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KeepRite · Furnace troubleshooting

No heat, control ignores the thermostat - KeepRite (F/G)9MXT

What is going on

Status light shows a heartbeat but the furnace does not respond to W, Y or G.

Likely causes

  • Thermostat or thermostat cable fault
  • Thermostat not compatible with the control
  • Failed furnace control

Check in this order

  1. Confirm the green light is pulsing (heartbeat) - if not, use the LED codes first.
  2. With a call, measure 24 V at W, Y1, Y/Y2 or G on the board.
  3. No 24 V: check the thermostat and cable.
  4. 24 V present but no response: replace the control.
  5. If a jumper at the board works but the thermostat does not, the thermostat is not compatible: add a ballast resistor, connect the C terminal, or change the thermostat.

Applies to: KeepRite (F/G)9MXT furnaces

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Source: KeepRite/ICP (F/G)9MXT Service and Technical Support Manual 440 04 4321 10, Fig. 16 flow chart, p.24. Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.