Basement Air running intermittently

Our basement Air conditioning on our Horizon 40AD is running intermittently.  I have the thermostat set to 72.  The temp reading is 74.  It runs for several minutes then stops.  After a couple of minutes it start up again, never reaching the 72 degree setting.  Any ideas?  Is there some kind if limit switch that may be causing it to shut off?  Is it impacted by the outside air temperature that is presently 65.

We are presently in Tucson and the AC has been running very well until this evening.

Yep...I've had several posts (elsewhere, but not supporting that site any more) on this problem, and indeed it is a problem.   

Here is some of my posts in the thread I had started on this situation.....see if our problem is similar:

My Basement air cools the coach off good with both compressors running continuously at an outside temp of above 80 degrees....

Once the outside temp gets down to under 75 degrees, the compressors come on and then go off after a couple of minutes, then both come back on, then off again....

Set point of 60 degrees...

This seem normal?

Also, another one from me:

Yeah...once the outside temp reaches below the mid 70's, the compressors short cycle even though the inside is 76 with set point of 60...seems like both compressors should still run continuously exclusive of what the outside temp is.....

Above 80 degrees outside temp, both compressors run and the air in the vents is 45 degrees....so there sounds like there is plenty of refrigerant....

Another one from me on the same thread, and I think this NAILS your problem:

Mine is still in the shop for the original problem reported in this post.

The compressors short cycle when the OUTSIDE ambient temperatures are below 75 degrees....

Im not sure I have convinced the service dept at my dealer to jumper the outside thermistor, which I and TheRVGuy thinks it is....they seem to think its inside somewhere...air flow......I disagree....

The dealer just received a 2007 Voyage in, and they report it has the same problem...Im beginning to wonder if we ALL have the above problem...just not too many people run their air below 75 degrees, so they dont notice???

After several comments, here is the post of the RESULTS of what I did to remedy the problem:

I got my unit back from the dealer, and they moved the cooling thermistor to the outside of the inside coil for better air flow, and it appears to have solved the problem somewhat as now my basement air compressors run now when the OUTSIDE ambient temps drop below 75 degrees....The air flow out of the vents does appear to be somewhat weak, and the dealer says that also, and they believe the inside condensor will freeze up sometime especially since now the thermistor is now moved....I can live with that though...

Also after a trip after the repair, this is what I posted:

Update on my original post.

We just got back from a 2,800 mile trip through some very hot areas, and the air conditioner coil didn't freeze up (even with the thermisor moved), and the compressors ran fine below the outside ambient temp of 70 degrees or so (original problem)....

Hope this helps!   

Is 45 degree air at the vent indicative of enough refrigerant?  Just curious, as my basement unit seems to struggle until outside air temp comes down pretty close to set temp.  I checked outlet air temps while running the AC while parked in a shady spot and got 45, and your temperature reading caught my eye as it was the same as mine.

Does the basement unit have to be dropped to add refrigerant, and what kind does it take?

roadking52 said:

Is 45 degree air at the vent indicative of enough refrigerant?  Just curious, as my basement unit seems to struggle until outside air temp comes down pretty close to set temp.  I checked outlet air temps while running the AC while parked in a shady spot and got 45, and your temperature reading caught my eye as it was the same as mine.

Click to expand...

20-30 degree differential from return air to outside air is normal

Does the basement unit have to be dropped to add refrigerant, and what kind does it take?

Click to expand...

Unfortunately yes.  Most likely R22 refrigerant.

Today my AC worked perfectly.  Temps in the low 80's here in Tucson.

John, a little tidbit here..

20-30 degree differential from return air to outside air is normal

Click to expand...

All RV A/C's do not use outside air supply; they re-circulate the air from the RV inside (doors and windows closed). Therefor, when the ambient inside temp is 80 deg. the vent output temp will be about 60 deg. Then, when the temp drops to 70?. the vent temp will be about 50? etc, etc. There will be a limit to how cold it can eventually get.

  Only with the in-dash A/C one has a choice, use outside air or re-circulating, switchable.

Hope I didn't ruin your day. 

carson

Yup - I agree!  The 20-30 degree differential for our purposes is more of a rule of thumb for AC performance.

LK23 said:

Today my AC worked perfectly.  Temps in the low 80's here in Tucson.

Click to expand...

Well of course it did...wait until the outside ambient temps drop below 70 and see if your compressors run....my bet is they don't run.

LK, sounds normal to me. If the outside temp is 65? just open a window and a roof vent and you'll have what you want. RV A/C's are designed with people in mind, not refrigerating sides of Beef.  ;D

carson

roadking52 said:

Is 45 degree air at the vent indicative of enough refrigerant?  Just curious, as my basement unit seems to struggle until outside air temp comes down pretty close to set temp.  I checked outlet air temps while running the AC while parked in a shady spot and got 45, and your temperature reading caught my eye as it was the same as mine.

Does the basement unit have to be dropped to add refrigerant, and what kind does it take?

Click to expand...

