Regular Oil Heaters
Chromalox
®
DIVISION
4
SECTION
NWHO
SALES
REFERENCE
DATE
SERVICE REFERENCE
Installation, Operation
and
RENEWAL PARTS IDENTIFICATION
PE426-2
161-058063-001
JANUARY, 2003
(Supersedes PE426-1)
GENERAL
© 2010 Chromalox, Inc.
NWHO(F)-18 Circulation Heaters
(for Regular and Fuel Oil Heating)
FIRE/EXPLOSION HAZARD. This heater is not intend-
ed for use in hazardous atmospheres where flamma-
ble vapors, gases, liquids or other combustible atmos-
pheres are present as defined in the National
Electrical Code. Failure to comply can result in per-
sonal injury or property damage
The NWHO(F)-18 series is a general purpose regular and fuel
oil solution circulation heater intended for use indoors.
The steel-sheathed tubular elements are centered in a steel
heating chamber and sealed into a removable steel flange. The
assembly is surrounded by insulation and a sheet metal jacket.
Depending upon the order specifications, the NWHO(F)-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.
The system designer is responsible for the safety of
this equipment and should install adequate back-up
controls and safety devices with their electric heating
equipment. Where the consequences of failure could
result in personal injury or property damage, back-up
controls are essential.
Specifications — Table A
Fuel Oil Heaters
Dimensions (In.)
Model Volts
Phase
kW
W/In
2
A
B
C
NWHO-1830R15
240 or 480
3
L
L
30
20
53-7/8
32-11/16
29-3/16
NWHO-1840R15
240 or 480
3
L
L
40
20
60-7/8
39-11/16
36-3/16
NWHO-1850R15
240 or 480
3
L
L
50
20
68-1/2
47-5/16
43-13/16
NWHO-1860R15
240 or 480
3
L
L
60
20
78
56-13/16
53-5/16
NWHO-1870R15
240 or 480
3
L
L
70
20
87
65-13/16
62-5/16
NWHO-1880R15
240 or 480
3
L
L
80
20
97
75-13/16
72-5/16
NWHO-1820F15
240 or 480
3
L
L
20
12
53-7/8
32-11/16
29-3/16
NWHO-1825F15
240 or 480
3
L
L
25
12
60-7/8
39-11/16
36-3/16
NWHO-1830F15
240 or 480
3
L
L
30
12
68-1/2
47-5/16
43-13/16
NWHO-1835F15
240 or 480
3
L
L
35
12
78
56-13/16
53-5/16
NWHO-1840F15
240 or 480
3
L
L
40
12
87
65-13/16
62-5/16
NWHO-1845F15
240 or 480
3
L
L
45
12
97
75-13/16
72-5/16
3/4-10 Tap
Mounting
Lugs
2-1/2” Pipe
Outlet
2-1/2” Pipe
Inlet
B
C
A
15-1/8”
