INSTALLATION
MOUNTING
NOTE:
All wiring should be installed according to local
and national electrical codes and ordinances.
1. Disconnect electrical power and shut off gas supply
to unit, then remove unit access panels.
2. Mark and disconnect all wires from the existing
control, then remove existing control.
3. Mount 50M56U-751 in the unit using one of the
three mounting options noted in the
Mounting
section. Be certain not to damage any components
such as wire harnesses or blower wheels when
drilling or installing screws.
4. If needed, refer to the
Wiring
section and select
the proper adapter harness needed to replace the
board being serviced.
5. Connect all the wires back onto the 50M56U-751
control board referencing the
Wiring Diagram
section as needed.
6. Ensure all wires are secure to the control board
and unused blower speed wires are attached to
the SPARE terminals. Apply wire ties as needed to
secure wiring.
7. Verify Heat ON delay, Constant Fan Speed, Heat
OFF Delay, and Cool OFF Delay settings, as
described in the
Configuration
section.
8. Reinstall unit access panels and reconnect electric
power. Restore gas supply to the unit.
9. Verify unit operation in heating, cooling, and fan
only mode.
Tabs:
For OEM direct mounting when
replacing controls with a
tray
. Secure with a
½" screw.
Corner Holes:
For OEM direct mounting when
replacing controls with
metal standoffs
. Align
right hand side corner holes with factory sheet
metal hole locations. Secure with 2 1" screws.
Optional: Secure with 2 additional 1" screws on
left hand side (drilling required).
Custom mounting:
Utilize any combination of
½" screws with mounting tabs and 1" screws
with corner holes to secure control. Tabs can
be cut off if additional clearance for mounting
is needed.
NOTE: Start all screws prior to fully
tightening to ensure proper alignment.
A
B
Optional
B
C
A
B
Optional
B
A
B
B
Optional
A
A
3
