19
3. Position duct covers as shown below. The supply duct
cover is installed ( insulation side down )over the
downflow return opening by engaging one side of the
panel under a retaining angle and securing the other
side with 3 screws.
Note: If unit is equipped with Return Air Smoke
Detector refer to field conversion for horizontal
discharge before installing return air duct cover.
4. Slide return duct cover ( insulation side up ) into supply
openings until endward edge of the duct cover engages
with the 2 retaining clips on the duct flanges. Secure the
outward edge of the each duct cover with 2 screws.
Note: The following units require a limit switch
change out. The additional limit switch is shipped
attached to the blower housing for these models.
Proceed to Step 5 for the following models "ONLY".
Y*C072A**(H,Z), YSC090A**(M,Y), Y*C092A**(M,Y),
YHC092A**(H,Z), Y*C102A**(M,Y), Y*C102A**(H,Z),
Y*C120A**(M,Y), Y*C120A**(H,Z).
5. After completing installation of the duct covers for hori-
zontal discharge, proceed to TCO-A instructions.
TCO-A Instructions:
If the unit being installed is listed in the following table the
limit control TCO1 must be replaced with the extra limit con-
trol shipped in the heater compartment. Replace TCO1 fol-
lowing the instructions in steps 1through 3 below. If the unit
being installed does not correspond to any in the following
table, skip steps1 through 3 and go on to next step in the in-
stallation process.
Installation
Y*C092A**(M,Y), YHC092A**(H,Z),
Y*C102A**(M,Y), Y*C102A**(H,Z),
Y*C120A**(M,Y), Y*C120A**(H,Z)
Unit Model Number
Y*C072A**(H,Z), YSC090A**(M,Y),
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote discon-
nects before servicing. Follow proper lockout/tagout pro-
cedures to ensure the power can not be inadvertently en-
ergized. Failure to disconnect power before servicing
could result in death or serious injury.
1. Remove the heat section access panel.
2. Remove TC01 from shipping location, attached to the
combustion blower.
3. Replace and discard the existing TC01 originally installed
at the factory for downflow operation with the TC01
shipped attached to the combustion blower for horizontal
operation.
4. Replace heat section access panel.
Return Air Smoke Detector
The factory installed Return Air Smoke Detector is installed
in the Downflow discharge position. No additional field
setup is required.
If a unit is to be converted to Horizontal discharge, the fol-
lowing conversion must be performed:
1. If the unit has an economizer, it must be pulled out in the
operating position.