grandaire furnace not so hot

New Grandaire furnace, gas high efficiency 40k btu in 1200 sft house near boston. All new insulated duct work, hooked up and seems to run right, but the air coming out of the supplies is only about 75 degrees. Any ideas why its so cool?
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wrote:

    Not enough heat ?
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On Nov 3, 9:12 pm, "Stormin Mormon"

New tstat. Heat only. Furnace has a nice blue flame. Ample return. took about 90 minutes to raise the temp from 60 to 68. I've never seen or heard of anything like this
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Most probably the furnace wasn't set up right... blower curves, static pressure, temp rise, manifold pressures and the rest. OTOH, it may be set up right if the vent air temps were taken and the house was 35 - 45 degrees or lower. I believe I would be calling the installer back to check it and make sure that its not just operating, but operating correctly.
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The house was about 60 degrees. This is the 3rd heating system this guy has done for me and I've never had any problem. He's never seen anything like this so I wondering if anyone else has.
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The house was about 60 degrees. This is the 3rd heating system this guy has done for me and I've never had any problem. He's never seen anything like this so I wondering if anyone else has.
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Like I said.... its not set up correctly. Assuming a 90+ furnace, you should have a 30 - 60F temp rise, .10wc or less static pressure, around 800 - 850cfm blower speed(depending on temp rise), and your manifold pressure will be dependant on if your on nat gas or propane. Your not getting anywhere near what your supposed to.... its not set up or adjusted correctly. If your installer can't figure this out, you need another installer.
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On 11/03/2010 09:47 PM, Cull wrote:

Is the burner cycling on and off as the blower runs continuously? If so, depending on the model, that could indicate airflow is too low. Hmmm, but then the outlet air should be hot! Doesn't make sense. 40K BTU sounds maybe a bit low, but depends on the actual heat loss of the house.
Could be something in the gas valve is set wrong, and you are not getting the correct gas flow.
Jon
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On 11/3/2010 7:47 PM, Cull wrote:

What is the name of the installing company?
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