Lennox Furnace Model# G32Q3-75-3

[reeno343]

Hi everyone!  This site has been very helpful in the past and I'm hoping you can come through for me again.

I have a Lennox gas furnace.  I noticed my house was pretty darn cold this morning and saw that the thermostat was set at 68 but the temperature was only at 63.  I went down to the furnace and flipped the switch off and back on.  The furnace began it's cycle but I did notice a sound that I can only describe as "gurgling"  like there is some water where there shouldn't be.

It starts up, I see the ignitor glow, I see the flames come on, the blower starts.  After a little bit the flames go out but then they come back on.  Then sometimes the blower stops for a couple seconds and starts up again.  It keeps blowing warm air enough to warm the house a little bit but then shuts off completely.  Any ideas?  I wanted to try cleaning the flame sensor but I don't know where to find it.  Thanks in advance. 

[reeno343]

I also forgot to add that the LED surelight system is flashing an alternating slow flash, which in the manual indicates an ignition problem. But when I turn it off, wait a little bit, then turn it on again, it flashes simultaneously fast which is telling me that it is in normal operation and is receiving a heating signal from the thermostat. But after a few minutes, it repeats the cycle of that wierd "watery" sound, then the cutting out for a second, etc. Once completely shut off again it gives the alternating slow flash signal again.

[RegUS_PatOff]

ALTERNATING SLOW FLASH              ALTERNATING SLOW FLASH

Watchguard −− burners failed to ignite;

OR limit open more than 3 minutes;

OR lost flame sense 5 times in one heating cycle;

OR pressure switch opened 5 times in one heating cycle.

Lennox Furnace G32Q3 Service Manual

[applianceman18007260692]

You have water in the draft inducer fan housing. The hose that goes from draft inducer fan to pressure switch also. You need to get it out. Must be rain water coming into to the fresh air supply to the inducer housing. Better check that.

[dkpd1581]

If you have a 90%+ efficient furnace (you can tell because it uses PVC piping for the flue - ie exhaust piping) you have an improperly pitched flue.  The escaping gas still has moisture and is being trapped in some lateral section of the flue.  Your installation could have settled or shifted over the years and now you have an unintended trap.  The exhausted flue gasses from the furnace cannot overcome the weight of the water trap and will cause the unit to shut down due to the inducer proving pressure switch opening the 24VAC safety circuit.

This moisture needs the proper pitch to be sent back to the heat exchanger via the PVC flue and ultimately to the condensate pump for later removal.  Two ways to fix the problem are:

1. Correct the pitch of the flue

2. Find the low spot, drill the PVC, insert a fitting in the hole and use a vinyl tube arrangement to direct the condensate back to the unit/cond pump. 

I have done #2 several times when it was impossible to correct the pitch of the flue.  I use a brass barb fitting to insert into the hole drilled in the low spot.  The barb is held securely with some JB Weld.  I then use 1/4" vinyl tube and make a small P-trap type bend in the tubing to create a water lock - using tape to keep the tubing in the loop shape (not doing so will allow flue gasses to pass through the tubing and enter the conditioned space - a bad thing!!).  Then just direct the tubing to the condensate line going to the unit's condensate pump.

[applianceman18007260692]

cool