I was away and got a text that the a/c was no longer working.I came home to the RV about an hour or more later. The two interior fan speeds work. When i switched to a/c, I think I heard the compressor come on. So I climbed up, and pulled the wires off the capacitor. Discharged it. Measured like 5-6 Mohms... and climbing i think i remember.Then I measured the compressor...C-S 5.5 ohmsC-R 1.3 ohmsS-R 6.2 ohmsBut now I remember, the black wire from the compressor was still connected to the board. Was the black the common? Maybe it made no difference if it was just grounded?So I put it back together, and it seemed to run for a few hours, but It wasn’t making cold really well. So I was thinking, maybe it needs coolant. It has a port installed and was charged at the beginning of the summer.Then, a little while ago, it kind of cycled off, but in a weird way that drew my attention. Maybe it made a different sound than normal. Nothing dramatic as far as a sound that I can report here. But i turned thermostat knob to very warm to just let fan run for awhile. Then after about 10 min, turned it cooler and cooler, but nothing happened. I didn’t hear any attempt at compressor turn on. Then I left thermostat at very cold setting and went to fan only for awhile. Came back to a/c .. nothing.What should I do now?

Ooh... after letting it sit for 30 min on fan only, then going a/c low, i hear the compressor come on.

But, it seems to not really make cold.What should I do?

So, on the lable on the compressor, it says “thermally protected”Being in Quartzsite, Az... yes, its pretty thermal. But, its a dry thermal.Then, perusing the internet, I read this...“Low refrigerant flow will also cause refrigerant-cooled compressors to overheat.”Is all this adding up to ... I need to recharge the coolant?

I lived there 13 years... the last 13 years of my hvacr career, and it's anything but dry during monsoon! You know what that heat does to you, now imagine being a condensing unit trying to expel heat in 110+ ambient! I always fix the duct and plenum problems on my rvs and cut in larger ceiling diffusers and after that, regular thorough cleanings, especially the cond. coil, keeps mine working great, even after 12+ years. Ignoring the cond. coil cleanings drives the head pressure up and that takes it's toll on the electrical components, fast, not to mention the compressor reduced capacity. The heat there is ridiculous and you have to keep coils clean and the electrical in tip-top shape or it's curtains for your little ac. You MUST keep up on the ac maintenance in the h@ll you're in! You Tube is your friend if you don't know what to do. Craig

If someone put a charging port on it in the past, sounds to me like it's time for a new A/C.

A/C help needed. Coleman mach 8 .. Quartzsite | Good Sam Community

groundhogy
Explorer
Aug 31, 2020
This installer had one guy at the top. One guy at the bottom of the ladder.
Extension ladder tilted onto the RV.
Rope with hook (onto some feature of the A/C that i couldn’t see.).
Slide A/C down ladder to ground person.
dougrainer
Nomad
Aug 30, 2020
deltabravo wrote:
The hardest part of replacing the A/C is getting the new one up on the roof, and getting the old one off the roof.

I did it a few years ago when I switched to a Mach 8 heat pump

Yes, that is a great way to do that. But, try that with a Metal Airstream:B You can do it, but be very careful. This is what our shop uses(not this brand), and have for 35 years. The one we use is about $1400, but is easily broken done at center to load in a pick up truck for mobile use. IF I decided to do mobile RV service, this is one tool I would have. It would pay for itself in a few months. Doug

https://images.app.goo.gl/N2JiaLYYSQTwQ2fs7
deltabravo
Nomad
Aug 30, 2020
The hardest part of replacing the A/C is getting the new one up on the roof, and getting the old one off the roof.

I did it a few years ago when I switched to a Mach 8 heat pump
dougrainer
Nomad
Aug 29, 2020
groundhogy wrote:
Yes, the mach 15 fan is quiet , but also the compressor sound is quiet.
You listen for the compressor sound when you want to see if it’s actually on.

The tech was not approving of dometic penguins (their low profile offering?). He said he has a small pile of them at his home base that are broken and he said like 3 years old.

