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Old 05-21-2008, 09:50 AM   #1
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another A/C question


I have a slightly used Trane A/C - Gas-Heat air handler in my attic.

For HEAT, the unit appeared to me to operate ok, but it didn't actually
generate any heat. I called a guy out and for $45, he flipped a switch
on the inside of the air handler that actually turned on the heater part
of the unit. Without the switch, the gas could come on, the pilot light
would kick on, but the unit would shut down after a few seconds and
it would cycle through the process again. Aparently, this 3rd air unit
in the 4 year old house was not used for Heat much.

Now.. 2 months later, I want to use the air unit for A/C and I seem to
have a similar situation... the a/c comes on but it just doesn't blow
cold air. My OLD unit, in my OLD house was a piece of cake to work on.
It was a vertical stack in my hall closet that had air coming in from the
bottom, a replaceable air filter, a/c/ coils, a squirell cage fan, an electic
heating element and then it sent air out to my main vents.

I can't figure out this new TRANE unit at all. It is in the attic and is
horizontally mounted / suspended. I can't figure out which end in the
'in' and which end is the 'out' and have no idea where the 'blower' part
is. I see the 'gas/heater' part and don't want to blow anything up...
How do I check the blower/coils to make sure that they are clean?
Is there a magic A/C switch that turns on the A/C part like there is
with the Heat?

Thanks - jack

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Old 05-22-2008, 08:50 PM   #2
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another A/C question


the unit in the attic is basically a vertical unit hung horizontally.the area where you pull the filter out is the air into the unit and the fan is next then the heater and finally the cooling coil.your air out goes out and branches out to the rooms the return end should be a single duct back up to the unit...your filter might be a grill in the upper hall or attic ceiling not in the unit. investigate it a do a good inspection on that sqirrel cage sounds like might be rounded off with dirt if your tripping heat a feel minimal on cool or heat.NOTE heat is low speed fan and cooling is high speed

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Old 05-23-2008, 07:16 AM   #3
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another A/C question


Quote:
Originally Posted by biggles View Post
the unit in the attic is basically a vertical unit hung horizontally.the area where you pull the filter out is the air into the unit and the fan is next then the heater and finally the cooling coil.your air out goes out and branches out to the rooms the return end should be a single duct back up to the unit...your filter might be a grill in the upper hall or attic ceiling not in the unit. investigate it a do a good inspection on that sqirrel cage sounds like might be rounded off with dirt if your tripping heat a feel minimal on cool or heat.NOTE heat is low speed fan and cooling is high speed

I located the 'fan'. When I turn on the A/C unit, the fan comes on, but its' really, really
quiet and you can barely tell that it's on. I 've opened up the access panel and
everything is clean/shiny. The fan / control board is mounted so that I can't really
see inside of the fan. I can press the access/door/button switch and have the
unit engage and I know that it comes on. but it doesn't seem to move a lot of air.
This is a small, 1.5 ton unit that is supposed to provide cooling for my Master Bed
Room / Mater bath. The outside air unit comes on when the A/C comes on. It
does provide 'some' cooling but just not a lot. The Room can be 80, I turn on the
A/C and 60 minutes later, the 14x14 room is 78. My main house unit can cool
2000 sqft from 80 to 78 in about 15 minutes.

I've replaced the air filter and it's good to go.

I hate to make a $60 service call if it's something simple...

jack
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Old 05-23-2008, 11:53 AM   #4
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another A/C question


If you just think air flow is your problem, check to ensure that the black wire from the supply fan motor is hooked up to the cool (or high speed)terminal on your furnace board. take the other wire that was on the cooling terminal and put it on the park or unused terminal. Verify that there is no ice on your ac coil or that there is nothing else in the system that is causing you to lose airflow. If airflow is wired for high speed, then check your a/c unit to ensure it is cooling properly. The large copper line to the unit should be quite cold tot he touch, but not icing up. If this is not the case, then you should get someone in to look at the ac. hope this helps.
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Old 05-23-2008, 06:49 PM   #5
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another A/C question


On your thermostat, switching the fan mode from auto to on, should switch the fan to high speed. If there is no increase in airflow, you should probably call someone.

1.5 ton A.C.= 600cfm, not a whole lot of air.

The fan will continue to run until you switch it back to auto.
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