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Old 06-17-2019, 03:04 AM   #1
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Model: Vegas 24.1
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AC readings. Any Experts in the house?

Having a cooling problem on my Vegas. Found a bad temperature sensor in the Evaporator and fixed that. Now I have some readings that don't seem right. Online some have indicated a possibility of a Plugged orifice/expansion valve.


Here are my readings with inside fan on high, engine @1500RPM, and window fan blowing across the condenser on the outside.



Ambient Air temp 94 degrees, cold air at outlet 53 degrees

(40 degree difference , OK I think)



Low side 12PSI, High side 275PSI

(this one seem odd, too low on Low side and a little too high on High side)


Any of you an AC tech and have any opinions?
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Old 06-17-2019, 02:34 PM   #2
lug
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THOR #11442
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Originally Posted by JoeDS View Post
Having a cooling problem on my Vegas. Found a bad temperature sensor in the Evaporator and fixed that. Now I have some readings that don't seem right. Online some have indicated a possibility of a Plugged orifice/expansion valve.


Here are my readings with inside fan on high, engine @1500RPM, and window fan blowing across the condenser on the outside.



Ambient Air temp 94 degrees, cold air at outlet 53 degrees

(40 degree difference , OK I think)



Low side 12PSI, High side 275PSI

(this one seem odd, too low on Low side and a little too high on High side)


Any of you an AC tech and have any opinions?
Low refrigerant will also yield the same results. Sloppy servicing can induce moisture, a slug of air, which can cause icing, plugged, on the expansion valve.
275 is high for 94F and at the low end for 95F. The low side should be 45 to 55 PSI at that temperature you stated. Before I would do anything I'd use another set of gauges to confirm that 12 PSI reading. You'll either confirm your original findings or identify a bad gauge(s).
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Old 06-17-2019, 03:23 PM   #3
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Thanks Lug,


I really appreciate your input. Sounds like my best next step is to evacuate the system and put it under a vacuum for several hours then recharge. Would that take care of any air or moisture?


JoeDS
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Old 06-17-2019, 04:47 PM   #4
lug
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Originally Posted by JoeDS View Post
Thanks Lug,


I really appreciate your input. Sounds like my best next step is to evacuate the system and put it under a vacuum for several hours then recharge. Would that take care of any air or moisture?


JoeDS
You nailed it! I personally do a vacuum leak check before I run the pump for at least a hour. No use running for hours only to find a leak under a vacuum.
Low pressure lowers the boiling point of water and if it is ice plugging the expansion valve that'll be quickly changed into a vapor which the vacuum pump can easily extract.
Be mindful of any oil that comes out so you can put the same amount back in.
At least you'll know exactly how much freon you really need to get proper operating pressures while finding the coldest evaporator temperature vice just filling it to whatever the sticker may say.
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Old 06-17-2019, 05:17 PM   #5
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Thanks Lug. I lost what seemed like a fairly good amount of oil when I removed the High pressure line. Have no way of knowing how much. It seemed like the shadier valve stuck open, so I'm going to replace it when I evacuate the system.
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Old 06-24-2019, 11:40 PM   #6
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Unhappy

Well it gets more interesting. The system charge was recovered, vacuumed down to -29 for several hours then recharged with 2.75 lbs with what I thought was the proper amount as seen on Evans webpage for the only listing of an RV with a Ford V10 engine. By the way Evans website is truly fantastic. Check it out: evanstempcon.com



Somewhat the same problem however with higher than normal pressure on the high side and lower than normal pressure on the low side. So with the weekend over I contacted Evans and Thor.


Evans folks were super helpful, but indicated they were in the dark since Thor has started taking over the filling of new systems at the factory. They contacted a Thor rep and were told the correct charge was 1.75 lbs.


Meanwhile I had also contacted Thor customer service, also very very helpful. However There I got back two different answers for two different reps. One was 2.25 ibs and then other was 2.75 ibs.


So now I have 3 different figures. 1.75, 2.25, and 2.75 lbs as the correct charge!! Quite a variance.


As an interesting side note Evans told me there was a label on the unit that was stamped with the correct charge. Sure nuff with the dash cover removed where you access the chasses battery. WAYYYYYY down at the bottom covered by the fresh air hose. With my cell phone set to take a picture with a voice command and a flashlight to illuminate it I got a picture. It was a blank box. The factory did not fill it in !!!


About the only thing I know to do not is recover the charge again and first try the lowest charge 1.75 ils to see if that works, then go to the next at 2.25 etc


Any other ideas?
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