Basement A/C

[JPMaly]

I am posting this in the Winnebago forum because my 2003 Jayco Avatar is very similar to the Winnebago Journey, basement air. Its not cooling enough, 50 degrees out the vents and 62 degrees into the air intake. Cleaned coil and installed vents that can be closed off in an attempt to cool down half the coach. No dice. Also have black streaks coming from the rear vents. I am aware of the problems with the vertical ductwork. However, my coach has spray foam covering the ducts in the rear. I have not had the ac unit checked if both compressors are working, as I am inclined to believe the dirty vents need addressing first. Any opinions on how to proceed? Thinking maybe its leaking somewhere near the ac unit itself or maybe more foam? The thought of removing the rear cap makes me nauseous. So does the thought of new roof ac units.

[lajuene]

I've been told the air temperature out of the vents should be 20 degrees below the outside temperature. 50 degrees out of the vents is ok if outside temperature is around 70. We had huge leaks behind the rear cap and I taped and sealed them and it was much better.

[lajuene]

Our Coleman Mach basement air unit is only 4 years old but we just had the outdoor blower motor go bad and had it replaced. Otherwise it's a run great for those 4 years and we're full-time so it gets a lot of use.

[Duner]

Do you have a way to measure the amps on the 117 vac from shore power?

There are two compressors and if both are working the amp draw should be around 23 amps. If only one is running the amp draw will be 12-14 amp. Since you're only getting 12 degree drop in temp seems like only one compressor is running. There are lights on the control board to tell status of each compressor power wise. Also, if a compressor has lost freon, it won't cool and it won't draw as many amps as if it was working normal.

There is a very detailed troubleshooting guide in the Coleman Service Manual. You can download it from my website here.

I also have a detailed procedure how to pull the unit out (on a Winnie) and deal with some of the most common failures inside. You can download it here.

OBTY, the 20 deg temp differential is inside intake to inside output vent temp and is not based on outside temp.

Are you sure you don't have any leaks in rear cap. I've been fighting leaks for many years and it really reduces the efficiency when it's darn hot outside. Use an infrared temp gun to look around for cold temps up there.

Good luck,
Bill

[Ranger Smith]

62 degree air going in and 50 out. Are you trying to turn it into a freezer. Im not an AC expert but at 62 degrees there is not a lot of heat to remove from the air.


Quotes from AC Searches



The design of virtually all air conditions assumes that the system is not going to be run when the temperature is below 60 degrees Fahrenheit, since it is below the comfort area of most people.


Did you know that most air systems are not used properly and ... Each central air system works to cool air by 15 to 20 degrees at a time.

[JPMaly]

Last summer in Austin the coach refused to get below 90 degrees inside. Outside was 98-102 during our month long stay. RV park had metered electricity and the lady said, "gee you used a lot" and then handed me the bill. I will check my numbers again as it was only about 75 degrees outside when I got 50-62 readings. Question, are the vents in your Winnies covered with spray foam like mine? And do you think respraying might work? Thanks

[Ranger Smith]

Originally Posted by lajuene

I've been told the air temperature out of the vents should be 20 degrees below the outside temperature. 50 degrees out of the vents is ok if outside temperature is around 70. We had huge leaks behind the rear cap and I taped and sealed them and it was much better.

Its not the outside temperature. It is the ambient air inside the rv being sucked into the supply vent.


If it were 80 "outside" and inside air was being blown out 60 then it went up to 90 outside then you are saying air out of ac woild be 70.


As the air in the coach cools the air coming out of the vents cools.

[Duner]

Originally Posted by JPMaly

Question, are the vents in your Winnies covered with spray foam like mine? And do you think respraying might work? Thanks

No spray foam on Winnies, just 1/4 in thick insulating pad sealed with aluminum tape that can dry out and come loose.

I wouldn't re-spray unless you find cold air leaking out (using the laser pointer on a temp gun). Do you have one? If not they are only $25 at Harbor Freight (HERE).

[JPMaly]

Harbor freight, here I come. Thanks!

[Unicorn Driver]

Originally Posted by Duner

No spray foam on Winnies, just 1/4 in thick insulating pad sealed with aluminum tape that can dry out and come loose.

I wouldn't re-spray unless you find cold air leaking out (using the laser pointer on a temp gun). Do you have one? If not they are only $25 at Harbor Freight (HERE).

Hi Duner,

Can one tell if there is a leak with an infra gun?
I ran one across the back if my coach and there was no temp differences, does that mean no leak?

[tmw188]

You can also buy an inexpensive clamp on amp meter at HF but you will need to open up your transfer switch to clamp it on the black wire and then the red wire to see if they both are reading about the same with all other loads off except the ac unit. Do you by chance have a Progressive Ind. EMS with the display monitor it will give readings for line 1 & 2 also. It is very obvious especially outside when the unit comes on from being off when the second comp comes on.

[Duner]

Originally Posted by Unicorn Driver

Hi Duner,

Can one tell if there is a leak with an infra gun?
I ran one across the back if my coach and there was no temp differences, does that mean no leak?

No, checking the outside temp of the cap won't tell you anything unless you had a really big break in the duct.

You have to get underneath and look up at the duct work and extend your arm to get the temp gun as high up as possible. Then go up and down the seams with the laser while reading the display for temp drop.

[Fletcher0077]

I did find leaks in the duct underneath the back cap. There were 2-3 leaks and difficult to find. It's awkward to do but I taped a tissue to a broom handle and put it up next to the duct with the fan running. That indicated where the leaks were. Then reaching it with an alcohol damp cloth to clean old foil tape wasn't a pick-nick either. I can somewhat sit up beneath the cap and reach up with my finger tips about 4 feet up the duct. Fortunately none of the leaks were higher than that. Applied new foil tape and again checked for leaks. Once the tissue didn't wiggle I was done.

[Unicorn Driver]

Originally Posted by Duner

No, checking the outside temp of the cap won't tell you anything unless you had a really big break in the duct.

You have to get underneath and look up at the duct work and extend your arm to get the temp gun as high up as possible. Then go up and down the seams with the laser while reading the display for temp drop.

Thanks Duner,

I will try that.