Testing For High Voltage At Power Board; Replacing Performance Light; Replacing A Power Board; Testing The 24 V Transformer - Five Seasons FS-GM20AS-A Owner's Manual

3. Install new APS on plastic spacers. Ensure sensor
protrudes into the airstream.
4. Connect wiring to terminals on APS. Wiring from
power source is connected to terminals 2 and 3.
Wiring to the transformer is connected to terminals 1
and 4.
5. Test the new APS.

Testing For High Voltage At Power Board

A high voltage meter capable of measuring up to
10,000 VDC is required to test the voltage.
1. The Air Cleaner should be ON with the door closed.
The unit fan should be running. The Air Cleaner
should be on at least 5 minutes to allow voltage to
stabilize.
2. Remove cover from electrical compartment.
3. Connect the ground of the high voltage meter to the
ground stud of the power board.
4. Check terminals HV1 and HV2 on the power board to
determine if voltage is present.
5. If no voltage is present, remove both cells from the Air
Cleaner and close access door.
a. Check the voltage at HV1 and HV2 (where
applicable) again.
b. If voltage is present, the problem is with one of
the cells or the copper contact on the high voltage
tray.
c. With a flashlight, look into the cabinet to check
condition of the copper contacts.
d. If the contacts are not bent, replace one cell and
retest voltage. If cell is OK, test the other cell. If
the problem is with a cell, see Troubleshooting
Guide.
e. Check the APS to make sure that it is functioning
correctly.
f. Check the transformer to make sure power is
being supplied to the power board.
6. If there is voltage present, but the performance light
does not come on, replace light.
7. High voltage can be adjusted with high voltage
potentiometer if required.

Replacing Performance Light

Before replacing performance light, turn off power to
the Air Cleaner at the source.
1. Remove the electrical compartment cover.
2. Disconnect the performance light wiring connected to
the terminals on the LED.
3. Push the light out through front of the switch bracket.
4. Push the new light into the bracket.
5. Connect the wiring to the LED terminals.
6. Replace cover.
7. Return power to Air Cleaner. Test light.

Replacing A Power Board

Before replacing power board, turn off power to the
Air Cleaner at the source.
1. Remove the electrical compartment cover.
2. Disconnect wiring from the LED, HV1, HV2 and 24 V
terminals.
3. Remove the hex nut from the power board.
4. Release the power board from the 3 plastic board
spacers, by pinching the end of the spacers and
pulling the board out.
5. Push new board onto spacers. Make sure spacers
click into place to hold down board.
6. Screw on the hex nut saved from Step 3. Ensure the
star washer is in place over the steel spacer for
proper grounding.
7. Reconnect wiring to LED, HV1, HV2, and 24 V
terminals on the new power board.
8. Replace electrical compartment cover.
9. Return power to Air Cleaner. Test power board.
Note: Although the power board has been set before
shipping, it may be necessary to reset the voltage to the
correct load for optimum efficiency. Refer to Testing
Voltage At Power Board section for more information.

Testing The 24 V Transformer

1. The Air Cleaner should be ON. The system fan should
be running. The access door should be closed.
2. Remove electrical compartment cover.
3. Disconnect the leads of the 24 V transformer from the
power board.
4. Measure voltage across leads with a voltmeter.
Voltage should read 24 - 27 VAC.
5. If no voltage present, check operation of the APS.
6. Before replacing transformer, check the resistance of
the power board input. Input should read above 40K
ohms. If resistance is below 40K ohms, the power
board may be the cause of the transformer failure.
7. Reconnect leads to power board.
8. Replace electrical compartment cover.

Replacing The 24 V Transformer

Before replacing 24 V transformer, turn off power to
the Air Cleaner at the source.
1. Remove electrical compartment cover.
2. Disconnect the secondary leads from the transformer
to the 24 V terminals on the power board.
3. Cut the primary leads (to the APS) close to the
transformer.
4. Remove the 2 hex head nuts from the transformer
mounting studs.
5. Remove transformer.
6. Place new transformer over studs and re-install 2 hex
head nuts to secure into place.
7. Connect secondary leads (white) to the 24 V terminals
on the power board.
8. Wire nut primary leads from APS (cut in Step 3) to
primary leads from transformer.
9. Replace electrical compartment cover.
10. Turn on power to the Air Cleaner and test.