Goodman GMH95 too HOT>>>


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Old 01-12-10, 03:43 PM
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Goodman GMH95 too HOT>>>

I just installed a new furnace in my new home. The heat at the register is getting up to 150 degrees. I have checked and adjusted the pressure at the input and output of the regulator. The flame at the base looks blue but turns more orange/yellow inside the heat exchanger. I'm not sure if the flame is too hot or the air flow is too restricted. Any help will be appreciated....
 
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Old 01-12-10, 04:25 PM
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problem

back in the old days,you could just take an old furnace out,and put another one in,without much thought.today.you have to check the furnace nameplate for s the specified temperature rise.example temp rise-35degrees to 65 degrees.you then need to check the temperatures of the return duct and the supply duct and see if you are within the range. if you are running too hot,say maybe 70 degrees temp rise,you need to adjust the blower speed to move more air across the heat exchanger.if you are at max speed on the blower,and stil too hot,you either have too small of a ductwork system,or the furnace is oversized.you need to match the ductwork and the cfms of air to the furnace.
 
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Old 01-12-10, 05:10 PM
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I agree with seabee ---- you need a competent repairman to set up the furnace properly for you. Unfortunately, this takes more skill than you have judging from your comments.
 
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Old 01-12-10, 05:18 PM
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Did you do all the installation work literally yourself?

If one does do that and say the person is not a certified furnace installer, I wonder how certain states treats this when it comes to home insurance. And I wonder what this does for any warranty that the furnace mfg'er gives.

Natural gas or propane? And was the furnace recieved already set up to the fuel type?
 
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Old 01-12-10, 05:23 PM
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Seabee570..Thanks for the insight. I think your right about the duct system, which I also installed, might be the problem. The house is about 2200 sq ft and the furnace is 90K. I set it up as a dual fuel system and installed a 3.5 ton 13 seer heat pump as primary. My concern with the furnace flame is that is looks a little more orange/yellow down inside the heat exchanger tube than what I've seen on a 80% furnace. Is that normal for a 95%?
 
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Old 01-12-10, 05:43 PM
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Even a skilled repairman cannot reliably observe a burner flame and know that it's correctly adjusted.

Usually new furnaces come set so they will burn safely. Why you changed those initial settings is unclear, but now there is no reason to believe that the furnace is operating safely or properly. Indeed, it probably is not since the furnace is apparently overheating.

Call a repairman to have the furnace set up properly.
 
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Old 01-12-10, 05:51 PM
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ECMAN..Thanks for your response. I am not a certified installer. Over the years I have installed a few HVAC systems and repaired a bunch. As for insurance and warranty. In the county I live in, you are allowed to do your own HVAC, electrical, plumbing etc on your own house. I did all of that work on my new house, as I have in the past, and I was inspected on each. I of coarse cann't do the refregerant. The furnace is new and the warranty will probably not be valid. It was shipped set up for Natural gas. I converted it to LP with a supplied kit. I do have a manometer and did check and adjust the pressures. Initially I did the sizing study but did not calculate the cfms delivered and returned. I did look up the temp. rise per spec sheet which was 35-65 degrees. I measured the return and supply and found the rise to be outside the limit at about 78 degrees. I just don't know if the excessive heat is due to constricted air flow or the flame burning to hot. Thanks..
 
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Old 01-12-10, 07:18 PM
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furnace

like seattle said.most furnaces are in the ballpark when coming from the factory.i do not see why you are obsessed with the flame.the furnace must be matched to the load=duct size=cfm+btus=heat load. if the flame is off,one way or another,it is most likely not going to have the affect that you are seeing. the furnace is either too big,or the ductwork too small or a combination of both.
did you increase the blower speed?
 
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Old 01-13-10, 04:52 AM
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Seabee, thanks again. Thats what I needed to know. I will calculate as you described. I believe that I don't have enough return volume.
 
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Old 01-13-10, 02:44 PM
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Thanks everyone for your help. I did a calculation on cfms in and out. The result showed that I needed more return air. I added one return vent and moved the blower speed to hi. My temperature rise is now within specs. As a side note.. I did not run the furnace because of this issue. Now that it appears to be ok, I will pay for a service call to have a tech. ensure that I have everything set up correctly. Then I will warm my toes in my new house.

Thanks again..
 
 

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