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

Donna Ohl, Grady Volunteer Coo · 2008-01-24T06:02:30+00:00

Can you help me troubleshoot my Amana Air Command 80 gas-fired furnace?1. Today it stopped heating the house; three red blinks were visible.The instructions say this means the "pressure switch is stuck open".2. I could see the "top" (smaller" motor wasn't spinning) but the bottom(bigger) motor was spinning; so, I guessed, there was no vaccum to thepressure switch - hence - the pressure switch was stuck in the open (off)position.3. To test, I removed the hose from the top (smaller) motor & sucked on it.4. This self-induced vacuum caused the diaphram to move which caused themechanical switch connected to the pressure valve to close (I could see theswitch move when I sucked on it).5. The flame ignighter heated up and the gas started burning.The three blinking red LED signal went out; I thought I "fixed" my furnace.I cycled the power a few times while I cleaned the filters and blew dustfrom around the wires. But ... 6. Then the Amana Air Command 80 gas-fired furnace stopped heating again;this time, four red blinks were visible!7. Now the opposite ocurred; the "top" (smaller) motor was now spinning butthe bottom (big) motor was not spinning. No air was circulating through thehouse.8. Four blinks indicate an "open Limit Control (primary or auxilliary)".8. If I cycle the power to the furnace, it works for about ten minutes andthen the bottom (big) motor stops spinning and the four blinks start again.I have a few questions:a) How can I troubleshoot this Amana Air Command 80 gas-fired furnace?b) Is there a reset switch somewhere?c) Is there a maintenance guide on the web somewhere?Thanks,Donna

Jan 24, 2008 48 Replies

Rate this thread:

Bubba 18 years ago

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

Vote

Bubba 18 years ago

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.

Vote

Donna Ohl, Grady Volunteer Coo 18 years ago

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

Vote

Stormin Mormon 18 years ago

Yes, that's quite dirty.

Vote

Stormin Mormon 18 years ago

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

Life is nearly complete. One out of three.

Vote

Brent 8 years ago

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

Vote

rooster 8 years ago

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

Vote