Heating mode sequence of operation

What happens, in order

1. W thermostat contact closes and calls for heat.
2. The control runs safety circuit checks.
3. Induced draft blower runs on high speed for prepurge.
4. Induced draft blower steps to low speed. The low stage pressure switch closes.
5. Igniter warm-up starts once the blower is on low speed and the low stage pressure switch is closed.
6. Gas valve opens at the end of igniter warm-up and flame is established.
7. The control monitors flame presence. The gas valve stays open only while flame is detected.
8. The control runs low or high stage based on its algorithm. After a power cycle the first heat call is high stage.
9. Circulator blower starts on heat speed after the blower on delay and ramps up. EAC terminal energizes with the circulator.
10. If the stage changes from low to high, the inducer, gas valve and circulator all switch to high stage immediately.
11. If the stage changes from high to low, the inducer and gas valve switch to low stage immediately and the circulator stays on high heat for 30 seconds before low heat.
12. When W opens, the gas valve closes and the flame goes out.
13. Induced draft blower runs for post purge, then stops.
14. Circulator continues for the heat off delay. If the last call was high heat, it runs high heat for 30 seconds then low heat for the rest of the delay.
15. Circulator and EAC terminal de-energize when the heat off delay expires and the furnace waits for the next call.

Timings and thresholds

Models

More Goodman furnace sequences

• Normal power-up sequence · Startup
• Dual fuel heat pump to gas furnace transition · Heating
• Cooling airflow ramping profiles A to D · Cooling