Folks,
I've got a couple of question concerning a Goodman Furnace GPG13:

1. This furnace is rated at 138,000 BTU. My gas meter is a 2 pound system. The furnace is about 20 feet away from the meter. Currently I've got 1/2" pipe connected to it. Is this right? Or should I use 3/4" pipe? How do you size pipe for BTU ratings?

2. The fan for this furnace keeps running even after the thermostat is not calling for heat. Not a whole lot of air comes out but enough that you can feel it. The only way it shuts off is if I shut power off. What could it be?

Thanks in advance!

In my area the code calls for 3/4 black pipe. The thermostat should have a control switch for the fan. Two options are normally given; fan-on and fan auto. Fan auto runs when the furnace is calling for heat, fan on runs 24/7. 24/7 is not a bad thing. It help to keep your home temp more uniform and actually does not use more electricity than fan auto. Once a fan stops running it takes quite a bit of power to get it spinning again. The start windings in an electric motor can draw 4X as much power compared to the running load.

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Originally Posted by bamamojo

Folks,
I've got a couple of question concerning a Goodman Furnace GPG13:

1. This furnace is rated at 138,000 BTU. My gas meter is a 2 pound system. The furnace is about 20 feet away from the meter. Currently I've got 1/2" pipe connected to it. Is this right? Or should I use 3/4" pipe? How do you size pipe for BTU ratings? pressure readings help to determine pipe sizes seems ok at 1/2 inch for the btu's required

2. The fan for this furnace keeps running even after the thermostat is not calling for heat. Not a whole lot of air comes out but enough that you can feel it. The only way it shuts off is if I shut power off. What could it be? look for a fault light to see if a safty has been trippde this may explane the continous fan opperation, then as allways check filters and evaporator coils for blockage

Thanks in advance!

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Hope this has helped