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 > Air Conditioning Malfunction?

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wa8yxm

Wherever I happen to park

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Posted: 07/21/19 06:33am Link  |  Quote  |  Print  |  Notify Moderator

Branson N Tucson wrote:

I believe that if you are only on 30 AMP only one unit at a time will run. 50 AMPS both will kick on.


True but the fans on both may run. (Depending on how it controls them)

Second To the O/P when was the last time you cleaned the condener coils.. often they get a touch ...er... clogged with stuff?

(Mine were last leaned last thursday)

FInally. how did you measure the cooler air. Dont expect 35 degree air if the room is 90 as they can only drop the temp 20-30 degrees in most cases. And high outside temps will reduce effiency as well. and it has been HOT OUT


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obiwancanoli

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Posted: 07/21/19 07:52am Link  |  Quote  |  Print  |  Notify Moderator

wa8yxm wrote:

Branson N Tucson wrote:

I believe that if you are only on 30 AMP only one unit at a time will run. 50 AMPS both will kick on.


True but the fans on both may run. (Depending on how it controls them)

Second To the O/P when was the last time you cleaned the condener coils.. often they get a touch ...er... clogged with stuff?

(Mine were last leaned last thursday)

FInally. how did you measure the cooler air. Dont expect 35 degree air if the room is 90 as they can only drop the temp 20-30 degrees in most cases. And high outside temps will reduce effiency as well. and it has been HOT OUT


Condenser coils have not been cleaned... new (2017) rig, this was the first time the a/c was actually used.... I measured the "cooler air" by standing under the vent so that the air flow blew directly on me, and compared THAT cool to the cool coming from the dash a/c, which was noticeably colder air flow... huge difference!

Walaby

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Posted: 07/21/19 08:09am Link  |  Quote  |  Print  |  Notify Moderator

If you hear the compressor kicking on, get a infrared thermometer.

Measure the temp of the air intake, and then measure the temp of the air coming out of the vents. Should be about a 20 degree or so difference. That's probably the first thing the tech is going to do.

Crawl up top and remove the cover. See if coils are clean.

Mike


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dougrainer

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Posted: 07/21/19 09:12am Link  |  Quote  |  Print  |  Notify Moderator

Walaby wrote:

If you hear the compressor kicking on, get a infrared thermometer.

Measure the temp of the air intake, and then measure the temp of the air coming out of the vents. Should be about a 20 degree or so difference. That's probably the first thing the tech is going to do.

Crawl up top and remove the cover. See if coils are clean.

Mike


You CANNOT use an IR Thermometer to sense AC air temp. Period! IR only senses solid objects and cannot sense air temp. You must use a digital thermometer to test the air temp. Dash Air will get colder output air than Roof AC temps. By about 10 degrees. Doug

Walaby

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Posted: 07/21/19 10:51am Link  |  Quote  |  Print  |  Notify Moderator

Hmm... So, good point. The IR thermometer is probably measuring the temperature of the physical intake and the physical output vents, not the actual air temp. Still, when I use mine, it does show a 20+ degree difference between the two physical objects, which would still provide a relative eval, although as you say it wouldn't be an accurate measure of the air temp.

Mike

obiwancanoli

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Posted: 07/25/19 09:33pm Link  |  Quote  |  Print  |  Notify Moderator

A/C still not working properly, but could this be suspect?

When I bought my rig 11/17, I was told by the dealer that the house batteries required no maintenance, and so, I ignored having to check them. In the time I've had my rig, there have been issues with the duration of power when not connected to shore power, forcing me to run the generator more than expected...

As a matter of routine, I checked the compartment, wanting to make sure the gauge on the propane tank was accurate, and behold, there was a small amount of corrosion on a couple terminals of these deepmcycle batteries, and further, I noted there were removable caps on the cells... so, I checked them, and... dry as a bone, every battery. Filled each cell with distilled water, a little more than covering the plates, and we'll see if that improves things.

Made me wonder if they were not producing enough power to fully run the a/c... thoughts? Concerns? Have the batteries become too damaged to avoid replacement? Haven't tried the a/c, it's evening, but the weekend will be hot, so going to give it another go...

dougrainer

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Posted: 07/26/19 06:16am Link  |  Quote  |  Print  |  Notify Moderator

obiwancanoli wrote:

A/C still not working properly, but could this be suspect?

When I bought my rig 11/17, I was told by the dealer that the house batteries required no maintenance, and so, I ignored having to check them. In the time I've had my rig, there have been issues with the duration of power when not connected to shore power, forcing me to run the generator more than expected...

As a matter of routine, I checked the compartment, wanting to make sure the gauge on the propane tank was accurate, and behold, there was a small amount of corrosion on a couple terminals of these deepmcycle batteries, and further, I noted there were removable caps on the cells... so, I checked them, and... dry as a bone, every battery. Filled each cell with distilled water, a little more than covering the plates, and we'll see if that improves things.

Made me wonder if they were not producing enough power to fully run the a/c... thoughts? Concerns? Have the batteries become too damaged to avoid replacement? Haven't tried the a/c, it's evening, but the weekend will be hot, so going to give it another go...


Sorry, your assumption is not correct. While it TAKES 12 volts to operate the wall Tstat controls, the AC's run off 120 volts. So, 12 volt fluctuations will not cause your AC problem. You need to REPLACE the batteries. Once they boiled dry, they are useless. They may come back up, but they will never get to 100% operation. Doug

obiwancanoli

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Posted: 07/27/19 04:37pm Link  |  Quote  |  Print  |  Notify Moderator

OK, here's a new development... I'd been trying the a/c a few times since my initial post, withalways the same results - no a/c... listening for the compressor(s) to come on, and it never did... So, today, I'm back in the same situation, only this time, I'm watching the display on the control unit, which for a Dometic unit, shows "E7" - an error code... so I look up the error code, and the manual states as follows: "Loss of 120 Vac power to all power module boards on the system. The system will shut down."

Now, I've checked the circuit breaker (20A), turned it off, then back on again...still no a/c... what else should I be checking?

down home

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Posted: 07/27/19 05:32pm Link  |  Quote  |  Print  |  Notify Moderator

Twenty amp circuit breaker is not larg enough. Either there two or another larger breaker. usually or maybe just sometimts one AC is one circuit and the other ac on the other.50amp is to 50 amp circuits or legs with one common ground.
Two fifty amp circuits not two combined 50 amp circuits into 100 amps.

dougrainer

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Posted: 07/28/19 06:36am Link  |  Quote  |  Print  |  Notify Moderator

obiwancanoli wrote:

OK, here's a new development... I'd been trying the a/c a few times since my initial post, withalways the same results - no a/c... listening for the compressor(s) to come on, and it never did... So, today, I'm back in the same situation, only this time, I'm watching the display on the control unit, which for a Dometic unit, shows "E7" - an error code... so I look up the error code, and the manual states as follows: "Loss of 120 Vac power to all power module boards on the system. The system will shut down."

Now, I've checked the circuit breaker (20A), turned it off, then back on again...still no a/c... what else should I be checking?


E7 means there is NO 120 volts at the AC control board. Does NOT mean there is a problem with your Circuit Breaker. So, when this happens you do reset the AC circuit Breaker. Then if E7 remains you check the bottom of the 20 amp breaker to make sure power is present and the wire is connected and/or not burnt loose. IF OK, then you have to go to the upper AC control board and check the 120 wire connections at the Board housing. It is probably as simple as a loose 120 volt wire nut . Doug

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