Gas and Oil Home Heating Furnaces - How Tough?
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TheOaf
02-15-07, 11:11 AM
Of course furnace problems Carrier about 5-7 yrs old (not sure it was in the house when we bought it). Was having problems with the temp so I put in a new thermostat (honeywell) and made a little gap in the rubber boot surrounding the firebox for air flow. The LED error 31 light stopped blinking and it ran ok for about 4 days. Now it is doing the start and stop thing again today and it is only about 61 in the house again my wife said. It has been acting up ever since the "cold snap" of course. I am wondering if it is the pressure switch and how tough that is to change? I am trying to avoid having someone come in and look at it but it would almost be worth it than to be bothered with it every single day...any suggestions from anyone?
DaVeBoy
02-15-07, 06:22 PM
Make sure you have 110 to the furnace. Make sure you have 24 volts coming out of the transformer. Make sure the thermostat 24 volt loop is being completed upon the call for heat. See if the ventor motor works when those things I mentioned, are all in order, as the ventor motor is the first thing that must run.
If the ventor motor does not run, then you could have an issue with the "sequencer" (a relay switch for the ventor). You will not get any 24 volt to the pressure switch, nor any ignition source unless the ventor runs. (Let us know if the ventor runs each and every time you have a call for heat.)
Yes?
Then jumper past every 24 volt safety switch that is wired in series. You could have in this series a pressure switch, flame roll out switch, ventor exhaust gas switch.
You could also test each one of these one at a time, or temporarily bypass with jumper the two wires at each safety switch location, together. But if yo do this and the furnace works...do NOT leave any jumper system on and defeat the purpose of the safety switch! They are all in there for a reason; for your safety!
If the ventor motor does not run, then you could have an issue with the "sequencer" (a relay switch for the ventor). You will not get any 24 volt to the pressure switch, nor any ignition source unless the ventor runs. (Let us know if the ventor runs each and every time you have a call for heat.)
Yes?
Then jumper past every 24 volt safety switch that is wired in series. You could have in this series a pressure switch, flame roll out switch, ventor exhaust gas switch.
You could also test each one of these one at a time, or temporarily bypass with jumper the two wires at each safety switch location, together. But if yo do this and the furnace works...do NOT leave any jumper system on and defeat the purpose of the safety switch! They are all in there for a reason; for your safety!
Grady
02-15-07, 06:22 PM
Pressure switches are easy to change but 90% are changed needlessly. I am not saying they don't fail but not nearly as often as they are changed.
TheOaf
02-16-07, 02:11 PM
well I called in a HVAC guy because it was just getting out of hand, he pulled the rubber line off of the pressure switch and it started draining water and he filled a bucket with it. So he changed the pressure switch and a few other things and now everything runs quite well. There was another part that was plugged so it could not drain. All in all it cost $400 for everything but oh well, at least now the wife is not complaining about it anymore.