GE AHM65LKM1 Icing over a bit

[czahnle]

Icing over 3/4 of the coils. No error codes. Not really used much in the past 5 years. Opening it up to clean and inspect. Ices over so much that you cannot pull the filter out from the side and ice builds up so that the bucket gets stuck trying to remove it. 

It does seem to want to go through a defrost cycle. I have unit off the floor 2 feet or so. Unit in basement windows closed. Basement temp around 65 degrees. 

any ideas? only trying to maintain around 500sqf or so.
 

[m_west5]

Is the fan running? If so, does it appear to be running at the adequate speed? In normal and high speed? What you're looking for is a "lazy" fan motor. RPM's may be listed on fan motor sticker, if you can get access to it. Unplug and let it manually defrost and have a close look at the fan and also check for a dirty coil and filter.

Also check the compressor to make sure it has turned off during defrost. If you have an amp meter, this would be the best way to check it. If not, touch the top to feel if it is off. It will be warm to hot, so be careful. Also listen closely. You'll be able to tell when it is running and not running. With it on, it will be pulling somewhere around 1.2 amps.

Did you set the control to 45-50% and let it run for 24 hours when you first ran it?

If all the above are clean and functioning properly, chances are the control/humdistat is bad. Pull it out and look for the obvious burnt components, pinched/chaffed wires, etc.

Good luck and let us know what you find.

Edited May 30, 2014 by beam current

[BryanS]

I'm assuming this is a window a/c? What is the temperature outside when this is icing up? I had a customer with a newer frigidaire window unit that would ice up in the mornings, but it's because it would be running when it was to cool outside. More than likely your coil may be dirty or a fan issue like Beam said.

[czahnle]

Beam,  the unit is clean inside,  no hair or dirt build up on the coils. they are actually very shinny!  put it back together.  unit always set to normal.  fan does run at normal speed  as it is now and speeds up to high in defrost mode.  this morning I plugged it in and turned it on i could hear the compressor turned on.   unit was set to 50%.  i did run it for 24 hours at 45% before I lowered it to 40%.  i did notice after I unplugged it yesterday the compressor was warm/hot.   actually i started writing this and in the time it took me to turn on the unit and get to this point (about 5 mins) the coils on the front closest to the filter are starting to frost.... i could hear crackling after the unit started running. i suppose that was the beginning of the frost buildup?

[czahnle]

Also,, i still have it running. I'm assuming frost buildup on the coils is normal thats why there is a defrost mode. Also, would the humidistat and controller be the little square part at the top of the grill?  on a side note I have a separate humidity/temp gauge in the basement and it is reading 60% humid as is the dehumidifier. 

[czahnle]

At the time of this post the unit is still running (roughly 50mins) Down to 57% from 60% humidity on the display. Unit still running in "normal" mode,  compressor running the whole time.  Frost buildup is at 3/4 on the front coils.  Do not see ice yet, Has not gone into defrost mode yet. What triggers defrost mode?  Timer?  The wiring diagram indicates a pipe temp connecting to the main board.  Just curious.

[czahnle]

ok,  frost now building up quite a bit.  Only about an inch of the top of the coils can been seen.  Has not started a de frost cycle yet.... humidity display says 58% humidity.  almost 2 hours passed...

[czahnle]

ok.  its now in defrost mode.  P1 on display,  all frost gone.. compressor not running just hot to the touch...no ice on coils at all...

[czahnle]

appears to be cycling normally at this time.   Gone through a few P1 defrost cycles.. Not sure what caused the big ice over? will probably happen again as i really didn't find anything wrong...

[m_west5]

Beam,  the unit is clean inside,  no hair or dirt build up on the coils. they are actually very shinny!  put it back together.  unit always set to normal.  fan does run at normal speed  as it is now and speeds up to high in defrost mode.  this morning I plugged it in and turned it on i could hear the compressor turned on.   unit was set to 50%.  i did run it for 24 hours at 45% before I lowered it to 40%.  i did notice after I unplugged it yesterday the compressor was warm/hot.   actually i started writing this and in the time it took me to turn on the unit and get to this point (about 5 mins) the coils on the front closest to the filter are starting to frost.... i could hear crackling after the unit started running. i suppose that was the beginning of the frost buildup?

 

Compressor will be warm.  This is normal.

 

Crackling sound?  I would say you are correct.

[m_west5]

Also,, i still have it running. I'm assuming frost buildup on the coils is normal thats why there is a defrost mode. Also, would the humidistat and controller be the little square part at the top of the grill?  on a side note I have a separate humidity/temp gauge in the basement and it is reading 60% humid as is the dehumidifier. 

 

"I'm assuming frost buildup on the coils is normal thats why there is a defrost mode."

 

Yes.

 

"would the humidistat and controller be the little square part at the top of the grill?"

 

Yes.  The controller is the display integrated to the top of the unit.

 

"separate humidity/temp gauge in the basement and it is reading 60% humid as is the dehumidifier"

 

Good news.  Your dehumidifier appears to be reading accurate.  This is the function of the humidistat.

[m_west5]

At the time of this post the unit is still running (roughly 50mins) Down to 57% from 60% humidity on the display. Unit still running in "normal" mode,  compressor running the whole time.  Frost buildup is at 3/4 on the front coils.  Do not see ice yet, Has not gone into defrost mode yet. What triggers defrost mode?  Timer?  The wiring diagram indicates a pipe temp connecting to the main board.  Just curious.

