Author Topic: ge PTAC  (Read 4076 times)

Offline alex

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ge PTAC
« on: August 27, 2009, 12:46:25 PM »
Have a GE PTAC unit that is causing problems.The model no.is AZ38H15DADM1 serial no FH320668,it is about 8-10 years old.When you turn the unit off there is something still humming like a motor trying to start.I took off the front and pulled it out of it's case and found that the compressor is what is humming and viberating like it wants to start or run even though the switches are set to off.I checked the compressor terminals to ground and found all open or not grounded.Ohmimg the terminals I got 1.6 from S to C  2.4 from R to C  and from R to S 4.1 I then checked the capacitor for grounding there was  no visiable grounding.I took the capacitor out and let it  hang free, still hooked up, same thing compressor hummimg.I then changed the capacitor to a new one,same thing,compressor humming.I unhooked the connectors to the control board,one with the switches on it,and the compressor humming stopped.Does this mean that I need a new board?Other than not being able to cut this thing off,it works and cools realy good.Can you guys help me to troubleshoot this unit?

Offline rmuntz

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Re: ge PTAC
« Reply #1 on: August 28, 2009, 11:26:33 AM »
I'm not familiar with these units but just some general comments.
The S-C ohm reading should be higher than the R-C reading and the S-C plus the R-C should roughly equal the R-S reading. You may have wrote the terminal letters down wrong. If the readings are as above the windings are ok.
Do all the compressor wires come from the circuit board? Do the compressor terminals have any voltage on them when the unit is turned off? If so its quite possible the circuit board is defective.

Offline alex

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Re: ge PTAC
« Reply #2 on: August 28, 2009, 01:08:51 PM »
Thank you,rmuntz for your reply.I was thinking that the start windings should have been the highest,but they aren't,I checked this three times and still got the same readings.What does this mean if anything?One of the wires going to the compressor come off the drive board unit,witch works inconjunction with the main board unit (one with control knobs) This wire goes to the overload protector on the compressor.The other two wires go thru the capacitor,one to S and one to R. The wire from the board seems to have voltage.It is L1 from the board to the OLP. The other two wires are L2 thru the compressor.L2 is a straight hot from universal power connector.What do you think?

Offline alex

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Re: ge PTAC
« Reply #3 on: August 30, 2009, 01:59:44 PM »
Noone has any thoughts on what might be wrong here?After looking at the boards and checking I am leaning toward the fact that a relay is stuck on the power board.These boards are over a 100 dollars so I wish one of you HVAC guys would respond with your thoughts.Thank all of you for your  time.