Main Cabin AC Running but not really

[tarbabi]

I know that is a strange subject line but, that is just it. Zone one which is the main cabin will fire up, the compressor will kick in, but the fan never seems to change speed. No matter the speed I set it to it never changed. Never could get it below 80 degrees. The air that it was blowing was cool. So this evening I cleaned the coils and retaped the supply and return cutouts on the roof. Very poor taping to say the least. Fan motor is oiled and spinning freely. Will wait till tomorrow when it is dry to fire it back up.

Any thoughts??

[calewjohnson]

In addition to taping the air box, I doubled the size of the return vents and added actual 12x12 filters. I also changed all the ceiling vents to Space port vents...Venting Products / AC Vents / "Spaceport" #8841 Fully Adjustable RV AC Ceiling Vent - DW Inc.

I also drilled a hole and added another vent in the main living area. It can get quite chilly now.

Cale

[tarbabi]

Cale, can you hear your fan in the main cabin changing speeds??

[calewjohnson]

Yes I can...however, the fan speed change is based on some stupid algorithm that Dometic dreamed up, and it really makes me mad...


If the temperature split (as defined as requested set temperature and actual inside temperature) is greater than 8 degrees, it will blow on high.


It will blow on medium if the temperature difference is 3 or 4 degrees.


otherwise it is low. I wished it was user selectable, I would rather have it cool on high all the time, as it basically runs constantly...


Cale

[tarbabi]

Thanks. New vents ordered this morning.

[joebedford]

The cooling in the main area of my 3950 is really poor. I made some improvements but need to pull the unit off the roof to retape the return. Also replace the vents.

[tarbabi]

Got the unit put back together and man did cleaning the coils and retaping the return make a huge difference. New vents will be here on Thursday. Thanks for the tips.

[calewjohnson]

Originally Posted by tarbabi

Got the unit put back together and man did cleaning the coils and retaping the return make a huge difference. New vents will be here on Thursday. Thanks for the tips.

Did you use any chemicals to clean the coils or just running water? I saw some spray and Lowe's that is for cleaning coils, but I would hate to spray it to clean the coils, then have it eat through my roof.

Cale

[tarbabi]

Yes I used the coil cleaning solution. I found mine at an Ace Hardware. I did move the unit to the side as not to get water in the ducts. Spray in and let it work for five minutes and hosed it off.

[TomW]

Cale, Where did you add the additional AC Vent? I've done all the other vent checks and mods but this sounds like the icing on the cake! Thanks

[calewjohnson]

Originally Posted by TomW

Cale, Where did you add the additional AC Vent? I've done all the other vent checks and mods but this sounds like the icing on the cake! Thanks

In my 3950 there were only two vents in the line closest to the couch slide, one next to the loft and one near the bedroom door. I split the difference and drilled a four inch hole in the ceiling, taped it, and added one of the spaceport vents. With it pointed towards the couch, it can get frigid in the slide area.

Cale