Chromalox DH, DHOC Installation Instructions Manual
Installation Instructions
DH and DHOC
Electric Duct Heaters
PF503
161-562766-001
1
February 2015
Table of Contents
Section Page
General ...............................................................................................................................3
Installation .......................................................................................................................... 3
Mounting ............................................................................................................................6
Wiring ................................................................................................................................10
Operation .........................................................................................................................11
Maintenance ....................................................................................................................11
Heater Bundle Removal and Replacement ................................................................... 11
Replacement Parts .......................................................................................................... 12
Troubleshooting ............................................................................................................... 13
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DH and DHOC Electric Duct Heaters
General
Read and understand all instructions before installing, servicing or operating product. Failure
to do so could result in personal injury or property damage.
These heaters are designed to be installed in either a
horizontal or vertical duct in one of the six positions
shown in figure 12. The heater is constructed with individual metal sheath fintube elements mounted to a
heavy gauge metal terminal box.
Due to the various options and materials available,
check the nameplate attached to the heater terminal
box with the catalog number designation system before installing to insure the heater you received conforms to your specification.
Please read these directions carefully to insure all limitations are properly observed and all wiring and controls are properly installed and connected.
IMPORTANT - Observe at least one complete heating cycle operation before leaving the installation.
FIRE/EXPLOSION HAZARD. 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 personal injury or property damage.
ELECTRIC SHOCK HAZARD. Any installation
involving electric heaters must be performed
by a qualified person and must be effectively grounded in accordance with the National
Electrical Code to eliminate shock hazard.
ELECTRIC SHOCK HAZARD. Disconnect all
power before installing or servicing heater.
Failure to do so could result in personal injury
or property damage. Heater must be installed
or serviced by a qualified person in accordance
with the National Electrical Code, NFPA 70.
Installation
Limitations: Must be in accordance with one of the
following: Standards of the National Fire Protection
Association for the installation of Air Conditioning and
Ventilating Systems of other than Resident Type (Pamphlet 90A) or Residential Type Warm Air Heating and
Air Conditioning Systems (Pamphlet 90B).
NOTE: The minimum distances shown are limitations.
Wherever possible, locate as far away from these limits as practical. In any case, this distance with any required airflow correction must be sufficient to accomplish even air flow at a velocity equal to, at least, the
minimum stated on the heater nameplate.
1. Installation near heat pump, central air conditioner,
filters or humidifier. (Refer to Figure 1).
Duct Heater
Air
Flow
4 Ft.
Min.
Heat Pump,
Central Air Conditioner,
Filters or Humidifier
Figure 1
3
2.
Installation near air handler discharge. (Refer to Fig. 2).
Duct Heater
Air
Flow
5. Installation with duct transitions in some air distribution systems, the duct heater may be considerably larger than the ductwork and the duct area
must be increased by a sheet metal transition. The
slope of the transformation piece on the upstream
side of the equipment is limited to 30° as indicated
in Fig. 5. On the leaving side, the slope should not
be more than 45°.
4 Ft.
Min.
Air Handler
Figure 2
3. Installation in branch duct take-off. (Refer to Fig. 3).
Air Flow
4 Ft. Min. Straight Section
Duct Heater
Figure 3
4.
Installation near turns. (Refer to Fig. 4). If heater must
be installed closer than 4 feet from the downstream
side of a turn, turning vanes must be installed in the
turn. The turning vanes will straighten out the air
flow so it will be uniform over the face of the heater.
2 Ft.
Min.
30"
Air
Flow
Max.
30°
4 Ft. Min.
45°
Duct Heater
45°
Max.
4 Ft. Min.
Figure 5
6.
Do not insulate control or terminal box. (Refer to Fig. 6).
External
Insulation
Top of Duct
Duct Heater
Leave Control
Box Uninsulated
Figure 6
7. Installation in duct larger than heater. For installa-
tion where the duct dimensions exceed the insert
type heater dimensions, the area beyond the heater
dimensions must be filled with wire mesh, expanded or perforated sheet metal of 50% open area as
shown in Figure 7. This will maintain a uniform air
velocity across the face of the duct.
Duct Heater
Here or Here
Air Flow
4 Ft.
Min.
Figure 4
4
Inner Baffle
Insert Type
Duct Heater
Perforated Metal
(50% Open Area)
Flexible Duct
(Must be suitable
for 195°F)
Air
Flow
4 Ft.
Min.
Figure 8
Duct Heater
Remove Bracket and
Use Sheetmetal Screws
Thru Same Holes into Duct.
Oversized Duct
Figure 7
8. Installation with flexible duct. Where a duct heater
must be installed near a flexible duct connection,
be certain that a 4’ minimum distance between the
duct heater and the flexible connector exists and
that the connector is suitable for 195°F temperature. (Refer to Fig. 8).
9. Do not install duct heater outdoors. Duct heaters
cannot be installed with rooftop equipment where
they are exposed to the weather.
10.
Installation with dampers or filters. Maintain at least
4’ distance between duct heater and damper, filter
frames, or other similar obstructions. (Refer to Fig. 9).
4 Ft.
Min.
Damper
Duct
Heater
Air Flow
Top of Duct
Figure 9
Clearance: Zero clearance between duct heater and
combustible materials such as wood is permissible.
However, adequate clearance must be provided around
terminal box for proper ventilation and future service accessibility.
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