RV roof A/C trouble shooting:

[Synchro Joe]

https://coleman-mach.com/rv-owners/

[Tishabet]

Originally Posted by speeder

Never knew there was an Airstream RV like this, that thing is badass!

[1990C4S]

I'm gonna guess that if the fan does not run when it's set to 'FAN ONLY', then you have a failed fan, or more likely, no power to the unit.

Does the fan come on?

Next I would check voltage at the compressor. Zero volts? Probably low gas pressure. Find the pressure switch.

[speeder]

I need to get up on the roof but it's just too damn hot here...over 100 degrees. I honestly don't know how people in the hot parts of the country survive without an ocean to jump into...I'm hanging at the beach until next week when the weather changes.

Yesterday, first two @ Will Rogers in Santa Monica and last one Malibu:

[speeder]

Originally Posted by Synchro Joe

https://coleman-mach.com/rv-owners/

Originally Posted by 1990C4S

I'm gonna guess that if the fan does not run when it's set to 'FAN ONLY', then you have a failed fan, or more likely, no power to the unit.

Does the fan come on?

Next I would check voltage at the compressor. Zero volts? Probably low gas pressure. Find the pressure switch.

Thank you guys very much for the help! I'm going to climb up on it soon.

[speeder]

I went over and poked around a little on it and the front unit still works like it did when I bought it but the rear does not. I checked the main breakers in the coach and found the switch for shore vs. generator power, it was in the wrong position and when I flipped it, the unit turned on. Blows cold but I still want to service it if possible. I took the big cover off of it and it needs a good cleaning at the least. Lots of pine needles and dirt under the cover.

So what am I looking for on the one that does not turn on? What does the start up capacitor or whatever it's called look like and where might I find it, if anyone knows? I took some photos:




Also, the generator, which has always started right up and sounded good, seemed to be straining powering just one A/C unit and started smoking visibly...I shut it down when I noticed. It's a standard Onan unit found in RVs but it runs on LPG instead of gasoline because my RV is a diesel. On the gas Airstream RVs, (much more common), the generator ran on gas. I can change the oil and check the air filter but I really don't know what else to check or service on it(?)

Granted, it was over 100 deg. today but if the generator can't handle that, (powering A/C units on a hot day), what good is it? I cannot see how it cools itself...is there a fan in this thing somewhere? All knowledge apreciated!

[fintstone]

Just follow the wires from the compressor back into that box on the left. You should be able to remove a couple of screws to get into the access panel/cover. The capacitor is usually shiny and a little smaller than the size of your fist (with wires going into it). Probably have one for the fan and one for the compressor.

[fintstone]

This video might help. It shows a fellow replacing the fan capacitor. Looks like one for the compressor is right next to it.

[fintstone]

Might see it better on this parts breakdown:

https://youngfartsrvparts.com/pages/coleman-mach-1-el-air-conditioner-product-id-6744a901-parts-list?srsltid=AfmBOooay6zMGoLZGj8UgYlratbr8GRMd90bv wJ-wQ69x537EiFAZZ6f&shpxid=75490701-e96a-4003-9342-bd31a18bc898

[rfuerst911sc]

Originally Posted by speeder

I went over and poked around a little on it and the front unit still works like it did when I bought it but the rear does not. I checked the main breakers in the coach and found the switch for shore vs. generator power, it was in the wrong position and when I flipped it, the unit turned on. Blows cold but I still want to service it if possible. I took the big cover off of it and it needs a good cleaning at the least. Lots of pine needles and dirt under the cover.

So what am I looking for on the one that does not turn on? What does the start up capacitor or whatever it's called look like and where might I find it, if anyone knows? I took some photos:




Also, the generator, which has always started right up and sounded good, seemed to be straining powering just one A/C unit and started smoking visibly...I shut it down when I noticed. It's a standard Onan unit found in RVs but it runs on LPG instead of gasoline because my RV is a diesel. On the gas Airstream RVs, (much more common), the generator ran on gas. I can change the oil and check the air filter but I really don't know what else to check or service on it(?)

Granted, it was over 100 deg. today but if the generator can't handle that, (powering A/C units on a hot day), what good is it? I cannot see how it cools itself...is there a fan in this thing somewhere? All knowledge apreciated!

I believe the cooling fan is inside that square housing on the left in your pic . It pulls air across the engine/head/oil filter . So air flow is left to right when looking at the unit .

Could you tell where the smoke was coming from ? What color smoke ? When these sit it could be as simple as bugs/bees built a nest to mice built a nest to dirt/leaves build up or mechanical like stuck piston rings .

I think you will need to pull some cover plates or whatever you can to do a good visual inspection . Also because of the age every wire needs to be looked at for cracked insulation and rodent damage . Cool rig good luck with getting her going .

[javadog]

There are probably 3 capacitors. Most likely they will be located behind a removable cover (the galvanized sheet metal on the left side of the compressor in your picture.). Turn off power to the unit, take notes of which wires go where on the three capacitors, remove the wires, discharge the capacitors, remove them and take them to a new supply house to have them tested.

There is probably a thermal cut out under the little cover on top of the compressor, test it to make sure it’s OK, first.

If you don’t know how to do any of that, YouTube is your friend.

[javadog]

Of course, my advice would be to first find the circuit board, which will usually be located by removing the grill inside the RV, and looking up into the area next to the evaporator. I would make sure you have power coming to the unit, that I would test, the thermostat wiring to see if it is calling for cooling or the fan to blow, when you try to run it.

If that all checks out, then get up on top and to see if the fan turns freely and has no free play.

If that’s fine, then check out the thermal cut out and the capacitors.

[greglepore]

You did check the oil in the genset prior to starting it, right? Who knows what happens when stuff sits for a long while.

[cstreit]

Many AC have a largish relay to manage the startup current. I'd look for one of those too. Wouldn't be surprised that one would stick after sitting so long. I'd start with that and move on to the start capacitor.

[javadog]

The other symptom is the fan won’t run…

Start at the beginning…

[javadog]

Hey Denis, buy me a plane ticket to LA, a hotel room in Santa Monica and all the sushi I can eat and I’ll come out and fix this for you.

[1990C4S]

Originally Posted by greglepore

You did check the oil in the genset prior to starting it, right? Who knows what happens when stuff sits for a long while.

Air cooled generator + mice = blocked air flow. That's my first guess. The inside probably looks like the AC units.

The governor linkage is next, it should run at a fixed rpm (3,600?) to make 60 Hz power.

A meter that can measure voltage and frequency might help you down the road.

[speeder]

Thanks a million! I did not check the oil in the generator yesterday but I've checked it in the past and it looked clean and proper level. The entire unit is going to get a proper servicing now before I start it again. It's always fired right up and sounded great but I haven't been loading it up. I will remove all cladding and look for debris.

Fint, thanks for the videos and Java, I'll keep your offer open!

[911boost]

I have had a gas powered Onan and my current rig has a diesel powered one. While not your issue, my gas one hated any gas with ethanol. In the rare occasion is used gas with ethanol I always drained the bowl before parking it.

Good points on just taking things apart and looking at the airflow. For mine they did not recommend running them without the covers on as it affected the airflow. They are pretty sturdy and while AC's pull a lot, if it was struggling getting it serviced is a good idea after you check for blockages.

[Gogar]

Yeah start with the basics and get out a meter and see if you are getting power there at all.