The newer style Penguins that had 410, Airstream had a problem caused by installers at Airstream. They were bolted from the top down and when they manhandled the Penguins on top to mount(they had to remove the top shrouds), they were pushing the Copper lines against each other and the normal vibration of running caused the line to rupture and leak coolant. Dometic replaced hundreds if not thousands of those Penguins on Airstreams for a few years until Dometic found out what was happening. Dometic then installed rubber bushings around the copper lines at areas that could be pushed to prevent this. Also, the original Penguins that had 410, the compressors run at higher PSI due to 410 and the first compressors had a high failure rate, which Dometic replaced the design of the compressor's once they realized that problem. The Penguins built in the past 2 or 3 years, are just as reliable as ever. Doug

PS, the original Mach 15 also had a high failure rate due to the design of the separate Condenser fan system. The motor mount bolts would break off and the fan would fall over and sometimes shear the regular condenser. This is the reason they redesigned that system and it is quieter now.
groundhogy
Explorer
Aug 29, 2020
Yes, the mach 15 fan is quiet , but also the compressor sound is quiet.
You listen for the compressor sound when you want to see if it’s actually on.

The tech was not approving of dometic penguins (their low profile offering?). He said he has a small pile of them at his home base that are broken and he said like 3 years old.
dougrainer
Nomad
Aug 29, 2020
groundhogy wrote:
The new a/c is a Coleman mach 15.
It is called a 15kbtu, but i think i saw on a lable it listed as a 14.5k.
The last a/c was a 13.5k mach 8 low profile.
I can report these observations.

Cooling: Not a dramatic difference although the mach 15 seems better. Mach 15 a simpler design. The Mach 8 literature says it is a more efficient design i think because they separatet air moving with 2 fans. Allows condenser fan to run full anytime its desired? So maybe at 13.5k and more efficient, it approaches a standard a/c at 14.5k? Idk.

Compressor quietness: When the two techs came inside to do the first turn-on, they thought the mach 15 wasn’t working. Thats how quiet the compressor is. I assume compressor vibration is low also. The mach 8 compessor was louder and wiggled alot. I think this caused/assisted the eventual copper tube rupture.

Note that the above may not hold for all purchases for all time as the mfr may use several different compressor brands on their factory line.

Your new model the Condenser fan runs ANYTIME the compressor runs. Yes, it is quiet. Funny thing is, the original 15, the Condenser fan system sounded like a jet engine. RVP redesigned the fan blade and Condenser motor system to be quiet like you have now. Doug

PS, you must have a OLD Airstream to have a factory installed RVP AC unit. A/S has used Dometic for almost 20 years now.
groundhogy
Explorer
Aug 29, 2020
The new a/c is a Coleman mach 15.
It is called a 15kbtu, but i think i saw on a lable it listed as a 14.5k.
The last a/c was a 13.5k mach 8 low profile.
I can report these observations.

Cooling: Not a dramatic difference although the mach 15 seems better. Mach 15 a simpler design. The Mach 8 literature says it is a more efficient design i think because they separatet air moving with 2 fans. Allows condenser fan to run full anytime its desired? So maybe at 13.5k and more efficient, it approaches a standard a/c at 14.5k? Idk.

Compressor quietness: When the two techs came inside to do the first turn-on, they thought the mach 15 wasn’t working. Thats how quiet the compressor is. I assume compressor vibration is low also. The mach 8 compessor was louder and wiggled alot. I think this caused/assisted the eventual copper tube rupture.

Note that the above may not hold for all purchases for all time as the mfr may use several different compressor brands on their factory line.
sayoung
Explorer
Aug 27, 2020
garyemunson wrote:
If someone put a charging port on it in the past, sounds to me like it's time for a new A/C.

If OP had it charged then it's got a hole somewhere. Get that fixed or replace the unit. Those compressors need the proper amount of returning gas on the suction line to cool it.
time2roll
Nomad
Aug 27, 2020
I would have a new high efficiency unit installed. This thing is done.
groundhogy
Explorer
Aug 27, 2020
Bad Design:
Having that long soft copper tube hanging out there and wiggling like that IS a bad design.
I am not a mechanical engineer and it totally captured my attention.
On the other hand, I’m not sure how the engineer would cheaply address that. Maybe put lead tape on the compressor to limit wiggle? The compressor mounts on rubber.
Its the compressor people that should be reducing the wiggle on their product. Tecumseh is mfr.

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A/C help needed. Coleman mach 8 .. Quartzsite

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