Mars Comfort-Aire Century HG Series Installation, Operation & Maintenance Instructions Manual

HG Series Electric Heaters
Installation, Operation & Maintenance Instructions
Overview
The HG Series Auxiliary Electric Heat mounts externally
to the blower outlet of all HE. For the HZ Series it mounts
externally on the horizontals and internally on the vertical
upflow and downflow units. It mounts internally on all
WDG units.Note model compatibility Table 1. Units are
rated for zero clearance at the unit and 1" clearance for
first three feet of duct. The discharge plenum should make
a 90° turn after leaving the unit and be constructed from
non combustible material. The HG electric heat contains a
four stage relay control board which activates the elements
directly via an internally wired low voltage harness. Low
voltage signals (W1 and W2) are staged from the DXM
(AXM on WDG Series) control of the unit.
Figure 1: Typical Vertical External Mount Installation
Electric Heat Assembly
Air Coil
Figure 1a: Typical Vertical Internal Mount
Electric Heat Assembly
Air Coil
Auxiliary Electric Heat
Auxiliary electric heat
power supply knockout
opposite air coil
*
Low Voltage control harness
is prewired on all distributor
class units.
Auxiliary electric heat
power supply knockout
opposite air coil
Low Voltage control
harness is factory installed.
HG Installation - External Mount
1. Disconnect power to the unit.
2. Remove blower access panel(s) from the unit and
control box and element covers from the electric heater.
3. Locate remove and discard blower discharge flanges
from the unit but save the screws. Flanges will be
packaged loose inside the blower compartment of
vertical upflow units and will be factory installed on
horizontal units, downflow units have none. HE036
and 042 units require a transition bracket between
the cabinet panel and the electric heater. This bracket
is packaged inside the blower compartment for field
installation.
4. Position the electric heater as illustrated herein.
Heater control box should be facing the front access
panel of vertical units. For horizontal units notice that
the discharge air opening is off centered in the blower
panel. The electric heater must be positioned so that
its control box is located vertically over the wide side
of this panel.
The electric heater air inlet dimensions should match
the unit air outlet, installer should stop and refer
to the unit/heater compatibility chart later in this
instruction or consult factory if they do not match.
5. Use the saved blower flange screws to attach the
heater by its flanges to the unit panel except do not
fasten flange on control box side.
6. Use aluminum tape (not provided) to seal all four
heater flanges to the blower panel.
7. Locate and route the low voltage control harness
through one of the unit corner post or blower panel
knockout(s). Seal the penetration 'air tight'.
8. Route the control harness through one of the 'pie'
bushings in the heater control box and plug on to the
P2 connector. See figure 3.
9. Install power conduit and attach directly to the
electric heater control box. See figures 5a-c.
10. Replace all covers and panels, heater installation is
complete. Proceed to wiring and setup.