intermittant a/c cooling

[Strawman]

Every now and then my Duotherm a/c will freeze up. It did it yesterday with ouside temp of 80 degrees and inside set at 70. If I leave it set at 75 its OK no matter what the temp outside is. But set it at 70 and it chokes.

If it freezes and I let it unthaw, it works again. Is this a problem as to why I can't cool to 70? I would like it to cool as I currently have to run 2 aux fans when its set on 75 as the bedroom gets hot.

[Strawman]

Every now and then my Duotherm a/c will freeze up. It did it yesterday with ouside temp of 80 degrees and inside set at 70. If I leave it set at 75 its OK no matter what the temp outside is. But set it at 70 and it chokes.

If it freezes and I let it unthaw, it works again. Is this a problem as to why I can't cool to 70? I would like it to cool as I currently have to run 2 aux fans when its set on 75 as the bedroom gets hot.

[OCDUNE]

I don't have experience with RV units, but on a residential unit, freezing is most commonly caused by a dirty air filter or being low on freon.

OCDUNE

[TXiceman]

90% of the time freeze ups in an RV A/C is caused by low air flow. Either dirty coils/filters or fan operating on low speed. I wish they would do away with the low speed setting on the A/C units.

Occassionally one will be low on "Freon". A fast check to see if you are running normally is to set the AC for a low enough temp to keep it running for about 10 minutes. Make sure the filter and coils are clean, and fan on high speed. Take a temp reading right out of the duct. and them take on where the air is returned to the unit. You should get 15 to 20 dF difference. 15 dF is OK, 25 dF is doing great. If out of these ranges, you probably do have a problem.

Best of luck...

Ken

[Strawman]

Thanks gents. Is there a special cleaning product available for cleaning the coils. Since I'll be giving the trailer a good scubbing this weekend I might as well pull the a/c cover off and scrub it down also.

[Fulltimer]

The "coils" in question are inside your rig.

[TXiceman]

You can buy a foaming coil cleaner from an A/C wholesaler. It can be used on both the interior and exterior caoils. The coil I was refering to is the evaporator coil, inside the unit. It is difficult to reach and clean.

Ken

[Frankenstien]

There is one other thing to check, on your condensor coils you will see a sensor attatched...make sure its still attached, you may want to relocate it to a more central loaction on the coils also, this will alow the compressor to cycle less and may help in reducing the "freze up"

[powerboatr]

one other item you may want to check
like most newer rvs we have ducted a/c, last summer we noticed the not so cool thing at 75 or so. As i was cleaning the return duct and fliter i noticed a few air gaps that were unsealed from the outside air, patched them up with a/c duct foil sticky back tape.
then i removed each register in the ceiling, even the screws and the housing.
I was amazed at the amount of HOT air i felt from around each vent opening. when they punched the holes for the vent registers they did just that, PUNCHED holes. and not even in the center of each duct, one was half and half of vent and attic, so i again got my handy a/c duct foil tape and made my ducts airtight from out side influences.
we used to have to have both a/cs on to cool the coach.
after that i had to turn one off and down to low, it gets very cold now and the filter doesnt get near as dirty as quick.
. made a world of difference