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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 (L1-L2)
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). Button
down – summer mode.
4. Check Z2 (Hi-Lo flame and fan speed switch)
Button down - Minimum velocity
Button up – Maximum velocity
Troubleshooting Step 2
Point 3 (Z1)
Z1 is down (closed) but there is no voltage on the fan
motor M.
Check wiring 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 (lower than 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 (Manual-program mode
switch).
Button up – manual mode.
Button down – automatic mode.
7. Check M2 (Fan thermostat).
The thermostat is closed only when its
temperature is higher than 104 °F.