AC Help!

BayouBoys · 03-23-2015, 03:34 PM

Just returned from a quick weekend trip after 6 months of storage. The AC was giving me problems. I have a Dometic single zone LCD thermostat. It was set at 74 and auto. The AC would run for about 2-3 minutes the shutoff for 2-3 minutes and so on.

My first thought is the thermostat, any ideas?

**JRTJH** · 03-23-2015, 04:24 PM

Is only the fan running/shutting off? or is the compressor also running/shutting off?

When the thermostat fan setting is HI or LOW, the fan should run continuously at that speed. Only the compressor will cycle on and off as cooling is required. When the thermostat fan setting is in AUTO, the designed function of the A/C is for the compressor to start, then after a slight delay, the fan starts on high. When the temperature drops to (I think) 4 degrees of the thermostat setting, the fan will stop, and then resume on low. If the temperature continues to drop, when it reaches the thermostat setting, the entire system will shut off. Then when the thermostat calls for cooling again, the cycle repeats. The compressor always starts first followed by the fan.

During the A/C fan "speed changes" the fan will shut off for about 10 seconds, then resume. The compressor continues to run during this speed change.

The above is normal A/C operation.

If, on the other hand, your A/C is cutting off completely (fan and compressor) and then starting up again 2 or 3 minutes later, your heat anticipation cycle in the thermostat is probably not set properly (faulty thermostat) or there is a voltage drop below about 106VAC and the A/C is overheating due to low voltage and cycling to prevent damage.

Check your input voltage to be sure that it is between 110VAC and 125VAC when the A/C is running. If you check it with the A/C turned off, you won't measure a "load voltage drop" and will "miss the problem". The way to check for voltage is to use a multimeter and measure the voltage at one of the outlet plugs in the camper when the A/C is operating. If you check before turning the A/C on, then compare the voltage while the A/C is running, you can determine the total voltage drop.

Good Luck

tom37 · 03-23-2015, 04:32 PM

If the weather is hot and humid, I set the fan to run on low all the time and the compressor cycles on and off when it needs to.

raineman · 03-23-2015, 08:18 PM

A clogged filter will do that too

2014Fuzion300 · 03-24-2015, 06:11 AM

Quote:

Originally Posted by tom37

If the weather is hot and humid, I set the fan to run on low all the time and the compressor cycles on and off when it needs to.

We do the same!

BayouBoys · 03-25-2015, 04:48 PM

Quote:

Originally Posted by JRTJH

Is only the fan running/shutting off? or is the compressor also running/shutting off?

The fan runs, I can hear the compressor startup then I hear the compressor shut off, then the fan shut's off. It just repeats this cycle. I tried putting it on fan where the fan would run all the time and I got the same result.

As for the voltage, I will have to check that when I can get the camper out of storage.

Thanks for the help.

PARAPTOR · 03-25-2015, 06:02 PM

Wonder if this cycling of the compressor has to do with overheating causing the thermal protect to open shutting off the compressor, it cools thermal protect closes and compressor on again. When you say compressor started did you feel any cool air coming out? Or do you the compressor humming? Not sure why fan is cycling would assume thermostat would control that?

michael_h · 03-26-2015, 09:52 PM

you'd have to be able to measure the compressor amp run draw to start the trouble shooting process to know whether it's a compressor problem, low on charge, or other wise

BayouBoys · 03-30-2015, 05:42 PM

Thanks for the suggestions. I will try these things as soon as I can get out of storage.

Stuka · 04-02-2015, 02:38 PM

Thanks for this thread, I would like to add a couple of AC-related questions if that's all right.

My 2006 Springdale AC comes on and can run fine all day, then other times it trips a breaker. Not sure what is causing that. The electrical panel has a small fan, like a computer fan. When does that fan come on? I have never heard it on....

Does anyone know where I can get more info on that electrical panel?

Edit: Oh, and where is the AC filter located?

PARAPTOR · 04-02-2015, 03:19 PM

Quote:

Originally Posted by Stuka

Thanks for this thread, I would like to add a couple of AC-related questions if that's all right.

My 2006 Springdale AC comes on and can run fine all day, then other times it trips a breaker. Not sure what is causing that. The electrical panel has a small fan, like a computer fan. When does that fan come on? I have never heard it on....

Does anyone know where I can get more info on that electrical panel?

Edit: Oh, and where is the AC filter located?

If you have a 30A system does not take much trip that 30 AMP main breaker which I am assuming you are referring to, rather that the breaker for the AC itself? A Microwave and AC on at same time could be enough to do it.

Think that fan you are hearing is in the power distribution center from the converter and basically runs when the converter is loaded.

Power Panel may be a WFC panel, recommend checking to see who made panel and going to the web for info

AC filter can be accessed from inside should be a door with in the shroud it is only a small mesh clean under water and dry

Festus2 · 04-02-2015, 03:28 PM

Quote:

Originally Posted by Stuka

Thanks for this thread, I would like to add a couple of AC-related questions if that's all right.

My 2006 Springdale AC comes on and can run fine all day, then other times it trips a breaker. Not sure what is causing that. The electrical panel has a small fan, like a computer fan. When does that fan come on? I have never heard it on....

