Coleman A/C not cooling

[Dmitry103]

Hello friends,

Coleman Mach 15,000 BTU AC (model 48004) suddenly blows warm air. I checked wire connections at the thermostat and control board, all seem intact. There’s 12V going from thermostat to compressor. Cooling coils look a little dusty and warm to touch. I had a tech look at the unit, he said that compressor runs normal and suspects a puncture in AC line.

Does anyone have experience replacing parts on these units or it is better off replacing the entire unit? Thank you.

 

[txloser]

Someone else will chime in, but I’ve read over the years these units are typically replaced instead of fixing.

 

[Scott_Trailer_Newbe]

Does the compressor attempt to start? If YES, do you hear a humming noise when it attempts to turn over?

 

[Dmitry103]

Does the compressor attempt to start? If YES, do you hear a humming noise when it attempts to turn over?

There is a humming noise coming from the compressor when I set it to COOL AUTO.

 

[Kevin Cooper]

You didn’t say how old this AC is.
Do you have access to a clamp on ammeter? Or does your RV have an ammeter built in? The AC should be pulling 8 to 10 amps on the blue wire going to the compressor if clamp on meter. If your RV has meter around 12 amps when fan and compressor running. Low amps=low refrigerant in unit. High amps= possible dirty coils. No amps on blue or 4 amps total, compressor not running, possible control board replacement necessary.
If low amps, replace the unit.

 

[Dmitry103]

You didn’t say how old this AC is.
Do you have access to a clamp on ammeter? Or does your RV have an ammeter built in? The AC should be pulling 8 to 10 amps on the blue wire going to the compressor if clamp on meter. If your RV has meter around 12 amps when fan and compressor running. Low amps=low refrigerant in unit. High amps= possible dirty coils. No amps on blue or 4 amps total, compressor not running, possible control board replacement necessary.
If low amps, replace the unit.

The AC is about 7 years old. Yes, I have a clamp on meter. Thank you for the detailed explanation about amp draw, going to check that later today.

 

[craigav]

When you stated you hear a humming noise, was the noise, if you could tell, that the compressor is running or just humming and not running?

What I suspect which is fairly common is that you have a bad Capacitor and they are not hard to replace. You would need to turn the power off, take the top cover off the a/c, locate the capacitor, and then get the part number off of it (or you may be able to lookup the correct capacitor based on the A/C model number).

Be sure to disconnect the power first, then with a insulated screwdriver short the terminals of the capacitor as there could be residual power in it, then inspect the capacitor for leakage, bulging, swollen, etc... or just replace it. If you have a capacitor tester that would be the best test but any visual indications would also be valid.

Again, the capacitor is not hard to replace and they commonly fail and will keep the compressor from running and often create a humming sound. ~CA

Perhaps this one, but you need to check what you have already or do a parts lookup to be sure.

https://www.amazon.com/Coleman-1499...hvlocphy=&hvtargid=pla-4584001431401389&psc=1

 

[Scott_Trailer_Newbe]

There is a humming noise coming from the compressor when I set it to COOL AUTO.

Change the capicitor. Just changed the one on my neighbors 10 year old trailer and fixed. They go out quite often. Amazon has them for $14

Without a working cap the compressor can’t turn over. I used a tester (cheap on Amazon also) to confirm it was bad. More likely it’s the cap over anything else, and for $14 it’s worth a shot. My guess its a 50-5 Mf @ 370V

 

[craigav]

They are cheaper on Ebay. I suspect this is the correct one but again, check yours first and\or spend more time than I did in verifying your A/C model number and the correct capacitor. Many websites should have them as well as many electrical supply parts houses may have one locally for you if you are needing to fix your A/C asap. ~CA

Update, Scott in the above post stated 14$ on amazon which sounds about what I paid for one not too long ago. I didn't do a deep check for prices on amazon when I shared the link from Amazon.

 

[Dmitry103]

They are cheaper on Ebay. I suspect this is the correct one but again, check yours first and\or spend more time than I did in verifying your A/C model number and the correct capacitor. Many websites should have them as well as many electrical supply parts houses may have one locally for you if you are needing to fix your A/C asap. ~CA

Update, Scott in the above post stated 14$ on amazon which sounds about what I paid for one not too long ago. I didn't do a deep check for prices on amazon when I shared the link from Amazon.

Thank you for suggestion & the link. I already replaced it hoping for an easy fix, but no luck. Later today I’ll test compressor terminals, check amp draw and go from there. Anything other than the control board, I’ll probably end up replacing the entire unit. It’s 7 years old at this point.

