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mike brez

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Posted: 06/19/19 08:27am Link  |  Quote  |  Print  |  Notify Moderator

Ok both my rooftops are not working. Dometic Duro Therms.
Took covers off and installed peircing service valves. Both had no freon. Both had pin holes in capillary tube in same place apparently rubbing issue. Cut sheet metal to access. Put a drop of braze on one and cut one out and sleeved with a peice of 1/4 inch tube and brazed. Pulled a vacuum on both and filled both with 24.5 oz of r22.
Wasn't very warm but shot the rear plastic ac grate with ir gun 67* fired up generator turned rest ac an feels cool 15 min shot plastic ac grate again in same spot 48*
Shut down rear and started front. Fan comes on but compressor keeps on trying to start every minute or so and cuts out. Removed wires from compressor and all have continuity. Switched all capacitors and compressor over load switch from working rear to front and no change. I guess compressor is locked up. Was thinking of trying a hard start kit but not sure it would work. Was thinking about trying to find a compressor but a quick search showed nothing. Gotta hop back on roof and get numbers off it. Here's a few pics.

[image]

[image]

[image]

[image]

* This post was edited 06/19/19 08:35am by mike brez *


1998 36 foot Country Coach Magna #5499 Single slide
Gillig chassis with a series 40
02 Ford F250 7.3 with a few mods
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newman fulltimer

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Posted: 06/19/19 08:41am Link  |  Quote  |  Print  |  Notify Moderator

Those ac units don't run on r22 is the first problem

* This post was edited 06/19/19 09:48am by newman fulltimer *

dougrainer

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Posted: 06/19/19 08:57am Link  |  Quote  |  Print  |  Notify Moderator

If you are talking 1998, then Freon 22 is the Freon to use. BUT, most units use only 16 to 20 ozs of Freon. HOW did you determine the correct Freon fill capacity? There are only 2 ways to fill a Roof RV AC
1. Dial a Charge
2. Temp corrected amp draw AT the compressor
Regardless, your Compressor is not caused by your fill. You have a bad compressor. YES(or NO) you will not find a replacement Compressor for a RV Roof AC unit. They have not made replacement compressors for more than 30 years as it was cheaper to replace the upper unit complete than pay to replace the compressor. Doug

PS, since you are handy brazing the lines, LEAVING the Line taps on is foolish. You only install Line Taps to safely(EPA) drain any possible Freon still in the system and then braze the Line Tap pin holes and braze in standard copper Schrader valves. Line Taps WILL LEAK. Eventually.

mike brez

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Posted: 06/19/19 08:58am Link  |  Quote  |  Print  |  Notify Moderator

newman fulltimer wrote:

Those av units don't run on r22 is the first problem



Hmmm pic of compressor and my owners manual were I found how much freon it takes

[image]

[image]

mike brez

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Posted: 06/19/19 09:09am Link  |  Quote  |  Print  |  Notify Moderator

dougrainer wrote:

If you are talking 1998, then Freon 22 is the Freon to use. BUT, most units use only 16 to 20 ozs of Freon. HOW did you determine the correct Freon fill capacity? There are only 2 ways to fill a Roof RV AC
1. Dial a Charge
2. Temp corrected amp draw AT the compressor
Regardless, your Compressor is not caused by your fill. You have a bad compressor. YES(or NO) you will not find a replacement Compressor for a RV Roof AC unit. They have not made replacement compressors for more than 30 years as it was cheaper to replace the upper unit complete than pay to replace the compressor. Doug

PS, since you are handy brazing the lines, LEAVING the Line taps on is foolish. You only install Line Taps to safely(EPA) drain any possible Freon still in the system and then braze the Line Tap pin holes and braze in standard copper Schrader valves. Line Taps WILL LEAK. Eventually.


I agree 100% on the line tap. I weighed the freon on a scale.
I may just replace both as's. You have seen and worked on more of ac's than anyone on the forum. What brand would you recommend for replacement.

RLS7201

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Posted: 06/19/19 09:12am Link  |  Quote  |  Print  |  Notify Moderator

Mike, you should have ask the experts first, then you could have really screwed things up......GRIN. GOOD JOB.
I bet you have the same card in you billfold that I do.
It says, "your name" has been certified as UNIVERSAL technician as required by 40 CFR Part 82, Sub Part F.

Richard


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they would eventually, find me attractive.

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Gundog

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Posted: 06/19/19 09:15am Link  |  Quote  |  Print  |  Notify Moderator

You might find the compressor is also made for other applications and find a replacement that way or maybe not good luck. Good job on fixing one of them.


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mike brez

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Posted: 06/19/19 09:18am Link  |  Quote  |  Print  |  Notify Moderator

RLS7201 wrote:

Mike, you should have ask the experts first, then you could have really screwed things up......GRIN. GOOD JOB.
I bet you have the same card in you billfold that I do.
It says, "your name" has been certified as UNIVERSAL technician as required by 40 CFR Part 82, Sub Part F.

Richard


I have a roofer license it covers everything.

dougrainer

Carrolton, Texas

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Posted: 06/19/19 09:50am Link  |  Quote  |  Print  |  Notify Moderator

mike brez wrote:

dougrainer wrote:

If you are talking 1998, then Freon 22 is the Freon to use. BUT, most units use only 16 to 20 ozs of Freon. HOW did you determine the correct Freon fill capacity? There are only 2 ways to fill a Roof RV AC
1. Dial a Charge
2. Temp corrected amp draw AT the compressor
Regardless, your Compressor is not caused by your fill. You have a bad compressor. YES(or NO) you will not find a replacement Compressor for a RV Roof AC unit. They have not made replacement compressors for more than 30 years as it was cheaper to replace the upper unit complete than pay to replace the compressor. Doug

PS, since you are handy brazing the lines, LEAVING the Line taps on is foolish. You only install Line Taps to safely(EPA) drain any possible Freon still in the system and then braze the Line Tap pin holes and braze in standard copper Schrader valves. Line Taps WILL LEAK. Eventually.


I agree 100% on the line tap. I weighed the freon on a scale.
I may just replace both as's. You have seen and worked on more of ac's than anyone on the forum. What brand would you recommend for replacement.


IMO, You only have 2 choices. RVP(Coleman) and Dometic. Odds are, your old tstat system may not work with the NEW style Dometics. Your 1998 was right on the change over from the LED wall tstat system to the original 4 button wall LCD CCC Dometic control system. IF you have the 4 button Dometic CCC system with the telephone type COM cable, I would replace both roof top units and purchase a 10 button Dometic CCC wall tstat. It is plug and play. I would go with 15k Penguin units as they have the 10 button control boards already installed on the Unit. Doug

Matt_Colie

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Posted: 06/19/19 11:19am Link  |  Quote  |  Print  |  Notify Moderator

Mike,

Nice Silphos job. I have to wonder why you didn't braze in the access fitting.

Cheap trick from an old reefer mechanic (that is who taught me), get power on the compressor give it a shot with a soft faced hammer. It may just start, and you sure have nothing to loose by trying. It worked the once he showed me and twice more for me.

He told me that this may work because when a pump (compressor) is run charge short, something happens to the lube oil.

Good Luck

Matt


Matt & Mary Colie
A sailor, his bride and their black dogs going to see some dry places that have Geocaches in a coach made the year we married.


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