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Douglas, HVAC Technician
Category: HVAC
Satisfied Customers: 3089
Experience:  Manufacture Rep for Major Brand, Technical Trainer, NATE
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1994 carrier 3 ton gas pack that when the heat is on ,outside

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1994 carrier 3 ton gas pack that when the heat is on ,outside the house it smells like gas is not burning off ,, had several a/c people out and noone can figure out being doing this for years

model 48ss-0360b0301--

serial 1394g00562

there is also an area that says 4.3 lbs

You shouldnt smell gas or gas burning smell inside the home (As if you dindn't already know that).

You may insist your tech's measure the temperature rise across the heat exchanger. It really should fall within the manufacturer's specs. If it's more than 70 degrees, there is a problem with overfiring or too low of airflow. They need to verify the airflow and that the fan comes on and off at the appropriate times.

When you reference the 7pounds, this really should be 7 inches of water column. I am not sure the gas company has the capacity to supply 7 pounds or your gas valve would be blown out. 7in wc is ok for an inlet pressure provided they knock it down to 3.5 on the manifold. The gas valve has an internal regulator for this. If it cant be, either you will need a new gas valve or an inline regulator should be installed outside the unit to provide the gas valve with someting like 5" wc.


Have them verify LP orifaces were not used if this is natural gas (If its LP, the 7" is too low). There should be 2 number 32 orifaces installed for Naturual Gas. You shouldnt even smell a burning smell by the unit outside if you do, this can indicate an over firing, or problem with the venter motor not running full RPM's. This odor could be making it's way inside but that's rare.

Additionally, they need to examine the heat exchanger with a fine tooth comb (well, not a comb but visually inspect it) and if they can, they should use a combustion analyzer on the unit to determine a problem.

Lastly, if your tech is missing someting, have another one (from another company) look at it. We all miss someting once in a while and it's hard to see the forrest for the trees.

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I meant to add this one too.