 

"What triggers defrost mode?  Timer?  The wiring diagram indicates a pipe temp connecting to the main board"

 

I would assume temperature.  I googled your model # for a schematic, but came up empty.  If you could post it here, we could more accurately determine this.  Easiest way would be to take a picture of it and post to a photo sharing site like Photobucket.

ok.  its now in defrost mode.  P1 on display,  all frost gone.. compressor not running just hot to the touch...no ice on coils at all...

 

Good news.   

[m_west5]

appears to be cycling normally at this time.   Gone through a few P1 defrost cycles.. Not sure what caused the big ice over? will probably happen again as i really didn't find anything wrong...

 

"Not sure what caused the big ice over"

 

Did you clean the filter and coil?  This would definitely cause this problem, as brother Bryan and I stated.  Make sure the fan blade is clean also.  I'm sure you are aware this is part of the routine maintenance.

 

"will probably happen again as i really didn't find anything wrong..."

 

Let it run and see what happens.  Come on back and please try to post the schematic.

[czahnle]

Hey Beam,  i really didnt do much except let the powered th unit off and let it manually defrost. the coils were clean and shinny silver!  the filter didnt appear to be cloged.  I did brush off the fan wheel but it looked just dusty.  i will get a pic of the wiring diagram and upload..  

[czahnle]

ok,  try this link for the pic of the diagram.  hopefully you can read it.  

http://s30.photobucket.com/user/czr12x/media/WP_000805_zpsd4f681ad.jpg.html

[m_west5]

Thanks for posting the pic. Hard to see, but from what I could see is that it is temperature.

I would suggest that you also reseat the main pcb connectors. They probably have tiny release tabs on them. Use a very small flat blade screwdriver to help release the tabs as you pull on the connector. Be carefull, they're somewhat fragile. Also inspect for corrosion and "flattened" pins and sockets. Pinched and chaffed wires too.

Has it been running ok since a few days ago?

[czahnle]

This would be the connector on the main board or the controller board as well?  Its been running set at 55%.  Last night it stopped running and the display was reading 58% or so.  I drained the bucket of water (wasn't full) and dropped the setting to 50% and it started running.  One thing I noticed is that once I returned the bucket and the code cleared for that the humidistat was reporting like 43% or something.  While my separate humidity/temp sensor across the room was reporting 58%.  it began running shortly after dropping the setting to 50%.  

 

This morning I checked on it and it has a little bit of water in the tank and ice on the side of the coils, heavy frost on the front of them. The filter would not come out as its stuck in the frost / ice.  Display is reading 56% at the moment.  The other sensor in the basement is reading 62%.  

 

I then moved the other sensor to the same location in the basement where the dehumidifier is ( about 5 feet away, same height) and that sensor is dropping and getting closer to the reading currently on the dehumidifier. temp in the room states 68F.  i am expecting a defrost cycle to happen soon.  hopefully to clear the coils.  will report back. 

[czahnle]

haven't reseated anything yet.  Hasn't ran since my last post.  Power cycled. after 10 mins display states 31% humidity and my other gauge states 57%.  something isn't reading right... lol

[czahnle]

power off for 10mins or so.  powered up.  dropped setting to 45% and the unit turned on right away,  has been running for a few hours without a defrost cycle kicking in...  unit says 53% external sensor says 52%, 

[czahnle]

well the unit appears to be working... i just never see it go through a defrost (p1) cycle.  i almost wonder if when it reaches the desired setting 55% it stops running and that is how water ends up in the bucket... the reason i say this is because the frost/ice built up get to the point that condensation builds up on the surface of the unit and then runs down the side onto the floor.    if i remember correctly in the past we would regularly see p1 cycles all the time.  just a thought. 

[czahnle]

well the unit appears to be working... i just never see it go through a defrost (p1) cycle.  i almost wonder if when it reaches the desired setting 55% it stops running and that is how water ends up in the bucket... the reason i say this is because the frost/ice built up get to the point that condensation builds up on the surface of the unit and then runs down the side onto the floor.    if i remember correctly in the past we would regularly see p1 cycles all the time.  just a thought. 

also..  if the unit is no longer performing defrost (p1) would this mean the board is faulty? can it be purchased?  i would be willing to do that if it wasn't too horribly expensive.  

[m_west5]

Few things to try:

Get an amp meter and read the compressor (run winding, look at the diagram) during normal operation. Somewhere around .8 - 1.2 amps. This would tell you if the compressor is operating as it should.

Reseat all connectors on the board and closely inspect for heat_stressed components, corrosion, loose connections, broken pins and contacts, cold solder joints, etc. Get a very bright flashlight and magnifying glass and take your time.

This rules out most everything, which does point to a flakey board.

I'll check on the board cost and availability. Stand by.....

[m_west5]

So I went 5 pages deep into a google search for your model number and it appears that the main pcb and sensor are NLA. Also checked all my parts sites, ebay, and amazon.

The only thing I could recommend is to look for a part number printed ( or a sticker) directly on the board itself and google it. I would not rule out the sensor either. Chefk that for a part number also.

Also, do you see any oil residue anywhere on the sealed system? This would indicate a refrigerant leak, which would cost to much to repair.

Please let us know what you find after checking all the above. Especially compressor amp draw after its been running for at least 15 to 30 minutes.