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Old 06-21-2020, 04:04 PM   #1
mtlakejim
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Adding freon

Our front roof A/C will cool for about 3minutes then starts blowing hot air. It's 106F here by the way.

A. Is that a sign of low Freon?
B Can you add Freon to an RV roof A/C?
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Old 06-21-2020, 04:29 PM   #2
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I don’t think you can add Freon. I suspect sorry to say get your pocketbook out.
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Old 06-21-2020, 05:18 PM   #3
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Old 06-21-2020, 05:20 PM   #4
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Unless you see a "high pressure" and a "low pressure" port, forget about adding "Freon". Normally, you recharge using the low pressure port. At minimum, you need a hose and a gauge.

Info...Freon (r12) has not been used in years and you cant get it in the states. Its probably r134 or something newer. I guess over time the term Freon has now become generic for refrigerant like Kleenex is for tissues. Not trying to be a smarta--.
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Old 06-21-2020, 05:47 PM   #5
mtlakejim
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M.O.C. #20693
well this is just weird. It seems to be working fine now.
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Old 06-21-2020, 05:48 PM   #6
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Don't remember on which site I read the post, but someone posted that they had a really good AC Tech look at their AC and ended up cutting the compressor line and installing a recharge port. Recharged and folks were really happy as the AC worked better than when it was new.
So guess if you could find an "Old School" AC Tech you might have a chance.
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Old 06-21-2020, 06:00 PM   #7
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If you can't find someone like that it's a sealed system and so it's trash.
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Old 06-28-2020, 08:09 PM   #8
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They make a clamp on port for the low side to add Freon, my ac guy used one on our park model and said that’s what I need for our rv if it gives us problems
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Old 06-28-2020, 09:19 PM   #9
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Quote:
Originally Posted by mtlakejim View Post
well this is just weird. It seems to be working fine now.
Evaporator freezeup. Humidity.
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Old 06-29-2020, 05:25 AM   #10
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Originally Posted by prndl View Post
Evaporator freezeup. Humidity.
Humidity in New Mexico?
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Old 06-29-2020, 06:43 AM   #11
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Originally Posted by jeffba View Post
Humidity in New Mexico?
It's not what's outside, it's what's being recirculated over the evaporator from inside.
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Old 06-29-2020, 06:48 AM   #12
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That could be the problem. In NM I have to turn my livingroom unit fan to high once it starts continuously running or it will freeze up. Yesterday the temp here in Kansas was 98 and the dew point 74 but it didn't freeze up and was set on auto all day. Doesn't seem to make sense, but it is what it is.
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Old 07-05-2020, 08:33 PM   #13
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Quote:
Originally Posted by mtlakejim View Post
Our front roof A/C will cool for about 3minutes then starts blowing hot air. It's 106F here by the way.

A. Is that a sign of low Freon?
B Can you add Freon to an RV roof A/C?
Good possibility the baffle in the unit is loose. That will allow it to blow hot then cold. Easy fix. Reattach the baffle.
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Old 07-06-2020, 07:42 AM   #14
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If you freeze up and it's hot outside, you either have a leak or there is not enough air blowing over the evaporator (cooling coil). If you think It's low on refrigerant, Most likely there is a leak. So that must be located and repaired then refrigerant added. Mine froze up but it was mainly due to a to low outside temperature, happened at night. At first I though it was a low charge, checked with the dealer, and they said that their techs don't even work on the units, they just replace the whole roof top unit. Guess they are made pretty cheaply. In any case, unless you have experience in a/c repair, I would call a qualified technician.
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Old 07-06-2020, 10:14 AM   #15
denhammkc
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Mine froze up 2 months after I got it. There is a temperature probe that is inserted in the coils to regulate the cycle of the cooling to prevent freezing, mine fell out and see attached. With the whisper quiet you have to get on roof and open it up to fix.
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File Type: jpg 2016 MONTY(1069).jpg (182.1 KB, 4 views)
File Type: jpg 2016 MONTY(1068).jpg (172.6 KB, 6 views)
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Old 07-06-2020, 02:53 PM   #16
Mroe
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With R-22 (which they are phasing out now) even with an evaporator pressure at 60 PSI, that's a coil temp of 34 degrees F. Which should not freeze up the coil, unless no air flow or extremely low ambient temperature. Or as in someone's case, had a sensor come off the coil and it continued to run in a low ambient air temp. Lastly, a leak and a low evaporator pressure/temperature, it will freeze up.
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Old 07-06-2020, 06:03 PM   #17
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Ok so here is the thing after a few days. It doesn't happen every day but on some days the unit will suddenly start to blow hot at about 2pm (peak heat of the day). You can turn it off for about 30 minutes and it will blow cold again and work fine after that.....
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Old 07-06-2020, 07:38 PM   #18
jchw
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When I lived in Kansas and went out with my Monty, I found both A/Cs would struggle if the wind is blowing in towards the coils (blowing from the "south end" of the 5'ver). Second, when I had an A/C tech come out one time to check them out, he did find LO/HI pressure ports and "topped off" the units. Third, the A/C tech told me to not expect more than a 20 degree difference between indoors vs. outdoors. Fourthly, I have a surge suppressor (Technology Research 50-amp protector) that I can monitor the quality of power, and amps being pulled on each leg. Knowing if there is an under voltage condition on one leg, I can assess whether or not the A/Cs are being "underfed". Good luck!
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Old 07-06-2020, 08:34 PM   #19
Mroe
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The tech is correct, a/c units at best will do what they call a 20 degree split. So if you have 80 degree air going in, the best you'll get out is 60. But you sure could have a low voltage issue, not sure how that will affect an a/c unit though. But...... if the tech had to add more refrigerant, it was either not charged properly from the factory, or you have a slow leak.
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Old 07-07-2020, 04:17 AM   #20
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I was wondering if this was posted before, we were having moisture problems with AC dripping water. I have worked on and installed AC units for years. I know if after running for hours you're getting water forming you have an outside air leak allowing outside air in. I took a couple of pieces of cardboard and blocked off the return air vents in steps(2010 3000rk) and guess what, not only did that fix my water dripping but our upstairs bedroom is now cooler than it ever been. I don't know if this was posted before, only my 2nd year on Montana's chat site, but this week we are going to be in the 90s all week,( SW PA.) and thought this might help someone else. Thanks for listening. Doc C.
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