[BusNit]

That's how I sum up my air conditioning repair skills....

I soldered in the condenser coil today and nitrogen pressure tested it. Held without issues for an hour. I vacuumed it down to 370 microns. it held and balanced at a max of 1400 after an hour. charged it with about 30 oz of R22 and temps seem right on. Can you fellow A/C gurus see anything wrong with what I have going on? Reason I ask is that the unit label shows a max charge of 22oz at 24' of line-set. I have about 26-28' and the amperage is holding around 20.1amps with it maxed at what is in the pic. (This is indoor and outdoor consumption) Temps are about 109º out. Discharge air is 44º

[BusNit]

Edit: about 40 min later and amperage is at 18.3.

[Richard]

I think you have too much gas in it. High amperage, very high high side pressures, high low side pressures.

[BusNit]

I thought so too. Didn’t find the specs until after I had it running that said I have 6oz more than should be. It’s cruising at 16.7 now as the sun has set. I’m going to check to see if the coil is holding out with a sniffer. Need to open that outside unit up anyway since the fan is out of balance. I had to twist the case to get the torch in that tight confine and might have put something out of whack. Where do you think I need to be with the pressures?

[BusNit]

Well it’s scrap. Coil has another leak. No AC for this AZ bus. Marie was planning a trip next month but we will have to cancel.

[Richard]

Step back from the ledge………..

So you demonstrated that the unit works !

A lot less work in getting this one right, than installing roof units.

So find the leak, and decide what to do next. It wasn’t clear to me if you sourced a new coil or fixed the old one. Which was it?

And now you know how much to weigh in too. That almost 500 psi of head pressure didn’t do anything to help a leak. It really should have been less than 300.

Go easy on yourself, you are learning AC through experience, and there is a curve. I have been down a similar path, and there have been and still are some oh no’s. Given that the built in AC systems are a no man’s land, it pays to buy the equipment and learn to fix it on your own. A house tech won’t touch it, and an RV tech only replaces roof units.

I know you probably don’t want to hear this at this instant, but the one thing that I eventually purchased that took so much pressure off the AC work was a recovery unit. No puns intended. The ability to recover the refrigerant when something didn’t go right, made the work less stressful.

[BusNit]

Thanks Richard. I was using the green scale for R22 which was around 70psi low and 160psi high. I paid a shop $85 to fix the leak on the condenser itself. Looks like they soldered a couple of spots but another popped open. I think I will still cut the roof. Getting older and with that is the loss of time and patience.... I was going to invest in a recovery machine and tank, but I seldom do work on these. Used to install mini splits for friends and family. I stopped doing that. You know how it goes... "No good deed goes unpunished"

[Jack Houpe]

Just seen this thread and yes your low side is too high, evaporator temp at that pressure is 65 F, should be 35-40F. I would rather fix the old one or retrofit something else below than loose real-estate on the roof top, you will find the roof top units can be a pain in the rear. Remember you'll have water running off the roof all the time unless you can find a drain plus having to run electrical to it from the panel without messing up your beautiful inside. But if your going to d0 it Dometic makes a inverter roof unit.

https://www.dometic.com/en-sg/outdoor/sg...r-_-152020

I just built a freon recovery system, I had a good 120vac compressor so I silver soldiered the high and low sides closed and put line taps on them, then I took the valve out of an old propane bottle flushed it out with lacquer thinner and made a manifold. It worked wonderfully on the 24vdc AC system in our van, I had the compressor mounted under the van but decided to move it to inside for safety.

[BusNit]

That's interesting on the pressure. As soon as I got about 6oz in it, thats where the pressures remained up until I cut it off at 30oz. Unit calls for 22oz so I overshot a bit since my line set was greater than the 22' displayed on the unit. That said I am at a loss. I can't use this thing since it's hot out and it is becoming harder to be outside past 8am. If they made a mini split ducted that ran on 120v it might help but other than that, I think the Coleman mach 8 plus is the lowest profile unit available.

[ccjohnson]

Have you considered a trip to Miami? I had a guy in Phoenix work on one of my units for 4-4 days ordering and replacing parts. I had given him the manual from Dometic before he started. The tell should have been his reluctance to even glance at it. Tom McCloud had told me to check capacitors. After replacing condenser motor, compressor and drier, he noticed that the capacitor was shot. Still ended up making a trip to Miami to get it fixed because nobody seemed to be concerned about the glod of silver solder I saw drop inside the copper tubing when he was replacing the drier. Newell replace the compressor and then the drier and the short piece of tubing that had the solder blockage. Nitrogen would go past it easily, but you could not blow through it or evidently get refrigerant to pass by it easily. After that, unithas been working great! You do have my sympathies. We had to spend about 3 weeks in Gila Bend in July / Aug before we could make it to Miami with 2 good AC's and 1 that had been serviced from partially functional to inoperative. Ambient temps were 118 plus almost every day.