Troubleshooting
Starting Sequence (Electrical)
Step 1
1.Check L1 – L2 (Supply 120 V, 60 Hz)
2.Check M9 (Main fuse)
Troubleshooting Step 1
Point 1
No voltage (120 V).
Check the electrical supply line, wiring and connections.
Point 2 (M9) Fuse damaged.
Check the electrical supply line and replace the fuse.
Summer Mode
Step 2
3.Check Z1 (Reset summer/winter switch). The switch is closed if there is no ignition block.
4.Check Z2
Button up – Maximum velocity
Troubleshooting Step 2
Point 3 (Z1)
Z1 is open and no ignition.
Check wirings and connections. If everything is okay, replace the switch.
Point 4 (Z2)
Z2 is down but the fan motor runs at the maximum velocity (120 V).
Z2 is up but the fan motor runs at the minimum velocity (<120 V).
Check wiring and connections. If they are okay, replace the switch.
Winter Mode
Step 3
5.Check Z1 (Reset summer/winter switch).
Button up – winter mode.
6.Check Z3
Button down – automatic mode.
7.Check M2 (Fan thermostat).
The thermostat is closed only when its temperature is higher than 104 °F.
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