basement air question

[pattcook]

I measured the air temp coming out one of the ac ceiling vents in my 35u Itasca and its right at 63.5 degrees. I measured the same vent in my two friends coaches( same coaches) and they get down to 53-54 degrees. Can these basement ac systems be charged? My filter is new. I can,t think of anything else to check. That 8-10 degree difference makes a world of difference. Any suggestions?-Thanks John

[Pelledan]

Your basement air probably has two compressors and either one is dead, the system is low on refrigerant or an air filter is clogged. Take a look at the power draw on your one place when the a/c is energized. You will see a spike in power consumption that should level off at about 18 amps. Once it levels off, you will see another power spike when the 2nd compressor kicks in and the power will stabilize at around 24-26 amps. If you see only one power spike, one of the compressors is dead. If you see the double spike, then you will need to check the filters or the refrigerant charge. The entire basement air system is a sealed unit, but it is completely servicable including compressor replacement. Adding refrigerant will require breaking into the sealed lines and adding a service valve to recharge. This requires special tools, equipment and knowledge to perform the job safely and accurately.
Dan

[edgray]

Originally Posted by pattcook

I measured the air temp coming out one of the ac ceiling vents in my 35u Itasca and its right at 63.5 degrees. I measured the same vent in my two friends coaches( same coaches) and they get down to 53-54 degrees. Can these basement ac systems be charged? My filter is new. I can,t think of anything else to check. That 8-10 degree difference makes a world of difference. Any suggestions?-Thanks John

Very interesting. If the other two "same " coaches are still available to you, can you please also get the temps at their return inlet (filter) ???

We've been told repeatedly that ~20 degrees temp differential between output and inlet is the best we can hope for. I think it would be interesting to determine if that is true for these other coaches that seem to be running much colder than yours. I'm also told the systems need to be running at least an hour, with the fan speed set on high, and the thermostat set several degress below the room temperature to assure that both compressors are being used.

To answer your question, YES they "can be" charged, but an A/C tech will need to solder in the schrader-type valve needed to attach his charging hoses. THAT may require the unit to be removed from the coach-I'm not sure- but that is what they did to mine when they found a leak.

Please let us know about the differential temps if you can get them.
Ed

[edgray]

Originally Posted by Pelledan

Your basement air probably has two compressors and either one is dead, the system is low on refrigerant or an air filter is clogged. Take a look at the power draw on your one place when the a/c is energized. You will see a spike in power consumption that should level off at about 18 amps. Once it levels off, you will see another power spike when the 2nd compressor kicks in and the power will stabilize at around 24-26 amps. If you see only one power spike, one of the compressors is dead. If you see the double spike, then you will need to check the filters or the refrigerant charge. The entire basement air system is a sealed unit, but it is completely servicable including compressor replacement. Adding refrigerant will require breaking into the sealed lines and adding a service valve to recharge. This requires special tools, equipment and knowledge to perform the job safely and accurately.
Dan

FWIW, I completely agree with everything in this excellent post by Dan.

Regarding the second compressor, if you don't "see" its amp draw spike, then please check the circuit breakers before assuming the compressor has failed.........you don't need to know how far I drove to get mine repaired (after determing it was "dead") only to be shown a tripped breaker. Very expensive lesson learned.
Ed

[pattcook]

Originally Posted by edgray

FWIW, I completely agree with everything in this excellent post by Dan.

Regarding the second compressor, if you don't "see" its amp draw spike, then please check the circuit breakers before assuming the compressor has failed.........you don't need to know how far I drove to get mine repaired (after determing it was "dead") only to be shown a tripped breaker. Very expensive lesson learned.
Ed

I see the 2nd spike when the second compressor comes on. I can,t really measure anything but the air coming out of the vents. Funny but my one friend with a 33 adventurer has 2 air filters. I only have one. Wondering what others have?- I,m getting 61.7 out of the vent now but thats still almost 8 degrees higher. Both these other guys are in the hi 53 range.- John

[tomsm]

John - A common point of failure on the basement air systems is the vertical duct carrying the cooled air up the back of the coach to the ceiling vents. It tends to split along the corner of the taped together box duct. When this happens the symptom is the reduced cooling like you are seeing.

Mine did it recently at about 7 years of age. It was a very easy fix with metalized tape as the rear of the diesels is more wide open and easy to get to the duct.

There are several threads on repairing duct splits inside the rear cap on gassers.

If you lie under the back toward the passenger side, you should see the duct going up the back wall. With a good, strong light, you should be able to visually check for a split. Reaching up inside the cap, you should also be able to free a cool breeze if it is split.

May not be the problem, but since you didn't mention it, it's one more thing to check...

[tomsm]

John - If you find the duct to be your problem, here's a link to a thread about fixing it. There are links to other threads within this one, some with pix...

[Dwonner]

It also could simply be that your condesors need cleaned. There are 2 and to properly clean them the unit needs to be pulled out. It is a job that can be done in an afternoon if you are comfortable working on such things.

[pattcook]

Originally Posted by Dwonner

It also could simply be that your condesors need cleaned. There are 2 and to properly clean them the unit needs to be pulled out. It is a job that can be done in an afternoon if you are comfortable working on such things.

I just crawled under the rear cap and looked up at the square ductwork. The sheathing around the duct has seperated and opened and there appears to be a fairly large area where the air is escaping. I,ll try and make a repair when I get off this trip. Have those that have had this problem and repaired it noticed any difference in their ac performance? thanks- John

[cbeierl]

Originally Posted by pattcook

I just crawled under the rear cap and looked up at the square ductwork. The sheathing around the duct has seperated and opened and there appears to be a fairly large area where the air is escaping. I,ll try and make a repair when I get off this trip. Have those that have had this problem and repaired it noticed any difference in their ac performance? thanks- John

Yes, re-sealing the duct work will make a significant difference in how effectively the AC systems cools the coach.

[smlranger]

Originally Posted by pattcook

I just crawled under the rear cap and looked up at the square ductwork. The sheathing around the duct has seperated and opened and there appears to be a fairly large area where the air is escaping. I,ll try and make a repair when I get off this trip. Have those that have had this problem and repaired it noticed any difference in their ac performance? thanks- John

Absolutely. You will see a significant improvement.

Once you have fixed that leak, run the AC for about an hour and make sure the T-stat is set well below the actual room temp. Check the air temp at your return and then at the first discharge vent in the ceiling. The differential should be at least 20 degrees.

[pattcook]

Originally Posted by smlranger

Absolutely. You will see a significant improvement.

Once you have fixed that leak, run the AC for about an hour and make sure the T-stat is set well below the actual room temp. Check the air temp at your return and then at the first discharge vent in the ceiling. The differential should be at least 20 degrees.

I got home this morning and spent about 2 hrs taping up the ductwork. I had multiple leaks around the u joint coming out of the ac unit as well. What a difference. Measuring the same outlet as yesterday I am down to 54.5 degrees where at the same time and outside temp as yesterday I was 63-64. Thankyou to those that guided me thru this. Like others have said its a shame to have lived with this for so long. Hope my tape job holds. Its a chore getting up in there. But at least I know how to repair it now. thanks again.- John