Furnace problem...solution per contractor...please take a look

gone_fishing · 12-01-2008, 09:36 AM

Quick summary...I have a 14 year old York gas, forced hot air 4 ton heater. Last winter the "Rollout open" switch would trip on us. This was during my renovation in that room. It was cleared up and we had no problems until this fall. Our HVAC guy came out and replaced the switch. I changed the filter and we had no problems for about 3 weeks. Then it starts tripping again. There is no obvious cause. It does seem to happen 90% of the time between 2am and 7am. Our HVAC guy said we need to replace the furnace as it is bad. He couldn't give me a definite answer as to the cause. I called out 4 other companies for bids on the heaters. The first 3 gave me bids agreeing the the system was shot. They didn't look into the problem at all. The fourth came out and looked into the problem. He was a mechanic and not a salesmen. He said our problem could have stemmed from leaks in the return air ducts, paired with walling in the heater area, using a 3M filter (restricted flow) and a lack of chimney cap.

Therefore, I capped the chimney today, taped the heck out of the ducts, and changed the filter.

Does this sound like it could be part of the problem? My view is to give it a week or two to make sure it doesn't trip. After all, this guy did talk himself out of a furnace sale. He stated that the big shops are struggling for business right now and looked at me as an easy job.

hvac122 · 12-01-2008, 12:10 PM

Usually the rollout switch will trip from having the flames rollout for some reason or the other. Where is the furnace lacated in the house? If your returns were restricted by the 3m filter and drawing from the holes in them this could have caused your furnace room to go into a negitive pressure and draw the flames out. Its hard to say from here without more information. Also the lack of a chimney cap and windy conditions could have caused the same thing.

I would highly recommend getting rid of the 3m filters. They have killed more furnaces around here than I can remember. They are much to restrictive (even new) and most duct systems are not designed for that.

Any of the service techs that you had out should not have only told you that your furnace was bad but also explained what was bad. The salesmenn wouldn't have been able to do this.

Hopefully the last guy out (more than likely on a free estimate) will get compensated from you if his repairs work.

biggles · 12-01-2008, 05:48 PM

do a visual when the burner comes on right before the fan starts....you don't want to see any flame waves/rollouts as the fan pressurizes the heat exchanger to send the heat into the space.if you see no change on the flames as the fan runs it gives you clue to the integraty of that HEAT-X.if it is all over the place with the fan start your HEAT-X is leaking .if they are not showing you why you need a 100% changeout they are pushing parts on you and not solving the rollout.

**beenthere** · 12-01-2008, 06:06 PM

Where does teh furnace get its combustion air from, now that you closed it off from the rest of the house/basement.
You may need to add a combustion air intake.
Or transfer grilles in the wall so it can pull air from the rest of the basement.

hvaclover · 12-01-2008, 06:10 PM

Usually the rollout switch will trip from having the flames rollout for some reason or the other. Where is the furnace lacated in the house? If your returns were restricted by the 3m filter and drawing from the holes in them this could have caused your furnace room to go into a negitive pressure and draw the flames out. Its hard to say from here without more information. Also the lack of a chimney cap and windy conditions could have caused ////////////////////////////////////////////////////////////////////////////////xx
That's for sure!

gone_fishing · 12-01-2008, 06:40 PM

Sounds like we have a winner...the furnace is on the ground level of a split level in the middle of the home. I installed a bi fold door that is slotted for additional air. There was a negative pressure problem. It only tripped 1x from when I taped it up yesterday. Today I did the rest of the work so hopefully this lasts the week so I can cross new furnace off my Christmas list!

Yes, he will be compensated. I am closing in part of my garage. I've already asked him to come back and run duct work and redo the return duct that is in that room. IN ADDITION, my in-laws have a 60+ year old furnace that they are finally replacing. It's giving them trouble for the first time in the 25 years they have lives in their home. I have recommended him to them.