A/C not cooling enough for comfort

[riki4570]

We just returned from New Mexico where we needed the A/C most of the time. It was around 95 to 100 degrees outside during the day. (Although it would cool down at night we kept the fan running all night because of the little Chihuahua next door that barked about every 15 minutes! That didn't bother me as much as the raspy voice patiently saying "no" "stop that" or "quiet" after each bark. )
The A/C couldn't cool our trailer down past about 85 or 86 degrees. Are we expecting too much of the A/C unit? Can refrigerant be added to these A/C units like our home A/C? Does it maybe need to be cleaned? We bought it used and haven't really needed the A/C much. Although we live in Arizona, we haven't camped too often in the heat.
Thanks for any tips.

 

[KnottyRig]

A simple test for most any AC is to measure output air temp. It should be as low as 42 degrees (any lower an the system would risk condensate freezing on the condenser coils).

Output air temps above 50 degrees indicates a possible problem and the unit may need servicing.

 

[sam-HILO]

Trouble shooting AC

I have seen DH get up on the roof and remove the AC shroud. I think he blew it out with his compreser,carefully. It does get dirty. Friends in our HiLo club had a bird nest in theirs. What make is your AC? DH also had to remove the shroud from the inside and tighten with a socket set. Becareful not to over tighten. The seal can become loose from travel. Be very careful up on the roof. Last summer we had 90& and 100* days and our AC had to be turned down as it was very chilly. Oursis a Carrier AC. The original one had to be replaced. I'm sure some techy guy will give you some other things to try.

 

[riki4570]

Thanks. I guess we'll plug it in and see what the temp is. Too bad we didn't have our gauge with us on the trip.

 

[riki4570]

Thank you. We have the Duo-Therm Penguin 600 series that is original with the trailer. I think I'll take a look at the filters etc. Tomorrow. Not too sure about getting on the roof. Does DH go right on the roof, or put something on the surface first?

 

[JackandJanet]

Dave, and/or Caryl, I recently returned from a trip to Carlsbad, NM and the temperatures where I camped were a bit above 100 degrees. And, my camp spot (at Brantley Lake State Park) had essentially no shade. As I recall, the temperature inside the trailer was in the lower 80s throughout the day. The A/C froze up once, due to a day with higher humidity, but was fine after I turned it off for about 5-10 minutes. At night, the inside was quite comfortable, but of course the A/C was running constantly.

I don't know if you can expect miracles out of such a small unit, considering the interior volume of the trailer and the very limited amount of insulation. But DO measure the outlet temperature as Knotty suggested and remove the shroud as Sam said to check for dirt accumulation. If you need to blow it out, I'd suggest using a yard blower if you have one. I consider my yard blower to be one of my most useful tools - I blow the dust out of the insides of my computers with mine, and I use it to blow out the interior of my vehicles.

I walk around on the roof of my trailer quite often. I have to get up there to install and remove the cover, and I had to spend time on the roof when I installed my FanTastic Fan and my solar panels. I recall reading somewhere a long time ago that it was built to withstand walking. I weigh about 205# and have never felt any "give" in the roof.

- Jack

 

[Treeclimber]

Perfect, Jack. I'll add that I carry a VERY small shop vac in the outside storage hatch. But I find that I use it more as a blower than a vac. Reverse the hose and use the crevice tip to blow leaves and stuff from around the site. It also worked as stated above with the A/C. The blower/vac also clears clogged drains!
Tree

 

[hilltool]

Jack and Tree:

I never considered using my blower for all of that- a great idea.!

 

[JackandJanet]

A yard blower is great for blowing dirt out of things that don't have fragile parts. I've never had a problem with damage from it on my desktop PCs. I take them outside and make sure the space around them is clear, so I don't push crud into them. About the only thing I'm careful with is the fans - I don't direct air into them for a prolonged period.

You can also blow dirt out of the engine bays of your vehicles. Some vehicles don't like having water sprayed around parts of the engines, so this is an alternative.

- Jack

 

[riki4570]

Thank you all for the tips. We should be able to check out the temp on the A/C tomorrow morning. I'm glad to know the roof will support a person walking around on it. I think both of our blowers are too strong, but I do have a small canister vac that works on DC that I've been meaning to locate in the attic. It may have a blower function and I wanted to get it in the trailer anyway.

 

[JackandJanet]

I run my blower at full speed. Feels like I'm holding a jet engine! I honestly would not worry about damaging anything in the A/C.

- Jack

 

[riki4570]

Thanks, Jack.

