®
Chromalox
SERVICE REFERENCE
Installation Operation
DIVISION
SALES
4
SECTION NWH
and
(Supersedes PE405-5)
REFERENCE
PE405-6
RENEWAL PARTS IDENTIFICATION
161-048380-001
DATE
JULY, 1990
1-3/8” Conduit
Openings
12-5/16”
1” Pipe
Outlet
Type NWH-3
Circulation Heater
for Water Heating
D
E
Thermostat
Type AR
A
B
C
Specifications — Table A
Mounting Lugs
3/8” - 16
Threaded Holes -
1-1/2” Deep
Dimensions (In.)
Watt
Density
Model
Voltage Phase
kW
A
B
C
1-1/4” Centers
NWH-3625
NWH-3925
NWH-31225
NWH-31525
NWH-31825
1 or 3Δ
6
47.7
47.5
46.2
45.9
45.6
32-15/16
32-15/16
42-15/16
55-7/16
55-7/16
22-1/2
22-1/2
32-1/2
45
16-1/2
16-1/2
26-1/2
39
240
or
1 or 3Δ
1 or 3Δ
1 or 3Δ
1 or 3Δ
9
12
15
18
1” Pipe Inlet
480
45
39
F
GENERAL
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.
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.
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
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.
INSTALLATION
CAUTION: Hazard of Electric Shock. Disconnect all
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.
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.
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.)
The axis of the chamber will be in a vertical position as in
the photo above, and as in Figure A.
Correct
Incorrect
Correct
Incorrect
Figure B — Horizontal Mounting
Figure A — Vertical Mounting
© 2010 Chromalox, Inc.
RENEWAL PARTS IDENTIFICATION
AR2525
Thermostat Assembly
MF7
Model
Volts
Phase
kW
Heating Elements
Thermostat Assembly
NWH-3625
NWH-3625
NWH-3625
NWH-3625
240
240
480
480
1
3Δ
1
6
6
6
6
155-024796-001
155-024796-002
155-024796-003
155-024796-004
300-057560-007
300-057560-007
300-057560-007
300-057560-007
300-048481-006
300-048481-006
300-048481-006
300-048481-006
3Δ
NWH-3925
NWH-3925
NWH-3925
NWH-3925
240
240
480
480
1
3Δ
1
9
9
9
9
155-024796-006
155-024796-007
155-024796-008
155-024796-009
300-057560-007
300-057560-007
300-057560-007
300-057560-007
300-048481-006
300-048481-006
300-048481-006
300-048481-006
3Δ
NWH-31225
NWH-31225
NWH-31225
NWH-31225
240
240
480
480
1
3Δ
1
12
12
12
12
155-024796-011
155-024796-012
155-024796-013
155-024796-014
300-057560-007
300-057560-007
300-057560-007
300-057560-007
300-048481-006
300-048481-006
300-048481-006
3Δ
NWH-31525
NWH-31525
NWH-31525
NWH-31525
240
240
480
480
1
3Δ
1
15
15
15
15
155-024796-016
155-024796-017
155-024796-018
155-024796-019
300-057560-007
300-057560-007
300-057560-007
300-057560-007
300-048481-006
300-048481-006
300-048481-006
300-048481-006
3Δ
NWH-31825
NWH-31825
NWH-31825
NWH-31825
240
240
480
480
1
3Δ
1
18
18
18
18
155-024796-021
155-024796-022
155-024796-023
155-024796-024
300-057560-007
300-057560-007
300-057560-007
300-057560-007
300-048481-006
300-048481-006
300-048481-006
300-048481-006
3Δ
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
AR Mounting Bracket . . . . . . . . . . . . . . . . .027-011378-001 (2)
Flexitallic Gasket . . . . . . . . . . . . . . . . . . . . . .132-019779-001
Standard Gasket . . . . . . . . . . . . . . . . . . . . . . .132-017222-001
Note: Number in ( ) indicates quantity of same part number used.
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
PL - U0 - T3
Litho in U.S.A.
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