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(Supersedes PE429)
PE429-1
NWHO
161-058065-001
FEBRUARY, 1986
4
and
Installation, Operation
RENEWAL PARTS IDENTIFICATION
Type NWHO-45, 72, 108
Circulation Heaters for
Regular and Fuel Oil
Heating
© 2010 Chromalox, Inc.
Dimensions (In.)
No. 3Ø
Model Volts 3Ø kW Circuits A B C D E
NWHO-4590 240 or 480 90 5 72
1
/2 25
1
/2 63
5
/8 18
13
/16 12
1
/2
NWHO-45125 240 or 480 125 5 87
1
/2 25
1
/2 78
5
/8 18
13
/16 12
1
/2
NWHO-45150 240 or 480 150 5 102
1
/2 25
1
/2 93
5
/8 18
13
/16 12
1
/2
NWHO-45175 240 or 480 175 5 117
1
/2 25
1
/2 108
5
/8 18
13
/16 12
1
/2
NWHO-45200 240 or 480 200 5 125 25
1
/2 116
1
/8 18
13
/16 12
1
/2
NWHO-77220 240 or 480 200 6 97
1
/2 27
3
/4 88
5
/8 19 13
3
/4
NWHO-77225 240 or 480 225 6 105
1
/2 27
3
/4 96
5
/8 19 13
3
/4
NWHO-77250 240 or 480 250 6 113
1
/2 27
3
/4 104
5
/8 19 13
3
/4
NWHO-108300 240 or 480 300 6 98
1
/2 29
1
/2 89
5
/16 19
3
/8 14
1
/2
NWHO-108325 240 or 480 325 6 104
1
/2 29
1
/2 95
5
/16 19
3
/8 14
1
/2
NWHO-108350 240 or 480 350 6 110
1
/2 29
1
/2 101
1
/16 19
3
/8 14
1
/2
Specifications – Table A
GENERAL
The high capacity NWHO-45, 72 or 108 series are intended for
indoor use and are used primarily for oil heating.
The 45, 72 or 108 steel sheathed tubular elements are centered
in a 14”, 16” or 18” diameter steel heating chamber, respectively,
and welded to a removable steel flange. The assembly is sur-
rounded by 2” of insulation and a sheet metal jacket.
Depending upon the order specifications, the NWHO-45, 72 or
108 may or may not be factory equipped with an MF2 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.
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 essen-
tial. Although the safety of the installation is the
responsibility of the user, Chromalox will be glad to
make equipment recommendations.
INSTALLATION
1. Vertical mounting (axis of chamber
vertical) is preferred. Check factory
for constructions suitable for hori-
zontal mounting.
2. Mount heater with terminal enclo-
sure at top, and use lower nozzle as
inlet to the circulating fluid.
3. The NWHO-45, 72 and 108 series
of circulation heaters are provided
with mounting lugs to support the
heater chamber. Refer to Figure A
for one suggested mode of support.
4. Mount heaters to permit unre-
strained expansion of chamber due
to temperature. The large flange lug
should be bolted solidly; however, the remaining lug should be
bolted loosely to allow freedom of movement with expansion.
5. DANGER: Hazard of Fire. Provide minimum of 6” spac-
ing from chamber and related piping to nearest combustible
material. Avoid operation of heater near combustible fluids or
in combustible vapor or gas laden atmosphere. Note: Contact
factory for heaters suitable for use in hazardous locations.
6. Provide adequate space at terminal end to permit withdrawal of
the heater from chamber should servicing be required.
7. If two or more heaters are needed to provide the needed heat-
ing capacity, arrange them for series flow.
8. DANGER: Possible Explosion. A pressure relief valve
should be provided by customer at outlet of vessel. There
should be no valving between vessel and relief valve.
6” Outlet
Temperature
Control
C
Mounting
Lug Centers
8
13
/16”
D
A
6” Inlet
5 Conduit
Outlets
72° Apart
or
6 Conduit
Outlets
60° Apart
Figure A
2 x
3
/4”
Slot
1”
E
B
These Dimensions are typical. Check factory for dimensions of a particular unit.