It is a sealed system and if freon has to be added they will have to add fittings to do that. I had to do it on my old unit and had the ac man run the (4 fittings, 2 comp with a high and low fitting on each comp) to side wall and mounted perm. To access the fittings for the gauges I just opened the compartment door in front of the unit and they were right there,btw the unit could still be removed with this added feature. As far as removing the unit it is a piece of cake with (I believe his name is bill duner) instructions.  I did it by myself in less than 45 min but would be much easier with 2. These instructions are so good I made 2 copies for myself and suggested to this site adm to make it a perm sticky.  good luck

winnie35 said:

(I believe his name is bill duner)

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That's my boy Bill Elsenpeter (aka Duner) - Bill is a retired electronics engineer; thinks like an engineer, acts like an engineer, and writes documents like an engineer 

John Canfield said:

That's my boy Bill Elsenpeter (aka Duner) - Bill is a retired electronics engineer; thinks like an engineer, acts like an engineer, and writes documents like an engineer 

Click to expand...

Hey, I resemble that remark! ... I think?:  Just because I toot the horns at the intersections. ;D
Well, it's coming up on 1 year since I repaired my basement unit, and it is working like a champ.  I'm here in central Florida where the UV rating is 15 out of 16, I'm using the a/c about 6-8 hrs everyday.  It'll be time to head north in another week or two.

Take care,
Bill

John Canfield said:

That's my boy Bill Elsenpeter (aka Duner) - Bill is a retired electronics engineer; thinks like an engineer, acts like an engineer, and writes documents like an engineer 

Click to expand...

  John, I respectfully disagree. Having worked for AT&T for over 30 years and dealing with eng I wouldn't cuss him that way. Just kidding,Just kidding, my father in law was one of the best civil eng around and fought in three wars to boot.

LK23 said:

Our basement Air conditioning on our Horizon 40AD is running intermittently.  I have the thermostat set to 72.  The temp reading is 74.  It runs for several minutes then stops.  After a couple of minutes it start up again, never reaching the 72 degree setting.  Any ideas?  Is there some kind if limit switch that may be causing it to shut off?   Is it impacted by the outside air temperature that is presently 65.

We are presently in Tucson and the AC has been running very well until this evening.

Click to expand...

Please report back when the outside temp is below 70 or so and you try to run the air conditioner.  thanks!

If the cooling thermister hasn't been moved to the outside of the inside coil, where would it be visible after removing the filter at the side of the bed?  I don't see anything under the filter but since Forest City was supposed to have fixed my intermittent cooling problem maybe they did move it.  I only have problems with the compressors running intermittently while camping around 9,000 feet in the Colorado mountains. 
Someone mentioned to just open the windows and roof vents when cooling is needed with outside temperatures around 70 degrees or lower.  That works fine if the air isn't full of black smoke from the coal burning trains going thru town,  or the wind isn't  blowing 25-40 MPH down a dusty street.

Wagonmaster2

Wagonmaster2.  It's me, that you have been having this chat yesterday about our air conditioners   ;D

First, glad to see you here, and second....yes, it was you and I that had this conversation "over there" (FrontrangeRVer) last year about this subject, and both of us had the same problem:  compressors wont run when outside ambient temps are below 70 degrees.  Im not sure altitude has anything to do with our problems, as it didnt matter whether I was in Austin or Aspen, with the outside temps below approx 70, the compressors would click off without satisfying my set thermostat set point.    

Here is the kicker:   I believe ALL WINNEBAGOS with basement air have this problem, and owners just flat don't notice it.  Like I said in one of my threads over there, there was another Winnie owner with his unit in the shop at that time that had the same problem, as he and I didn't open our windows much at night, so we depended on the air to cool us, and it didn't.  I would like to hear from LK23 when this happens to him again.

If you take out your filter, and lean down and look at your inside coil and DONT see your white wire with thermister (small metal thermometer) sticking in to the coils, they moved your thermister to the other side of that same coil, and to see that entails sliding out your basement air to check.

And yes....the above mentioning of not running the air when outside temps are below 70 doesn't work with me either....it could be 70% humidity outside, or smoky, or loud, so we rarely open our windows unless we are high in the mountains and the outside temps are below 65 or so.   

As an after-thought, does anyone know if this intermittent on/off of the compressors can be doing unnecessary harm or wear to the compressors?  Should we allow this to go on once we realize what is happening and shut the air conditioner off?  Or do we just allow the compressors to keep their intermittent running with the hope the inside temperatures will eventually drop a little?
Maybe this situation is no problem since that's the way our car air conditioners control the temp by cycliing on/off while driving down the highway.
Do we have any air conditioner experts on the Forum?

Allen

Allen - it is (or at least was) easy to talk to an RVP tech at the factory, so that would be my choice of the ultimate authority to answer the question.

My thoughts are the start capacitors are taking the brunt of the start surge current and can and do fail; fortunately that they are easily and inexpensively replaced.

Here's an update. 

Tonight we are in Albuquerque.  It is 75 degrees inside our coach and 72 degrees outside.  I attempted to run the AC to bring the inside temperature down before going to bed and it is short cycling again.  I guess this is normal for the basement air.

Rex - give RVP a call and ask if that's normal.