AIr Conditioner not working 2013 Via 25T

[thataway4]

2013.Via 25 t

Intermittent AC compressor running. Fan works when “ON”; only if compressor is running if on “AUTO”.

Thermostat/Controller: “RVComfort.BP”: Coleman Mack(?)

This was intermittent, then worked OK before we left. Worked first day on our trip. Next day on&off. Today not working at all. Tried turning “off”. Pulled the fuse in thermostat— no joy. Disconnected power—nope.

No mobile techs or RV service within reasonable distance.

Any suggestions?

[Lv2Roam2]

A/Cs are not one of my strong skills - on my coach this is what I'd try:
- Pull the shroud and look for good wire connections throughout
- With the thermostat on do a '12V reset'
- Consider the start and run capacitors
- See if the fan motor shaft / blades will turn by hand (with all power disconnected)
- Post this same question on IRV2 for a wider audience

Let us know what results - we all learn! Thanks ...

[thataway4]

Thank you. The compressor runs normally, when running. Also will run in reverse cycle (electric heat) when running.

[thataway4]

I have a feeling it is in controller. Unfortunately I did not bring my collapsible ladder,plus I am 87 y.o. & wife (properly banned my getting on the roof. We have a younger & more capable couple traveling with us; he is in late 70’s…not sure. I want him. On the roof…hopefully is something with the controller, but I guess that the compressor would be attempting to start if bad start capacitor?? Thanks

[Morich]

One small point that we CAN check without getting on the roof is the thermostat and wiring at that point.
I believe this is the correct one for your RV but if the colors look different, do a search for your specific thermostat before trusting!
Understanding that the thermostat is just a switch for the various functions but done by itself when the temp changes is one way to look at it.

When it decides to turn some part on, it connects two wires together much like we do at a normal wall switch. So if WE connect those two wires together we should expect to get the right part to work!


This picture and chart show where we can expect to find those wires. Getting the cover snapped off is what may be the harder parts, so do some looking/searching for the place where it is snapped on and get it off the wall as a big thing??? They hide those spots and change, so no help there.

Once off the wall, it may be as simple as some wire connection is not solid, so pull them up out of where hidden in the wall and make sure all the wire nuts are twisted on solid.
When things are intermit. it takes a longer slower process to make sure we are not walking past the true problem, so much slow and test slow.
Point is that we may get the wires corrected but not make sure it is working or failing and move on where we can cause other problems! Gets double hard that way.

First decide WHAT function is not working. Is it the fan, the compressor or WHAT? Am I reading correct that the compressor is not always working?
Define the problem first to cut down the ares to look and test.

Once deciding what is the problem, move to test that set of wires. My feeling is that the capacacitors are not likely to be intermitant as they are needed to first make the compressor start and a second set to help it run. They tend to fail or get weak and stay weak or failed! Rarely do they heal.
Most of the moving parts are bad and stay bad or good and stay good but the electrical connections are known for getting funky and doing weird things.

Look at the color chart as being the wires coming out of the thermostat, NOT the wall colors as they are not always the same.
Leave the 12 volt negative (ground connection) connected at all times to test, then connect the item you want to run to the wire in the wall that is connected to the red wire from the thermostat!
That's where this picture is leaving me a bit in doubt as it is not clear, so look carefully before trying them. Are there two red wires in the wall? One connected to yellow from therm. and one connected to red from therm?
Whatever color coming from the wall to the red wire of the thermostat is your power wire and connecting it to the wall wire of the comolr that goes to the compressor, should make the compressor run! Or low, high fan, etc. !


I hope that is not confusing you but you need to id the wires looking at the chart and the wires from the thermostat but it may change colors when you want to test a part. Connecting the two wires of whatever colors are correct that come out of the wall is what you need.

I "think" I see red /white from the wall as 12 volt positive and connecting it to red from the wall sends power out to relay that starts the compressor!

Note that this will test the thermostat and the wiring on this end but then it may be a loose connect, etc at the roof end, so not a complete test, just ruling out one possible cause?

[thataway4]

Thank you Morich.

This is precisely the type of information I need . No problem with circuits (long term HAM operator, design
Of circuits etc. also built several boat enteric freezer/refrigerator systems!)

Already had the cover off thermostat.

Problem is compressor will not run. Internal fan ducted unit runs when “on”, but not in “auto” mode.

[Morich]

Okay, better idea of where to go with ideas. No good shooting out ideas if there are totally missed!
But some questions may help?

When it should start the compressor, do you hear any loud hum like it is getting the signal but just won't turn over? That might lead to things like the start capacitor up on top or maybe just simple wiring open, bad relay, etc.

But if no hum or signs of trying, then you might want to look at the wire labeled compressor coming out of the thermostat to see if the signal is getting sent that direction and might be as simple as a bad thermostat?

From there it may be up top and my age says we should not want to go there!

[Morich]

As an added thought, it might be worthwhile to check that the breaker has not got hot and tripped while trying to start a slo compressor or while testing? If we turn AC on and off, then on again too soon, it can be working to start against too high pressure and wierd can happen, so don't walk past that if it is just not trying at all now?

Your electrical for 110 Ac is here:
https://www.winnebago.com/Files/File...ire_182126.pdf

Or click this snip to get a better view if not sure which breaker, etc.



