High Efficiency Furnace Problems And Reviews

Question: Why do burners on high efficiency furnace shut off for about thirty second during heating cycle?

(Posted by: Jeff on 2008-12-26 13:01:05)

I have a high efficiency condensing furnace in my home. It heats really well except on really cold days. While running, the burners will suddenly kick off for about thirty seconds and then kick back on. It usually only does this once during a heating cycle. I installed a new thermostat about six months ago and it seems fine. What other reason would cause burners to shut off for short period. The blower runs good and at end of heating cycle shuts off after two minutes. This is normal.

Posted by: DAN THE AC MAN on 2008-12-26, 14:44:29

Sounds like the high temperature limit is opening during long run cycles ...could be normal operation for your furnace,but check the filter,clean or replace it if needed....also,30 seconds sounds too short for a burner to turn off on back on due to a limit opening in most hi-eff furnaces..it usually takes at least a minute for the limit to open,then cool off and re-close ,then control board re-lights burners.....could also be a pressure switch opening during the cycle,,check the intake [if it has one] and exhaust pipe outside to make sure they are clear.......dan

Posted by: M M on 2008-12-26, 13:12:52

It is probably due to the temperature sensor in or around your plenum; if it approaches the shut-down temperature, it will kick the burners off, but allow the fan to run which cools the plenum. It sounds as if your furnace needs an adjustment. I "m not a heating contractor, but I understand that there are limits that are settable. This happened to me and we had a new circuit board installed and it works fine. Ours was not kicking on when the plenum got got and would just shut down. It is not an expensive repair.

Posted by: WDOUI on 2008-12-26, 13:12:56

To let the plenum's heat distribute threw the heat ducts. This is normal with high efficiency furnaces it is just one ot it's cycles. If it did not shut off it would overheat or be less efficient