A/C Not Working

[Kahunna]

All,

I have a 2011 Winnebago Sightseer with 2 roof top Coleman Mach a/c units.

Although the front unit works fine recently the rear unit has stopped working. I have checked the breakers and that is not the issue.

The blower does not run and the compressor is not running. Seems like either there is no power or the t=stat is faulty and not calling for the unit to run.

It is 85 degrees in the unit and the t-stat is set at 72.

Any suggestions would be greatly appreciated

[j-d]

Did you pull up wiring diagrams from the Winnebago site and pour over them? You might have had a wire-nut splice come loose somewhere. Winnie's diagrams will show every junction point. You can start looking for them and popping covers off to inspect the connections within.

Always the chance of a bad breaker, given the breaker is in the generator power feature, given the info you've provided so far. If your generator's like some I've seen, it has two outputs. One pretty much runs the coach as 30A and the second largely handles the second A/C...

2011 Winnebago Sightseer, correct? Please post the Model Number within that group that represents your coach. Maybe one of us will pull up a wiring diagram and look for possibilities.

[Kahunna]

Both A/C units work fine on shore power both separately and while running together. I am 99% certain that in the past both would work on generator power.

I will continue to dig deeper

[Kahunna]

So today I took the my multi meter and the trouble shooting instructions and checked the t-stat in all it choices of function ( fan only, fan and compressor, fan low and compressor, etc) and had the needed 12 volts in all settings. I then went to the control box in the return air duct in the ceiling under the a/c unit and had 12 volts there.

What I did find is there is no 115 volt power to the a/c unit even though the power control system shows power to both a/c units.

I guess I will now back track to the power control system to see if there is an issue there that is causing it to deny power to the rear a/c unit.

All breakers from the generator to the breaker panel have been reset the power control system seems like the next logical place to look.

Anyone know if there is any type of reset or fuse in the power control unit?

Any help would be greatly appreciated.

[Kahunna]

Today I checked and reset the breakers on the generator and all the breakers in the breaker panel.

The A/C unit still does not run; no fan or compressor. I even turned off the front unit to see if the rear unit would then come on. No luck.

I have a 50 amp cord but I am not plugged in. I am on Generator power.

I guess next I will get up on the roof with the multi meter and see if there is power going to the unit, if so I will then check the capacitors.

If there is no power at the unit then I will back track and check the power management system

Any additional advise????

[Clay_L]

If you have a 30 amp unit, Winnebago often has a switch that must be turned to "Generator" when on the gen. Mine is to the left of the switch panel and breakers. Maybe the switch is still in the shore power position.

It switches the rear AC to the 20 amp output on the generator.

[MrWizard]

does Your RV have a 30 amp shore cord, but a generator large enough for both A/C units,?

Check aka manually RESET BOTH circuit breakers on the generator
One breaker is tripped

It is common on RVs with 30 amp service and a genset large enough , to have the second a/C on a breaker, all by it's lonesome, on the generator

[dougrainer]

Chris Bryant wrote:
Did you check the breakers on the generator itself?

Bingo. You have 2 breakers on the genset. One is dedicated to the rear AC. Also, MOST Load Shed systems kill power to the complete AC unit, not just the compressor. The Compressor kill is on a minority of units and usually in units over 200k in cost. Doug

[Chris_Bryant]

Did you check the breakers on the generator itself?

[Kahunna]

Don't know if it is a load shedding issue. I am not plugged into shore power and am running the generator. Generator has always run both a/c units without any trouble.

Am thinking that if it were the compressor capacitor the fan would still be running. The fan is not running.

I think I need to check for fuses and get the meter out.

[Golden_HVAC]

Hi,

Usually if the load management system is shutting off the A/C unit, it normally only shuts off one compressor at a time, and leaves the fan running.

I would suggest looking at the capacitor, or perhaps the circuit board. Beyond that, you need someone with a voltmeter to check it out.

Check out this post that I made a few weeks ago. It shows a picture of the two grey capacitors, the one with the yellow and red wires is the compressor capacitor.

Golden_HVAC wrote:

Beyer wrote:
I have a 1996 camper with a Coleman A/C. I bought the Supco SPP6E. My A/C has 2 round capacitors, one small and one large. The small one has 2 wires and the large has 3 wires. Which one do I replace? Both?
Pics:

http://i1372.photobucket.com/albums/ag321/beyer25/Mobile%20Uploads/image_zpsf3f66b5c.jpg

The small capacitor with wires going to the outside fan is the wrong capacitor. THe one with wires going to the compressor is the correct one. Typically the red and another color wire go to the compressor along with a black one. Don't connect to the black one. Use the red wire and yellow wires. You want those two connections.

You do NOT take out the factory capacitor, just add the second one (they are installing a SPPE4 start booster capacitor) to the compressor circuit to help shorten the time it spends in "Locked rotor" amperage, and shorten the time it takes to get up to full speed.

Make SURE that you put a screw into the existing capacitors tie down strap, or it can short to ground if the metal from the wires shorts our to the metal of the clamp.

If your compressor is not working right, then replace the small round capacitor with the red and yellow wires on it. It might be 25 MFD or 35 MFD, replace with the same size. Shape is less important, you probably can find one for about $10 that is oval, or round one for a couple bucks more.

Fred.

[Old-Biscuit]

Can you turn that A/C Unit FAN manually ON?

Is that A/C Unit t-stat wall mounted OR part of A/C Unit?

Have you checked DC Fuses for a bad fuse.......not just looked at them but checked that none are blown?

[MEXICOWANDERER]

A load shed should shed more than just a single AC unit but of course, we're talking about the RV manufacturing industry where they need to unzip their pants to count past ten.

First order like j-d suggests is to determine if this is a forced disconnect, or if a forced disconnect is possible (equipment there or not installed) then find out what ELSE is connected to the load shed. Usually load shed should be auto recycle meaning it should reset itself automatically. Start hunting and see if anything else may not be working including receptacles (wall sockets).

[j-d]

Have there been any changes in how the coach is connected to shore power? Does this coach have any kind of load manager/shedder? Or 12VDC issues that would cut the power off to the thermostat?
Winnebago has lots of wiring diagrams on their website. Good place to start.

[dougrainer]

Kahunna wrote:
I am wondering if there is a reset somewhere on the a/c unit of maybe a fuse

The ONLY reset is the 120 breaker. I would be much richer if every time a customer has called and I ask about the breaker and they state they "checked" it, and they then come in and I walk out and find the breaker tripped. Some breakers "look" fine but you MUST turn it OFF and then on and you realize that it was tripped, it was just not sticking down like you thought it was. Doublecheck all the breakers. turn all off and then on again. Doug