Amana Air Command 80 Gas Fired Furnace (4 blinks) troubleshooting

[Donna Ohl, Grady Volunteer Coo]

On Wed, 30 Jan 2008 05:53:50 -0700, Donna Ohl, Grady Volunteer Coordinator wrote: I learned a lot but I still would like to know if I can ask some questions.

I posted a picture of the "evaporator coil" before cleaning here:

QUESTION 1: (see picture 1) Why is there an "evaporator coil" in a heating system? Is it only because it shares the same ductwork with the A/C? It seems to be a weak link with respect to the dust that gets past the filters.

QUESTION 2: (see picture 2) I don't see how I can get to the bacterial pad he put near the coil. Are they supposed to last forever? I don't see how they can but I don't see how I can replace it myself. Did I miss something?

QUESTION 3: (see picture 3) Does that evaporator coil cleaner actually work more than a short while? Bacteria can gro back real soon, so I was wondering if that disinfectant actually works over the long term.If not, where do I spray it now that I have a full can of it?

Thanks for your help, Donna

[Bubba]

Well, its a shame he didnt check the temp rise. He obviously was too lazy or in a hurry or something. Temperature rise is a range of temperature that your furnace is designed to be used at. Look at the rating plate info inside the furnace. It will probably show 35-65 or

40-70. Measure the temp coming in the furnace return closest to the blower. Measure the temperature coming out of the furnace about a foot away from the supply plenum (where it wont see the radiant heat). The difference between those temperatures should fall within the range listed on the furnace rating plate. Too high (above the 65 or 70) and you risk repeatedly replacing operating controls and heat exchangers. Too Low and the air will feel cold coming out of the registers.

Bubba

[Bubba]

Answers:

1) If you didnt have an evaporator coil, you wouldnt have cool air in the hot summer. Its not a weak link. You need to replace filters regularly, use quality filters and make sure there are no gaps in the return ductwork after the filter. If the ductwork is not sealed air tight, the furnace will suck dirty unfiltered air into the furnace. It gets on the motor (causing bearing failure), it gets on the blower wheel (causing reduced air flow) it gets on the secondary heat exchanger (causing reduced air flow) and it gets on the cooling coil (and youve seen first hand what that does and costs. A box of filters and a tube or two of caulk is certainly cheaper than $400 in repairs and whatever extra it has been costing you to run a furnace that wasnt operating efficiently.

2) No, the pads dont last forever. Probably just for the cooling season and then needs to be replaced. Find out from your technician or from

3) As far as the cleaning, it will stay clean now till you let dirt back in. Disenfectant? Probably wont last much longer that a few heating or cooling cycles. But it certainly doesnt hurt to clean and disinfect at the same time. You need to be trained in your spraying technique. It takes 4 years to get it right. :-)

Bubba Calgon's website.

[Donna Ohl, Grady Volunteer Coo]

I'll see if I can check the temp rise. He was only here about an hour, certainly no more ... so I guess he *was* in a hurry! :)

Anyway, the photos I referenced show what it was.

I've got to get back to work but I'll post some photos of the entire unit 'cuz I have some questions about what he did (I didn't watch the whole thing so I wasn't sure but I'm very curious now).

I'll open a separate thread on that.

I thank you, Bubba especially, for taking the time to help out a fellow human being!

Donna

[Stormin Mormon]

Yes, that's quite dirty.

[Stormin Mormon]

1) Bubba helps someone 2) See Paris 3) Grand children

Life is nearly complete. One out of three.

[Brent]

replying to Donna Ohl, Grady Volunteer Coo, Brent wrote: My furnace has been working great, but today it won?t work at all. I? am getting nothing

[rooster]

replying to Donna Ohl, Grady Volunteer Coo, rooster wrote: I believe the complexity of the mechanism may be beyond the skill of a novice and tampering could result in a catastrophic failure such as a house fire and that may be why there are no DIY instructions

[trader_4]

Sadly Donna died in a house fire 10 years ago. What's wrong with you Home Moaners?