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Dimensions (In.)
Watt
Model Voltage Phase kW
Density
ABC
NWH-3625 1 or 3
Δ 6 47.7 32-15/16 22-1/2 16-1/2
NWH-3925 1 or 3
Δ 9 47.5 32-15/16 22-1/2 16-1/2
NWH-31225 1 or 3
Δ 12 46.2 42-15/16 32-1/2 26-1/2
NWH-31525 1 or 3
Δ 15 45.9 55-7/16 45 39
NWH-31825 1 or 3
Δ 18 45.6 55-7/16 45 39
Chromalox
®
DIVISION
4
SECTION
NWH
SALES
REFERENCE
DATE
SERVICE REFERENCE
Installation Operation
and
RENEWAL PARTS IDENTIFICATION
PE405-6
JULY, 1990
(Supersedes PE405-5)
161-048380-001
GENERAL
INSTALLATION
© 2010 Chromalox, Inc.
Type NWH-3
Circulation Heater
for Water Heating
The NWH-3 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 3 copper-sheathed tubular elements are centered in a 3”
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 NWH-3 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.
CAUTION: 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.
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 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.
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.)
Specifications — Table A
Incorrect
Correct
Figure A — Vertical Mounting
Figure B — Horizontal Mounting
Correct
Incorrect
A
C
B
F
12-5/16”
Thermostat
Type AR
Mounting Lugs
3/8” - 16
Threaded Holes -
1-1/2” Deep
1-1/4” Centers
1” Pipe Inlet
1” Pipe
Outlet
1-3/8” Conduit
Openings
D
240
or
480
E