Tweet
I have a Bryant 90 Plus forced air heating system. It has an odd problem that I would like advice on.
When it is very cold outside the furnace gets into a cycle that shuts down its ability to heat the house. When it's in this cycle the thermostat is calling for heat constantly of course. The burner will come on and burn for a while and then shut down. The combustion blower keeps running constantly. I notice that inside the combustion blower I can hear the noise of water sloshing about, like it's not draining properly.
If I shut the furnace off the water quickly drains out normally (the drains are clean and clear). When I restart the furnace it starts normally and will run for a while, then the water noise returns and the burner shuts down. Of course when in this condition the house won't heat properly and the combustion burner never stops running, and the water sloshing will not go away until I manually shut off the furnace.
If the outside temperature is not constantly in the low twenties outside the furnace never gets into this situation and works fine. When in the low twenties outside I can heat the house if I manually shut off the furnace briefly every half hour or so.
As I've noted the drains are clear and the inside of the combustion blower case is clean and it's bottom drain is clear.
It appears that the blower squirrel cage is pushing water up the inside of the fan case when running and trapping water. Eventually this water is enough to cause the pressure switch to cut the blower off as it "thinks" there is no or improper combustion blower air flow. If I remove one the tubes to the pressure switch, the furnace behaves the same, blower on burner off.
Before I try replacing the pressure switch I would like to know if anyone has encountered a problem like this and what they did to fix it. Also expert opinion would be appreciated.
When it is very cold outside the furnace gets into a cycle that shuts down its ability to heat the house. When it's in this cycle the thermostat is calling for heat constantly of course. The burner will come on and burn for a while and then shut down. The combustion blower keeps running constantly. I notice that inside the combustion blower I can hear the noise of water sloshing about, like it's not draining properly.
If I shut the furnace off the water quickly drains out normally (the drains are clean and clear). When I restart the furnace it starts normally and will run for a while, then the water noise returns and the burner shuts down. Of course when in this condition the house won't heat properly and the combustion burner never stops running, and the water sloshing will not go away until I manually shut off the furnace.
If the outside temperature is not constantly in the low twenties outside the furnace never gets into this situation and works fine. When in the low twenties outside I can heat the house if I manually shut off the furnace briefly every half hour or so.
As I've noted the drains are clear and the inside of the combustion blower case is clean and it's bottom drain is clear.
It appears that the blower squirrel cage is pushing water up the inside of the fan case when running and trapping water. Eventually this water is enough to cause the pressure switch to cut the blower off as it "thinks" there is no or improper combustion blower air flow. If I remove one the tubes to the pressure switch, the furnace behaves the same, blower on burner off.
Before I try replacing the pressure switch I would like to know if anyone has encountered a problem like this and what they did to fix it. Also expert opinion would be appreciated.
Comment