Printable View
This is my first time repairing a domestic refrigerator. What should my operating pressures be?
I recovered and charged according to name plate. It runs at -10psig all the time and there is frost on the evap coil. It will freeze water in about 2 hour in the freezer and about a day in the fridge.
fridge and freezer are set to coldest, Gas is 134a.
Hi jake
I have not done many dom fridge freezers (only one but it worked) but my old boss did and he told me the method. Set stat at half way. Charge until there is a frost line on the suction pipe then release a little of the gas at a time (into a bottle) and wait patiently so as at the end of the cycle the frost line is about two inches inside the insulation at the bottom of the fridge. Then you may need to adjust the stat once you have a load in the fridge. This process took me a few days to get it right but it did work. There may be other methods which work better and no doubt an appliance tech would know better than me (imagine the bill for the customer if I fixed the gas leak) lol.:D
I can't remember the pressure but I know it was low.
Jake, Small refrigerant charge in domestics but if larger drier fitted then more R134a needed. Running a vacuum is not right, +1 to +2 psi at temperature is it.
Agree with mikeref +2 psi on low back pressure comps.
What repairs did you do to the machine which required re-gassing?
Brian,
The fridge was not keeping the food cold. So I leak checked it with nitrogen. Found no leak and it held 100psig for a day. Charged with 4.5oz using a digital postage scale.
I have been checking my amps on the compressor. 2 amp draw. Fridge says it runs at 7 amps.
Jakehabing, is that 2 amps on 110 or 240 volts? Also, 100 psi is not sufficient pressure for leak testing. Thinking about this... if there was refrigerant removed, then correct amount weighed in with origional drier, and fridge runs at -10 psi,.. me thinks capillary or drier may be restricting the refrigerant flow. Adding gas will increase high side pressure and force refrigerant through, giving false low side pressure readings. You said this was your first domestic repair? What do you normally work on?.. Mike.
Jake
The one I did I pumped up to 250 psi (could be a bit high for domestic) and even the my leak detectors and bubble test did not detect a leak but I knew it had one cause it had no gas to start with. I found a little oil around the joint on evap coil (cu - alum) so I taped a little plastic bag around it and sure enough there was the leak which I used some epoxy resin sort of stuff to fix and replaced drier with a slightly bigger one. That was 9 years ago and it still runs today. The current rating you might be looking at could be LRA Locked Rotor Amps which is 6 or 7 times higher than normal operating current. Like mikeref said - you could have a blockage and probably still have a leak there. So check for a small temp difference across the drier for the blockage but personally I would start all over again. Believe me I tried to fix three domestics with leaks before this one and ended up throwing them in the rubbish after too many wasted hours for a cheap fridge. Good luck and please keep us posted on any progress (good or bad).
If you see signs of a leak in the copper tubing, down the back/bottom near the compressor, then it may be worth repairing (depending if on suction line an how long run for if so - contanimation of the oil is a bitch).
Any domestic fridge with unknown leaks should never be bothered with, chuck it away. Too much hassle and probably has many other issues soon after.
As far as pressure, many I weighed in factory charge were always still in a vacuum, as many freezers on R134a and high TD will be. I normally added an extra 20-30 grams to get it just out of vacuum. Regassing them because of compressor change for example, I wouldn't re gas a leaking fridge as I said before.