ICP Error Code 3: Low pressure switch did not close or reopened (Furnace)
ICP error code 3 on a furnace means: Low pressure switch did not close or reopened. It is also called ICP diagnostic code 3.
Homeowner? What ICP code 3 means for you
Check, then call Your furnace is reporting: Low pressure switch did not close or reopened. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.
Safe things you can check yourself
- Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
- Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
- Make sure the furnace front door or panel is closed properly; many furnaces will not run with the door switch open.
- Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
- Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
- Check that the gas valve next to the furnace is open (handle in line with the pipe). Do not force it.
- Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does ICP error code 3 mean?
Low pressure switch did not prove inducer draft or reopened. If it opens during blower on-delay, blower runs for the off-delay. If it opens within 5 minutes after ignition, the next cycle is limited to maximum heat. Also the expected code when the inducer is unplugged during the pressure-switch safety check.
Applies to: ICP F9MAE / G9MAE modulating variable-speed condensing gas furnaces (060, 080, 100, 120 kBtu/h)
Common causes of ICP code 3
- Wrong vent sizing / restricted vent
- Air leak between vestibule and blower compartment
- Low inlet gas pressure (if LGPS fitted)
A technician checks these and 5 other possible causes on site before replacing any part.
ICP models that use code 3
G9MAE0601714G9MAE0602120G9MAE0801714G9MAE0802120G9MAE1002122G9MAE1202422
Other ICP Furnace codes
ICP code 3: homeowner questions
What does ICP code 3 mean?
Low pressure switch did not close or reopened. Low pressure switch did not prove inducer draft or reopened. If it opens during blower on-delay, blower runs for the off-delay. If it opens within 5 minutes after ignition, the next cycle is limited to maximum heat. Also the expected code…
Is it safe to keep using my furnace with code 3?
It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.
Can I reset ICP code 3 myself?
You can try one reset (power off for 30 seconds, then on). If ICP code 3 comes back, the cause is still there and a licensed technician should check it.
Who can fix ICP code 3 near me?
Aurora Star Tech Inc. repairs ICP furnaces in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.
Homeowner help: Furnace Not Turning On: What to Check · Furnace Blinking Light: What the Flash Codes Mean
Troubleshooting guides
- Blowing cold air All brands · Furnace
- No heat All brands · Furnace
- Short cycling All brands · Furnace
- Check inlet gas pressure ICP · Furnace
- Component self-test ICP · Furnace
- No heat - control does not respond to thermostat ICP · Furnace
- Reading and retrieving status codes ICP · Furnace
Source: ICP (F/G)9MAE Service and Technical Support Manual 440 04 4700 00, Figure 16 Troubleshooting Chart, p.34. 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.