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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Our model DGAA077BDTA is blowing out cold to lukewarm air.

Customer Question

Our coleman model DGAA077BDTA is blowing out cold to lukewarm air. We have checked the ignitor, flame sensor and we have a steady green light. Everything appears to be in order, but will not blow warm air. After about 10-15 min the furnace shuts off as if it has reached the desired temp.
Submitted: 6 months ago.
Category: HVAC
Expert:  airheatman replied 6 months ago.

This sounds like either a problem with gas valve or supply pressure.If LP< are you sure we have sufficient fuel in tank?

Customer: replied 6 months ago.
We do not use propane. I might mention we have a manufactured home (if that makes a difference in the furnace). We use gas for stove, dryer, etc and no problem with these items. I don't believe it is a gas problem. I can see the flame thru the little glass window and it appears to be fine as well.
Customer: replied 6 months ago.
I already opened the ignitor and used steel wool on the flame sensor...all appears well there. One thing I did notice is that with the gas valve (where it goes into the burner area) I was going to use a paper clip to make sure the gas could go thru and it had a sponge like filler in it. Is that suppose to be there? I didn't want to clean it out as I was afraid that is suppose to be there (something like a sealer to keep gas going back?
Expert:  airheatman replied 6 months ago.

If burners are burning a good normal flame., you should be getting heat , no way to be blowing cold air .I am going to opt out to see if someone else may have ideas.