High Efficiency Furnace Problems And Reviews

Question: High efficiency furnace quit working?

(Posted by: Frank G on 2009-12-29 13:44:07)

Its like the gas is shut off to the burners, ive turned the switch off twice...the main blower will run for about a minute, and then quit........after the big fan quits, the little one runs forever okay, there is a rubber end cap at the exhaust fan assembly....i pulled it off....air blew out, igniter kicked on gas kicked on......plugged flue?

Posted by: DAN THE AC MAN on 2009-12-29, 14:16:13

"gizmoe's " answer good.....additionally---as already stated,most likely the pressure switch isnt closing....when the pressure switch closes it tells the control board that the inducer [ exhaust] fan is on and the vent pipe is clear....if pressure switch doesnt close and the inducer fan is running, most likely the vent pipe or chimney [ if one exists] is clogged somewhere...if furnace is 80% efficient ,uses a metal vent pipe to a chimney,then pull the pipe off of the furnace [ with furnace off] ..check for dead bird down inside the inducer housing or in the vent pipe....also check base of chimney where metal vent pipe connects to it,might need to be cleared......if furnace is 90%+ eff [ uses plastic vent pipe],,check to make sure vent pipe is clear where it exits the house...the end of the pipe [s] could be clogged with snow or ice,,especially if you have had snow lately or someone put unapproved screen over the end of the pipe......fyi,the pipe should never have screen put over it,at least not in the winter....either it should be completely open,,or manufacterers termination kit installed [ concentric rings,etc]..or wire mesh with holes 3/ 8 " or larger........also check the tubing that connects to the pressure switch in the furnace,,make sure it hasnt come off,or split open, at either end.........dan...............******added later***--sounds like you removed a rubber end cap that plugs off the alternative exhaust route,,in case vent needed to be run the other way out of the furnace?....if so,and furnace ran ok...could indicate exhaust pipe is blocked somewhere...also check air intake pipe if one exists,,some 90%+ eff furnaces use an air intake pipe to supply outside air to the burners,,others have open burners that draw air from the area around the furnace... check both intake and exhaust pipes at both ends to the extent possible....and dont run furnace with the rubber end cap removed except for brief testing...sounds like you have a carrier or bryant [ payne,,day / night] brand furnace??,...dan

Posted by: gizmoe on 2009-12-29, 13:53:30

After that it is looking for the pressure switch to close. You could have a plugged port, exhaust plugged, drain plugged causing water to have built up to the point it.s covering the port that the pressure switch senses from or possibly a defective pressure switch. Look for a fault code from the circuit board to help determine what fault it is seeing.

Posted by: johnlamberti@verizon.net on 2009-12-29, 14:00:25

It could be your electronic igntion is bad.....also if it does'nt have electrnic ignition your thermo couple could be bad..............

Posted by: gas man on 2009-12-29, 14:35:10

The best advice u will get today,,,CALL A PRO,u could throw parts at it all day and not fix it,,,i have been repairing these furnaces since they came out and all u can do unless u are a pro is GUESS,,,my exp has been that any time the homeowner trys to fix the furnace it cost twice as much as it should have,,could be as simple as a exaust vent pluged with frost

Posted by: Foggy on 2009-12-29, 15:32:21

Could be something as simple as a contaminated flame sensor. I call it a flame sensor others call it an electronic thermocouple. What it does is send confirmation of ignition back to the control. You can remove the sensor and clean it with steel wool, dry brillo pad, or sand cloth. This handy 2 minute video will maybe save a buck or 2: foggyfacts.blogspot.com/ 2009/ 11/ furnace-auto-ignition-furnace-quick.html