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Old 08-09-2014, 09:38 AM   #1
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New AC unit not cooling

Another AC not working thread. I have 2 new less than 1 year old Dometic Brisk II AC units on my Motor Home that have worked great. But at storage under cover running Oman 8000 generator. Good power on both legs verified on Progressive Industries 50amp EMS. Turn on AC and set to cool. Front AC cooling fine. Back AC fan working but no cold air. I turned everything off and waited and then turned back on same thing.

I got on top and removed the cover the fan is running and the compressor feels hot to the touch. There is not much else exposed on this new Brisk II unit under the cover.

I checked my PI EMS and with both AC's running I have 118 V on both line 1 and line 2. Line 1 with the front AC is showing 25Amp usage, Line 2 with the rear AC that is not cooling shows 10 to 11Amps used and stays at that figure.

These are units still under warranty I jst hate taking the time to leave it at the RV shop until they get a chance to look at it. Any thoughts
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Old 08-09-2014, 10:21 AM   #2
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New AC unit not cooling

The way I see it, if in fact the compressor is running, there are three possible reasons why the unit wont cool.

1. Refrigerant leaked out.

2. If the unit is a heat pump the reverser valve is stuck or is failed.

3. The compressor failed. (On the pump side)
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Old 08-09-2014, 10:38 AM   #3
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You didn't say whether the compressor was running or not. If the compressor was warm, then it was running at some time. IT may have a thermal cutoff and had stopped running. Check line 2 current with just the fan on. 10A sounds high for just a fan and low for compressor and fan, but until you check you won't know. If it is less with just the fan, then the compressor is running, but has no load which probably means a refrigerant leak.
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Old 08-09-2014, 11:09 AM   #4
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Originally Posted by adonh View Post
Another AC not working thread. I have 2 new less than 1 year old Dometic Brisk II AC units on my Motor Home that have worked great. But at storage under cover running Oman 8000 generator. Good power on both legs verified on Progressive Industries 50amp EMS. Turn on AC and set to cool. Front AC cooling fine. Back AC fan working but no cold air. I turned everything off and waited and then turned back on same thing.

I got on top and removed the cover the fan is running and the compressor feels hot to the touch. There is not much else exposed on this new Brisk II unit under the cover.

I checked my PI EMS and with both AC's running I have 118 V on both line 1 and line 2. Line 1 with the front AC is showing 25Amp usage, Line 2 with the rear AC that is not cooling shows 10 to 11Amps used and stays at that figure.

These are units still under warranty I jst hate taking the time to leave it at the RV shop until they get a chance to look at it. Any thoughts
Don,

The first check that I do for a unit that is not blowing cold is an amp draw test. From the figures hat you stated above, your compressor is running but there is nothing in the lines to compress.....YOU HAVE A REFRIGERANT LEAK.

If you want a more definitive test, place a clamp-on style amp meter on the back (sometimes blue) line going from the control board to the compressor, after it has been in 'cool' mode for at least 10 minutes.

When running properly, you should be reading near the 'RLA' amp listing on your data plate. The amperage will vary depending on the outside ambient temperature, but will generally be within 10% of the RLA. If it is unusually low, say 5-6 amps with an RLA of 12 amps, your unit has lost it's refrigerant, and you need to have the unit replaced, as it is not cost effective to repair the unit as it has no process valves on it, being hermetically sealed at the factory.

If these are Dometic units, they have a 2 year factory replacement warranty, and any factory authorized Dometic service center can handle the replacement for you.

Let me know if you have any other questions.

PS: your amperage figures are helpful, but not accurate, as a roof A?C of your type in full cool mode would draw a maximum of 13-14 amps at 95F ambient temperature. These numbers can again be found on the unit's data plate, and are a combination of the compressor RLA and the fan RLA, which are listed separately.
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Old 08-09-2014, 12:29 PM   #5
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Don,

The first check that I do for a unit that is not blowing cold is an amp draw test. From the figures hat you stated above, your compressor is running but there is nothing in the lines to compress.....YOU HAVE A REFRIGERANT LEAK.

If you want a more definitive test, place a clamp-on style amp meter on the back (sometimes blue) line going from the control board to the compressor, after it has been in 'cool' mode for at least 10 minutes.

When running properly, you should be reading near the 'RLA' amp listing on your data plate. The amperage will vary depending on the outside ambient temperature, but will generally be within 10% of the RLA. If it is unusually low, say 5-6 amps with an RLA of 12 amps, your unit has lost it's refrigerant, and you need to have the unit replaced, as it is not cost effective to repair the unit as it has no process valves on it, being hermetically sealed at the factory.

If these are Dometic units, they have a 2 year factory replacement warranty, and any factory authorized Dometic service center can handle the replacement for you.

Let me know if you have any other questions.

PS: your amperage figures are helpful, but not accurate, as a roof A?C of your type in full cool mode would draw a maximum of 13-14 amps at 95F ambient temperature. These numbers can again be found on the unit's data plate, and are a combination of the compressor RLA and the fan RLA, which are listed separately.
Thanks Lew and everyone. I will call Bob Jones RV here in Houston on Monday, they did the install, and let them check it out.
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Old 08-21-2014, 09:16 AM   #6
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Thanks Lew and everyone. I will call Bob Jones RV here in Houston on Monday, they did the install, and let them check it out.
Took the coach to Bob Jones yesterday and they called this morning, bad compressor. Dometic approved a complete new unit under warranty. It should arrive tomorrow.
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Old 08-21-2014, 08:30 PM   #7
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Call me old fashioned, but disposable products bug me.

Glad they got you going!
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Old 08-27-2014, 08:32 AM   #8
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Someone posted a question in my Thanks section, Did I think running the AC on generator power had in effect on the life of the compressor?

I would not think so.
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