HVACopediaICP · Furnace
8 Gas heating lockout
What the control is telling you
Control does NOT auto-reset. Turn off power, wait 5 minutes, retry.
Applies to: ICP F9MAE / G9MAE modulating variable-speed condensing gas furnaces (060, 080, 100, 120 kBtu/h)
Likely causes
- Gas valve relay on control stuck closed
- Miswire or short to the gas valve BLUE wire
Test and repair steps
- Warning: Gas valve may be powered when it should not - verify gas valve closes.
- Turn power off and wait 5 minutes before retrying.
- Check the BLUE gas valve wire for miswiring or a short.
- If the code repeats, replace the furnace control (stuck relay).
Models that show this code
6 models in ICP (F/G)9MAE Modulating Furnace
Other codes on the same units
- 5 Abnormal flame-proving signal
- 6 Ignition proving failure
- 6+1 Ignition lockout
- 7 Limit circuit lockout
- 9 Medium/high pressure switch or PSR relay did not close or reopened
- 10 Line voltage polarity
- LED off Amber status LED off - no power / blown 3 A fuse
- LED steady ON Amber LED on solid - control lockout / wrong model plug
Save it for the next call
Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.
Source: ICP (F/G)9MAE Service and Technical Support Manual 440 04 4700 00, Figure 16 Troubleshooting Chart, p.35. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
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.