Expert A/C help needed

[apgarrett]

Need a sanity check.

Background:

10 day trip to South Dakota (amazing but hot). On the last day, front ac (Mach 15 on 2020 precept) dies. I was running on the generator on the way home. Breaker trips on generator. Reset. Fan runs. No Cold air.

Check everything with a volt meter. Fan and start Capacitors good. Thermostat inputs to control board. Good. Control board out. Good. Compressor and relay good. Assume I lost coolant. Call dealer. 16 weeks. Buy new ac unit because i want to camp this summer. Install new unit through acts of courage and strength. New unit doesn’t have new control boards… really. (old unit had the main control and the temperature control board). Put old control board on new unit. The temperature control board doesn’t seem to be needed on the new unit. Wired directly (like back ac into the compressor). No cold air !!

Double check everything. Swap back ac control board to front. Nothing. Put front board to the back unit. Back ac runs like a champ with the control board. So it’s good.

Swap both freeze thermocouples. All good. Both power up the back.

Check the breakers. All good. Double check the generator and try to run on it without shore power. Same results. Fan yes. Cold air not.

The compressor gets hot. But the coolant line doesn’t get cold.

Did I get a lemon or am I missing something. I’ve checked every circuit I can think of.

[RPR]

Do have a clamp on amp meter? Room to put it on the ac power line at the compressor to see if any current is flowing right when you turn unit on.

[apgarrett]

I can put my fluke meter on and hold it. No issues there.

Where would I put it it on the compressor? There are the three poles.

Tell me what you are thinking.

[RPR]

You may have voltage but no current flow. Seeing if and how much current(amps) the compressor is drawing.

[apgarrett]

Originally Posted by RPR

You may have voltage but no current flow. Seeing if and how much current(amps) the compressor is drawing.

Ok. I’ll check it tomorrow. I’m assuming from the capacitor to the compressor.

[apgarrett]

Zero amps out of the start capacitor to compressor.

Not sure why.

[apgarrett]

Never mind. Bad fuse in meter. I did have current. I just need to step away from this. I’m making bone head mistakes.

So frustrating. I feel like I missing something simple, but I’m starting to think I got a lemon.

[Gary207]

There will not be an amp reading on the start compressor wire try another wire. On the compressor there will be two copper tubes one bigger than the other the smaller on will be HOT to the touch and the other cold under normal conditions indicating the compressor is pumping refrigerant. The amp reading will tell you if the motor is running or take a screw driver hold the end on the compressor body the other end of the driver hold to your ear and you will hear the motor running. If your compressor running and the small tube on the compressor is not hot chance’s are it is short or out of refrigerant.

[apgarrett]

Compressor is running. Confirmed by amps, humming, and the screw driver test.

I got a lemon. Thanks for the tips.

[pconroy]

Originally Posted by apgarrett

Compressor is running. Confirmed by amps, humming, and the screw driver test.

I got a lemon. Thanks for the tips.

My Mach 15 leaked out all of it's refrigerant after a couple of years. I don't think the quality is in those units, that I'd expect.

[Marcm157]

Just want to know how you confirmed the caps are good? Did you meter and read Mf's? I've seen many instances where someone will assume a good capacitor but not actually verify micro farrads.

[apgarrett]

I checked them with my meter.

[GerryB54]

2018 Jayco Precept 35s - my main AC unit is doing the same thing, trying to troubleshoot and have an onsite service appointment set for 8/10...hope you find out what's happening.

[RPR]

Search the web and info on why possibility the capacitor could be the problem.

[pconroy]

Originally Posted by GerryB54

2018 Jayco Precept 35s - my main AC unit is doing the same thing, trying to troubleshoot and have an onsite service appointment set for 8/10...hope you find out what's happening.

I hope your outcome was better than mine. I replaced the caps, and everything tested fine. In the end, the only thing left was "no refrigerant"

[Yooper906]

Originally Posted by pconroy

I hope your outcome was better than mine. I replaced the caps, and everything tested fine. In the end, the only thing left was "no refrigerant"

I have no idea why the AC manufacturers don't put ports on these units. The cost seems like it would be minimal.

[apgarrett]

Originally Posted by Yooper906

I have no idea why the AC manufacturers don't put ports on these units. The cost seems like it would be minimal.

Money I suppose. Really frustrating how much time I’ve spent on this. I’ve asked for a refund and ordered an Atwood air commander. I’m sure it will have its issues too, but I have no faith in the Coleman units right now.

[Gary207]

They do make clamp on access valves. Sup o 3in one refrigerant access valves is one brand. They also make an additive to stop a refrigerant leak you add to the system.

[JohnH]

Had the same with our 2021 Precept. Ended up changing out the front AC. Here are few hints to look at, without getting on the roof. You can check the compressor current from inside at the control box. Pull back the green wire mesh and put the clamp meter on the purple wire. A good operating system will indicate between 12 to 14 Amps. A unit that has lost the charge will show about 4 to 4.25 amps.


I did find the leak and to my surprise the case of the compressor had a micro hole in it. Pure and simple bad material selection by Tecumseh.



I was able to effect a repair, install service ports, evacuate and recharge to specs.



Down side is I did replace the unit, and now have a spare.



Did not replace with a Coleman. Went with a Haughton roof unit. Doesn't use a remote thermostat has all the necessary parts built in and uses a remote control. Quieter and a lot more efficient.



At its best the Coleman would only get a delta temp difference of 19 to 21 Degrees, Where the Hauhton is averaging 28 to 30. Supposedly has a built in soft-start, But I cant confirm this. Quite pleased and I'll also mention about 400 bucks less expensive.


As always IMHO

[Bsenecal]

Our 2018 Jayco Precept 29v had the same issue with our front A/C. Started not working right at the 2 year mark, I had probably used it less than 40 times. Due to my lack of trust at the dealership we purchased it at who said the whole unit needed to be replaced and that neither they or Jayco would honor the 2 year warranty as I was 1 month beyond the 2 years I found a local RV repairman who diagnosed and replaced the A/C? heat pump and $2400 later I have a working unit.
Brian