ICP Furnace: No heat – control does not respond to thermostat
No heat - control does not respond to thermostat on a ICP furnace: LED heartbeat, no stored codes, but furnace does not respond.
Applies to: ICP F9MAE / G9MAE modulating variable-speed condensing gas furnaces (060, 080, 100, 120 kBtu/h)
Common causes of no heat - control does not respond to thermostat
- Thermostat or thermostat cable fault
- Thermostat not compatible with the control
- Failed furnace control
How to fix no heat - control does not respond to thermostat: step by step
- Check for 24 V at W/W1, W2, Y1, Y/Y2 or G on the furnace control during a call.
- No 24 V: check the thermostat and cable.
- 24 V present but no response: disconnect all thermostat wires and jumper R to W/W1 etc.
- If it works with a jumper, the thermostat is not compatible: add a ballast resistor, connect Com24V to the thermostat, or replace the thermostat.
- If it still does not respond with a jumper, replace the furnace control.
If the unit shows an error code, look it up: ICP Furnace codes
Models
G9MAE0601714G9MAE0602120G9MAE0801714G9MAE0802120G9MAE1002122G9MAE1202422
Source: ICP (F/G)9MAE Service and Technical Support Manual 440 04 4700 00, Figure 16 Troubleshooting Chart, p.33. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.