I can work on things quite a while when they won't run only to remember I unplugged it to test!

[thataway4]

None of issues that Morich asked about were were present.. Was Normal. Startup when the AC was working.

I pulled the thermostat Board off the wall. 1 1/2”. Hole where I could see two 3 wire harness connectors. The hole was too small to get the connectors out, without enlarging the hose. I pushed & pulled to be sure connectors were making good connections. Of course all of Winnebago wires were yellow. I could not see if each wire had printing. The 42’ Monaco pusher I owned for10 years did have every critical wire printed with a function or code.

I put the 12 volt fuse in place, turned the AC “on”. We now have air conditioning again. So my suspicion that it was a bad connection somewhere in the controller appears to be correct.

The photo which Morich posted had wire nuts. Not sure where this photo came from. However wire nuts have no place in airplanes, boats, critical or medical gear….and I add any recreational vehicle!!!

When we get home I will enlarge the hole to the connectors and double check all of the wires to the thermostat/controller.

Thanks for the help!

[Morich]

the picture was one I snipped from some info posted on the Coleman mach so l;ikely the way they were installed at the time. But whether wire nuts or plugs are better, there might be defects in both systems as shown by the point you make of seeming to solve the problem by playing with the plugs you have!
Wire nuts and plugs both have their own special little quirks that lead to faults. Which we feel is better is often decided not by facts but by which one has just failed us!

For a far more reliable connection I would suggest cutting those plugs off as they seem to be giving trouble and do a really good job by soldering the connections as that is one of the more reliable ways to prevent future trouble.

But that is not something I will ever expect to see in any mass production RV! Way too much labor involved to do that sort of thing.

[thataway4]

Time to give follow up and resolution. On the trip, it appeared that it was not really the Jiggling of the wires, but something inside of the thermostat box. I pulled the cover of the thermostat, and started tapping on the mini relays. The original thermostat number is
RVP:8530-338. TIANBO relay TR5V M-S-Z is the number of the two mini 12 volt relays. The one nearest to the thermostat up/down switches is the cool, the other is the reverse cycle heat for this air conditioner. Tapping on the first mini relay turned the air conditioner on, and it ran until the specified temp was reached. To start again, one had to tap the relay
"just right so". So we survived doing that for 5 days. We were out in the boat most of the day, so it was mostly in the evenings. I checked the plugs and all were good continuity wise.

Arriving home I began the quest to find a replacement Thermostat RVP part number 8530-338. Basically they don't exist. Winnie parts said not their problem. Coleman basically, said we don't make those or support those anymore. There are several web sites, which listed some replacements in stock, but I was suspicious of the sites. My son's business is very high dollar money transfer security. I asked him, and he agreed to not open these sites--I later found out that they were scams, and just trying to get the credit card numbers--no items. There is an item which is RVP 8830-3862. It is identical to the one present, except it does not have the reverse cycle heat switch. Even the wiring is identical. I traced the circuit out to be sure. Today, I used marine grade butt connectors with adhesive heat shrink tubing, and installed the new thermostat, using the original plugs. The AC immediately came on and is functioning normally. The reverse cycle AC "heat Pump" does not work, but the gas heat does. This is fine for us, We rarely use the reverse cycle heat pump, and usually use small cube heaters (800 watts/1200 watts) for heating, or the gas furnace if the temp is really cold.

The replacement thermostat came with complete instructions and a nice illustration of what each wire does. But it did not include the defective unit, which turns out to be identical, except it has a white wire with a black strip--which controls the reverse cycle AC heat pump function of the RV roof air.

So the issue was failure of a mini 12 volt relay on the circuit board. I can get this relay ($6), and may try and replace it when I have nothing else to do. This means pulling the circuit board out of its case, and I think I see a way to do this with no damage. As many of you know it can be tricky re-soldering these printed circuit mini boards. So I don't want my heat or air depending on it. I will get another set of plugs if I have successfully repaired the board by replacing this relay. Then I will check the board--and if it works OK, keep it as a back up.

One comment about the butt connectors vs soldering connections. As a long term electronics builder (My father was a Cal Tech graduate electrical engineer and having obtained his first HAM License in 1923), I had a very good mentor. The garage in the house I grew up in was filled with giant radio tubes and various circuits. I learned enough about circuit design before I was out of high school to design and build my own stereo amps, simulcast AM/FM stereo receiver and reel to reel tape recorder pre amps, amps etc when I was in college . I also started soldering over 70 years ago and have given tutorials on soldering (mostly VHF radio PL 259 plugs) to boaters. So I would agree it seems like a good soldered joint would seem logical. However the point made in both aircraft/aerospace and boating (ABYC standards), if soldered it must have substantial support of the wire, because of the possible work hardening of the soldered area of the thin stranded, tinned copper wires due to vibration. Butt connectors are the choice for boats. (Again per American Boat and Yacht Council.) I prefer butt connectors with adhesive lined shrink tubing so that this gives a physical support to the wire for about 1/4"-3/8" on each side of the metal crimped butt joint connector. I use high end ratchet crimpers to get consistent crimps.

Thanks again to all who come to my rescue and directed my diagnostic efforts!!