Any hvac guys have a way to cross reference a part for me? My heater won’t fire and I’m almost certain the pressure sensor is stuck. I pulled hose and lightly sucked air in it and can’t hear it clicking. Part number: HK05ZZ003 installer shows install date of 2020 written on it. I’m leaving town tomorrow and have dog sitter coming so if I can find one that’ll work today I’d like to fix it.
Got a multimeter? When the inducer fan is running, check continuity on the draft sensor. If it is open, wait until the inducer runs for about 30 seconds then short the wires, and see if it fires. Note that the furnace WILL NOT fire if the draft sensor wires are shorted together BEFORE the inducer has started. Control boards know all your sneaky little tricks…
I can’t even get the inducer fan to kick on. As soon as I turn it on with the thermostat the red light starts flashing. The code says pressure sensor. of are you just saying run it fan mode and then check it not in heat mode.
If the draft sensor is stuck closed, that’s the error it will throw. With everything off check continuity on the sensor.
Thanks man. Just digging into it. Gonna check power to fan then pressure sensor. Appreciate you jumping in to answer.
Fan won’t start without the draft sensor being open. It’s one of the failsafes in the design. Start with checking continuity on the draft sensor switch with the furnace off. If it’s closed, that’s your problem. You can test functionality by disconnecting the switch, letting the inducer fan run then reconnecting the switch (only need to pull one wire off). If it fires up and runs, draft sensor switch is gone to shit. You *might* be able to get it to work temporarily with a little percussive maintenance…
Interestingly I just turned off power to unit, unplugged fan, turned power on and checked continuity to fan and it was fine. I plugged it back in and turned on heat and fucker fired right up and is blasting heat to house.
If this is the first time you’ve flipped the disconnect switch, you just reset the system. After enough failed startups, the system locks out. Be prepared for another failure.
Thanks. I turned off and let it sit for a few minutes and then started it again. Will see if it lasts all week while we’re gone. Will put a new pressure switch in when I get home. Don’t think I’ll be able to get one before leaving tomorrow. Thanks again for walking me through it.
Recently had a similar problem with the shop heater (5 year old Modine "Hot Dawg") - pressure switch was good, but the hose barb on the fan housing was plugged up. A few minutes with the air compressor took care of that.
