Junction between capilary and evap stopping up after a few minutes of runtime.

[TwistedDiesel]

I'm kinda new to freezers, and systems running at such low temps/pressures, so I need a little help here.

I just bough a very nice (almost new) fridge/freezer that did not work. Found someone had worked on it previous and left the system open. I sealed the system, ran a vacuum for 30 mins, and charged it with R134a to 3 lbs low side and about 115 lbs high side at 70F ambient. The evap coils iced almost to the end, and everything looked just great for about 10 mins. Then the low side went to 20" vacuum, and the high side went to 170. I fiddled with it for a few hours and finally found that if I heat the junction between the capillary and the evap coils, it will hiss and start freezing immediately and the pressures go back to normal again for a few minutes.

My first assumption was moisture was freezing at that point and blocking the flow, so I put the system on a vacuum for about 6 hours and recharged and have the same problem. Is moisture still a possibility even after such a long vacuum or am I looking at another problem? Help!

[setrite]

Since the refrigerant circuit was exposed to ambient conditions for a long, you will need to pull a good vacuum of 500 microns, this could take more than 30 minutes. Your right that it is caused due to moisture in the system that freezes and blocks the capillary.

[monkey spanners]

Be a good to put fresh oil in the compressor too if possible.

[Rob White]

.

As all the other say.

Replace the dryer for a new one,
vac down to 500 microns (1/2 a torr) for a
good few hours. The level of the vac is much
more important than the length of time.
Then replace the refrigerant for new.

Rob

.

[TwistedDiesel]

Thanks, I ran a vacuum for 6 hours, my unit is old, but supposed to do 300 microns. I'm going to order a drier tomorrow, and maybe even install an automotive accumulator/drier in the suction line just for kicks and to see how it effects the system. (they call me crazy around here!) Thanks for the help, I didn't want to be cutting in to the cap tube for no reason!

I will be installing R290 after I get the system stabilized on 134a as I would like to try to lower power usage. I live in a solar powered home, and every little watt counts!

[monkey spanners]

change the oil in your pump too, once it gets wet it won't pull a good vac, had systems i've had to change pump oil four times to get dry