Chromalox NWH-185015 User Manual
(Supersedes PE424)
PE424-1
NWH
161-058005-001
APRIL, 1999
4
and
Installation, Operation
RENEWAL PARTS IDENTIFICATION
INSTALLATION
GENERAL
© 2010 Chromalox, Inc.
Type NWH-18 Circulation
Heater for Water Heating
(150 Pound Construction)
WARNING: Hazard of 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 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.
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.
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.
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.
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 temperatures and to limit internal temperatures under abnormal flow conditions. 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 essential. Although the safety of the installation is the
responsibility of the user, Chromalox will be glad
to make equipment recommendations.
Specifications — Table A
Dimensions (In.)
Model
Volts Phase kW W/In
2
ABC
NWH-185015 240 or 480 3 50 42 457/8 2411/16 213/16
NWH-187515 240 or 480 3 75 45 537/8 3211/16 293/16
NWH-1810015 240 or 480 3 100 49 607/8 3911/16 363/16
NWH-1812515 240 or 480 3 125 50 681/2 475/16 4313/16
NWH-1815015 240 or 480 3 150 50 78 5613/16 535/16
NWH-1817515 240 or 480 3 175 50 87 6513/16 625/16
NWH-1820015 240 or 480 3 200 50 97 7513/16 725/16
3/4-10 Tap
Mounting
Lugs
2 1/2” Pipe
Outlet
2 1/2” Pipe
Inlet
B
C
A
151/8”
Incorrect
Correct
Figure A — Vertical Mounting
Heater Model 240V 3 Phase Fig. 480V 3 Phase Fig.
NWH-185015 1 2
NWH-187515 1 2
NWH-1810015 1 2
NWH-1812515 1 2
NWH-1815015 1 2
NWH-1817515 1 2
NWH-1820015 1 2
OPERATION
1. Do not heat solutions that are corrosive to the heating element
sheath or the heating chamber.
WARNING: Type NWH Circulation Heaters are
equipped with copper heating elements and
galvanized-steel heating chambers. It is the
responsibility 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 corrosive effect of the solution
upon the heating elements and chamber.
Chromalox cannot warrant any electric circula-
tion 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 insulation. Liquid-tight terminal enclosures are available to protect
heater. Check Factory.
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.
WARNING: Hazard of Shock. Any installation
involving electric heaters must be effectively
grounded in accordance with the National
Electrical Code to eliminate shock hazard.
1. Be sure line voltage matches heater voltage (on nameplate).
2. Electric wiring to heater must be installed in accordance with
local and National Electrical Codesby a qualified person as
defined in the NEC.
3. Power controllers must be used when heaters are rated for 480
volt service or if the amperage rating of the heaters exceeds
the contact rating of the thermostat.
4. Refer to Wiring Diagram Table B for the proper wiring diagram for connecting heater.
WIRING
Note: Dotted lines indicate “customer furnished.” However, Thermostat can be furnished by Chromalox if so specified on the order.
INSTALLATION
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)
3. Whether vertically or horizontally, the heater should be rigidly
mounted so that vibration is at a minimum since excessive
vibration will result in erratic thermostat operation. The
NWH-18 is provided with mounting lugs to support the heating chamber. (See photo on previous page)
4. By using a slotted mounting assembly on either of the mounting lugs, the heater chamber will be permitted to expand with
increasing temperature.
5. DANGER: Hazard of Fire. Provide minimum of 6” spacing from chamber and related piping to nearest combustible
material. Avoid operation of heater near combustible fluids or
in combustible vapor or gas laden atmospheres.
6. Provide adequate space at terminal to end permit withdrawal
of the heater from chamber for servicing.
Table B — Wiring Diagrams
L1
L2
L3
Contactor
Contactor
Contactor
Thermostat
120V or
240V
120V or
240V
L1
L2
L3
Contactor
Contactor
Contactor
Thermostat
Figure B — Horizontal Mounting
Correct
Incorrect
Figure 1 – 240V 3-3 ø Figure 2 – 480V 3-3 ø
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