 

[Kevin Cooper]

Thank you for suggestion & the link. I already replaced it hoping for an easy fix, but no luck. Later today I’ll test compressor terminals, check amp draw and go from there. Anything other than the control board, I’ll probably end up replacing the entire unit. It’s 7 years old at this point.

Need a video to watch about these AC units?
Go to YouTube. Search for HillbillyRV channel. Very well explained. He has a few on Coleman units.

 

[Scott_Trailer_Newbe]

They are cheaper on Ebay. I suspect this is the correct one but again, check yours first and\or spend more time than I did in verifying your A/C model number and the correct capacitor. Many websites should have them as well as many electrical supply parts houses may have one locally for you if you are needing to fix your A/C asap. ~CA

Update, Scott in the above post stated 14$ on amazon which sounds about what I paid for one not too long ago. I didn't do a deep check for prices on amazon when I shared the link from Amazon.

thats about right. Caps have gotten so cheap these days you can actually have them show up dead before you get a chance to use it. As a retired Trane guy of 28 years it was getting so bad at the end you had to stock all kinds of caps because they failed so much.

 

[Dmitry103]

You didn’t say how old this AC is.
Do you have access to a clamp on ammeter? Or does your RV have an ammeter built in? The AC should be pulling 8 to 10 amps on the blue wire going to the compressor if clamp on meter. If your RV has meter around 12 amps when fan and compressor running. Low amps=low refrigerant in unit. High amps= possible dirty coils. No amps on blue or 4 amps total, compressor not running, possible control board replacement necessary.
If low amps, replace the unit.

AC pulls around 4amps on that wire. Tech who came out confirmed that the compressor is running. I’ll start looking for a new AC unit. Thank you for the help.

Thank you to everyone who chimed in. Happy camping!

 

[pconroy]

AC pulls around 4amps on that wire. Tech who came out confirmed that the compressor is running. I’ll start looking for a new AC unit. Thank you for the help.

Thank you to everyone who chimed in. Happy camping!

That's what I had to do. Buy a replacement.
Caps didn't help.
Nothing helped.

Didn't even see evidence of a leak.

 

[Dmitry103]

Update:

Out with the old, in with the new. I replaced the unit with a power saver model this morning. Straightforward installation, took a little over an hour. The best part is that power saver model runs on household 20amp service. Thanks again for the tips and suggestions!

 

[Grumpy]

Update:

Out with the old, in with the new. I replaced the unit with a power saver model this morning. Straightforward installation, took a little over an hour. The best part is that power saver model runs on household 20amp service. Thanks again for the tips and suggestions!

Yep, as everyone has said, worse part of the job is getting the old one off and the new one on the roof...

 

[Rocksride!]

Grumpy is right, easy job except for getting the new one up there. What BTU is the power saver?

 

[Dmitry103]

Grumpy is right, easy job except for getting the new one up there. What BTU is the power saver?

15,000, same as last one. Yup, lifting the new one up on the roof was my morning workout lol

 

[parrott]

Yep, as everyone has said, worse part of the job is getting the old one off and the new one on the roof...

Old one off was easy! Just make sure no one is close by! Lol

 

[Weatherman1]

Hello friends,

Coleman Mach 15,000 BTU AC (model 48004) suddenly blows warm air. I checked wire connections at the thermostat and control board, all seem intact. There’s 12V going from thermostat to compressor. Cooling coils look a little dusty and warm to touch. I had a tech look at the unit, he said that compressor runs normal and suspects a puncture in AC line.

Does anyone have experience replacing parts on these units or it is better off replacing the entire unit? Thank you.

1) How old is it? If it is more than 8 years old replace it.
2) If 5 Y.O. or younger, and it has lost refrigerant due to a leak, you need to find the leak, install a service fitting (brazing) pressurize the system with refrigerant if there is none in it, recover any refrigerant (Need a recovery machine and should have an EPA license for handling refrigerants)
Will need an account at an HVAC supply house to turn in the refrigerant
Evacuate to 500 microns or less, weigh in a new charge of refigerant most likely 410A

Unless you have the knowledge or tools as described above, it will be cheaper to replace it.
Have fun getting rid of the old unit safely and legally.

Now if it is an electrical problem, there may be hope.
If the evaporator/condenser fan motor is running, then you need to see if the compressor is not running as indicated by humming and hot to the touch.
It may just be the run capacitor for the compressor.

Sorry for being so long winded. I did HVACR for 50 years