475/
5613/
6513/
7513/
16
16
16
16
16
16
16
213/
293/
363/
4313/
535/
625/
725/
16
16
16
16
16
16
16
C
NWH-185015
NWH-187515
240 or 480
240 or 480
3
3
3
3
3
3
3
50
75
42
45
537/
8
NWH-1810015 240 or 480
NWH-1812515 240 or 480
NWH-1815015 240 or 480
NWH-1817515 240 or 480
NWH-1820015 240 or 480
100 49
125 50
150 50
175 50
200 50
607/
8
681/
78
2
87
97
2 1/2” Pipe
Inlet
GENERAL
WARNING: This heater is not intended for use in
hazardous atmospheres where flammable vapors,
gases, liquids or other combustible atmospheres
are present as defined in the National Electrical
Code. Failure to comply can result in explosion or
fire.
Depending upon the order specifications, the NWH-18 may or
may not be factory equipped with an AR or other Chromalox
thermostat. Such thermostats function to control outlet tempera-
tures and to limit internal temperatures under abnormal flow con-
ditions. These controls do not fail-safe.
WARNING: Users should install adequate back-up
controls and safety devices with their electric
heating equipment. Where the consequences of
failure may be severe, back-up controls are essen-
tial. Although the safety of the installation is the
responsibility of the user, Chromalox will be glad
to make equipment recommendations.
The NWH-18 series is a general-purpose water or water-based
solution circulation heater intended for use indoors. It is designed
for 150 psig at 550°F per ANSI standards.
The 18 copper-sheathed tubular elements are centered in a 8”
diameter galvanized steel heating chamber and welded to a
removable galvanized steel flange. The assembly is surrounded
by 3” insulation and sheet metal jacket.
INSTALLATION
WARNING: Hazard of Shock. Disconnect all power
before installing heater.
1. Vertical Mounting (Preferred) —
Incorrect
Correct
When the heater is vertically mounted, the terminal housing
will be at the top of the heater. The water 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.
Figure A — Vertical Mounting
Note: A drain pipe located at the bottom of the heater should
be provided and enough room left, when mounting heater, to
allow draining the heater.
© 2010 Chromalox, Inc.
MAINTENANCE
1. WARNING: Hazard of 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.
3. Periodically check temperature control and limit control oper-
ation to insure accurate and safe process operation.
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 con-
nections.
RENEWAL PARTS IDENTIFICATION
Parts Common To All Heaters
Replacement
Element
Assembly
Flexitallic Gasket . . . . . . . . . . . . . . . . . . . . . . . . . . .132-019779-007
Standard Gasket . . . . . . . . . . . . . . . . . . . . . . . . . . .132-017222-007
Model
Volts
Phase
kW
NWH-185015
NWH-185015
240
480
3
3
50
50
155-013185-046
155-013185-047
NWH-187515
NWH-187515
240
480
3
3
75
75
155-013185-049
155-013185-050
NWH-1810015
NWH-1810015
240
480
3
3
100
100
155-013185-052
155-013185-053
NWH-1812515
NWH-1812515
240
480
3
3
125
125
155-013185-058
155-013185-059
NWH-1815015
NWH-1815015
240
480
3
3
150
150
155-013185-061
155-013185-062
NWH-1817515
NWH-1817515
240
480
3
3
175
175
155-013185-064
155-013185-065
NWH-1820015
NWH-1820015
240
480
3
3
200
200
155-013185-067
155-013185-068
Note: When ordering parts for Model Numbers suffixed by “XX” or any other letter or letters not specifi-
cally identified on this instruction sheet, order Renewal Parts on special order basis, giving name of
part, part number, model number and description.
Limited Warranty:
Please refer to the Chromalox limited warranty applicable to this product at
2150 N. RULON WHITE BLVD., OGDEN, UT 84404
TA - U0 - EF
Litho in U.S.A.
Phone: 1-800-368-2493
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