Question regarding diagnostic code on recently installed York GY9 series gas furnace

[osx-addict]

Hi all..

We had a remodel done a bit over a year ago and the other day it was a bit cool so I turned on the furnace.. Anyway, it would run for a bit and then shutoff and that was the end of it.. After a while I noticed it wasn't warming the house so I popped up into the attic and removed the front panel from the furnace and power cycled it. After it started up a bit it stopped again and started blinking the diagnostic LED 6 times in the color red. Below is the statement I found in the users guide for this readout :

6 RED FLASHES: This indicates that after the unit was operating, the pressure switch opened 4 times during the call for heat. If the main blower is in a “Delay on” mode it will complete it, and any subsequent delay off period. The furnace will lock out for one hour and then restart.

So, I guess I'm hoping that someone could explain to me what the above statement means.. While I am a software engineer in my day job, the above makes no sense to me.. Is it complaining about a gas issue or condensation issue or fan issue or ????

Many thanks in advance!

[MaintenanceMan]

Your furnace has an exhaust fan. It's the first thing you hear when the furnace comes on. The pressure switch insures that the exhaust fan is running. That code could mean that the exhaust pipe is blocked or the intake pipe could be blocked. Some condensation could of gotten into the the switch itself. The switch itself could of course be bad. Or there could be a problem with the exhaust blower. Or even some other problems.

At any rate, your switch is opening up during operation or maybe not even closing and preventing the furnace to cycle. There are several things to check. That part should be under warranty at less than a year old. I would recommend you call your installer.

[osx-addict]

Thanks for the info.. I will likely call them.. Interestingly enough, I tried it again the other night and it ran just fine for about 15-20 minutes.. The house started getting a bit too warm and I shut it down -- haven't tried it since..

[jadnashua]

You might want to look outside at the exhaust/intake and make sure it isn't plugged with either snow, ice, or something else. On a really cold day, you could have problems with the intake or potentially the exhaust. Also, if any of the pipes have a leak, it would detect a problem with the flow and or pressure and shut down.