Does anyone know where I can get more info on that electrical panel?

Edit: Oh, and where is the AC filter located?

If you have a 30A circuit and turn on some other high current draw appliance such as the microwave while the AC is running, the breaker may indeed trip because you have overloaded the 30A circuit. This may also happen if the HW heater kicks in or you put on the coffee pot, etc. Running an AC with a 30A circuit means that you have to watch what you have running at the same time.

If by "electrical panel" you mean the converter, then yes, it does have a fan which is there to cool the electrical components when the converter is in operation. Sometimes, if you turn a bank of lights on, that will be enough for the fan to start up since heat is being generated during the conversion from 110V to 12V. If you can't hear the fan, consider yourself lucky.

I am assuming that your converter is a WFCO brand. Downloads of their owner's manuals can be found at www.wfcoelectronics.com

Hope this helps.

Stuka · 04-03-2015, 09:48 AM

Thanks, guys.

Not running the microwave, maybe its a weak breaker. The AC unit will run and cool for 30 minutes with no problem. It seems to trip when it gets to the set temp and cycles off, then on when needed.

Filter, I am guessing it goes here? Under the vented access door?

As for the converter fan, cannot say I have ever heard it, it may not be coming on. Maybe there has been no demand for it to come on. What's the purpose of the convertor? To take 12V battery power and convert to 110? If so, I have only been using 110, so maybe it has not been converting anything

thanks

HappyCamperMN · 04-03-2015, 10:06 AM

Quote:

Originally Posted by Stuka

As for the converter fan, cannot say I have ever heard it, it may not be coming on. Maybe there has been no demand for it to come on. What's the purpose of the convertor? To take 12V battery power and convert to 110? If so, I have only been using 110, so maybe it has not been converting anything

Converter goes the other way. Many systems in the RV work on 12-volt only so the converter takes the incoming 110v AC and charges your battery at 12v DC. Best example of this is lights. If you're using lights, you're using 12v. For that matter, think of anything designed to work while not plugged into shore power. Those systems are either designed to run of 12v DC or propane.

**JRTJH** · 04-03-2015, 10:19 AM

Quote:

Originally Posted by Stuka

Thanks, guys.

Not running the microwave, maybe its a weak breaker. The AC unit will run and cool for 30 minutes with no problem. It seems to trip when it gets to the set temp and cycles off, then on when needed.

Filter, I am guessing it goes here? Under the vented access door?

As for the converter fan, cannot say I have ever heard it, it may not be coming on. Maybe there has been no demand for it to come on. What's the purpose of the convertor? To take 12V battery power and convert to 110? If so, I have only been using 110, so maybe it has not been converting anything

thanks

Yes, the filter is held in place ON the inside of the access door with two rubber bands. If you don't have the filter, it's the typical window A/C dark gray foam filter material that's sold in sheets about 1/8" thick at WalMart and Lowe's. Just cut to fit. It's hard to keep the edges from curling. I tape mine in place with aluminum duct tape rather than use the rubber bands.

To add to the explanation above about the converter. The purpose of the fan is to cool the big transformer and the electronics in the 110VAC to 12VDC "converter". As the electricity is transformed from AC to DC heat is produced. That fan comes on when the DC output increases above a certain level to help keep things cool. If you haven't heard it, probably you haven't had a demand for enough 12 VDC power to trigger it to turn on. As you use more DC power, you'll hear it "eventually"......

Festus2 · 04-03-2015, 11:26 AM

Quote:

Originally Posted by Stuka

As for the converter fan, cannot say I have ever heard it, it may not be coming on. Maybe there has been no demand for it to come on. What's the purpose of the convertor? To take 12V battery power and convert to 110? If so, I have only been using 110, so maybe it has not been converting anything

thanks

Stuka -
Even though you are plugged in to shore power and using 110VAC, you are, in fact, using 12V DC for a number of things in your RV. As mentioned above, your lights run off 12VDC, as well as the water pump, the furnace fan, and the fridge circuitry, to name a few.

So yes, your converter is busy in the background doing what it is designed to do - to change or convert 110VAC to 12VDC.

Stuka · 04-03-2015, 06:58 PM

Ok, I understand, thanks for the explanations!

Stuka · 04-05-2015, 02:11 PM

Last question about ACs

On my 2006 Springdale, the AC is roof mounted. Where does the condenstate go? Is there a pan with a drain to the grey tank? Or is it designed to intentionally run onto the roof and down the side of the camper (like it is doing now?)

**JRTJH** · 04-05-2015, 02:23 PM

It runs onto the roof and finds the low spot and "drips down the trailer wall" at that point. If you can "level your trailer just right" you can get the water to drip into the drip molding along the roof edge and run to the corner where it "could drip" (but probably won't) away from the trailer wall.

Most of us level the trailer so it runs to the road side rear of the trailer. It seems that's the location we walk on the least amount. You wouldn't want it dripping onto the awning and down onto your "activity area". At least, I wouldn't want it dripping there......

Stuka · 04-06-2015, 05:23 PM

Ok, thanks JR, I may see about adding a drain hose to the pan, if I can get to it.

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