 

[sam-HILO]

Fixing AC

Thanks for the reminder to clean the AC filter. I keep an old tooth brush in the RV for this purpose. It works well to get the "lint" off in dry form. Ours has two filters and can ge t dirty with just a weekend of use. Depends on how much you run it. DH is about 165lbs and gets up on our rubber roof with just a step ladder. No additional boards are needed. Ours is a Classic with a Rubber roof.

 

[JackandJanet]

Just to clarify: I would NOT use the yard blower to clean filters. I'm referring to using it to blow off the metal parts outside (the "heat exchanger" or whatever it's called.

Some filters are washable, under running water. Paper ones could perhaps be vacuumed.

- Jack

 

[riki4570]

Finally Plugged the A/C in today.

Finally got to the A/C today. Plugged the trailer cord into a 20 amp outlet in the garage. I know everyone says it needs to be 30 amp, but the fuse in the trailer is 20 amp and we had nothing else operating. Ran the A/C for about 15 minutes. The temp in the trailer was 81. The temp coming out of the A/C got down to 59 using a infrared laser temp sensor to test. I took the inside covers off the filters and cleaned them. They were pretty dirty. There is a small tear in one, about 1/2" right next to the frame. I hope it'll still work. Would plugging it into 20 amp rather than 30 amp cause it to not cool as much? Although we were plugged into 30 amp at the campgrounds and it didn't seem to work any better. Still need to go up on the roof and blow out that part. It's over 100 now, so that'll be a different morning.

 

[sam-HILO]

cleaning filters in AC unit

My filter resemble what you would find in a clothes dryer screen. I prefer a dry clean with a tooth brush when the AC is in use. I don;t think I could put a wet filter back in and use right away.

 

[riki4570]

I cleaned them dry with a very soft tooth brush, then rinsed them. They are drying as I send this note. Shouldn't take long, it's very warm in the garage.

 

[KnottyRig]

Riki - here's the "deal" with different circuit specs.

When an electrical circuit is *properly* designed, the breaker will be sized according to the gauge/run of wire. The lower (numerical) gauge of wire, the thicker the wire, and the more current it can support.

IIRC, 14ga copper is good to 15 amps (very common breaker/wiring for household outlets). It'll require numerically lower gauge (12 or 10) for higher current loads (20A/30A). Don't hold me to these, there's a national code and state code that specify these things.

When a circuit is spec'd to a certain current load, the closer you get to that current load, the more the wiring heats up, the greater the resistance becomes, and the less efficiently it can deliver that current. Which is why sometimes a circuit rated for a given load may blow the breaker when a load approaches that limit, or is continually running at a high percentage of that limit, or spikes the current demand (all of these describe AC units).

Also if there are any other loads on that circuit, or other loads on that electrical panel, or the electrical service is nominal, or the wiring is less than ideal, the breaker is old, the AC unit is old, it's start capacitor worn, compressor worn, etc, etc, it can easily overwhelm the (nominally sufficient) breaker.

Add to this the quality of extension cord makes a huge difference - a smaller gauge cord will heat up faster, driving up resistance, increasing the total current required through the entire circuit to start/run the AC.

So while the breaker in the trailer for the AC may be 20 amp, just because the AC itself isn't drawing 20 amps through that breaker doesn't mean that the house wiring *isn't* seeing a 20amp+ load (due to the cord, other loads, etc), especially during AC startup.

So using a 30 amp circuit in the house just helps reduce the likelihood of having overcurrent problems, given the wide variety of wiring quality, loads, AC condition, extension cords, etc.

 

[KnottyRig]

The temp coming out of the A/C got down to 59 using a infrared laser temp sensor to test.

As a general rule of thumb (due to heat exchange rate of air) the lowest temp you can get a space cooled to is about 20 degrees above the AC outlet air temp. Which is why a target for AC outlet is mid 40's.

59+20=79, not too far off your 81.

59 degrees is too high - something isn't quite right. Finish cleaning and test again. Dirty coils/plugged ductwork/dirty filters (such as there is on these things) can cause poor performance. Though at this high of a temp I'm thinking it's going to need to be serviced. But hey, you could get lucky and find a squirrels nest covering the condenser!

 

[riki4570]

Thanks, KnottyRig for all the info. Blowing off the outside is next on my list. The 81 inside the trailer is just the air temp early in the morning, no air on. We only ran the A/C for around 10 or 15 minutes for the initial test. The cord and plug we plug in for the A/C, in the front of our bedroom, always feels warm to hot when the A/C is running even when we're hooked up to 30 amp at a campground. I'm not sure if it should. Maybe the cleaning will help that, or maybe it just needs servicing. We've never had it serviced and who knows what the PO did in the way of maintenance (although I know he didn't do a good job of cleaning out the black water tank before trading the trailer in!)