finding an incredibly small leak!

[The MG Pony]

I got a fridge in with a fried thermistat, so I figured I would switch to a low side switch to control evap, so I put the new switch in and vac down for an hour, then stop to watch for rise, it whent from 27" to 24" in a matter of a couple hours, so I figure it was the oil gassing off so I let it sit over night.

In the morning I vac down for half an hour to 27" (My pump is gimped ISo it can only go to 27) and let it sit, pressur seems to hold so I vac it down for another half hour and leave it over night, it is Now at 24" of vac, I tried soap and bubble when it was pressurized and didn't see any thing!

I am possitive it is the evap, but how can I test for certain it is a leak with out cuting it off and pressur testing @ 300? I would like to avoid if at all possibly cuting open the system further.

forgot to add it heald 70psi for one night as well.

[Brian_UK]

Don't normally work on fridges so my knowledge is limited, however my two cents worth....

70psi doesn't seem to be a very high pressure test figure.

Vacuum down to 24" to 27" is also not very low. Inches are no good for vacuum readings, Torr or microns are preferred.

How confident are you of the installation of your pressure switch, so new joints there that weren't on the original?

Are your manifold gauges/hoses/seals leaking, not unknown.

[The MG Pony]

brand new seals on hoses and the hose is brand new, the pressure switch won't be leaking for the next 20 years I was very thorough on pipe prep and used high quality 15% Silfoss. this was happening be for I added the switch, I figured there my be a leak which lead to the demise of the thermostat that was in it, due to reduced load handling.

BTY I charged 70psi with R-290 in hopes some oil would seep out where the leak was, but didn't help.

[Brian_UK]

Drat, couldn't even get a small flame going either I bet....

[The MG Pony]

Not even a wuff <_< This sucker is hiding good. I'm going to just cut it out and pressurize it to 300 PSI immersed in soapy water, see where the bubble form on the surface. I'm not seeing many other options.

[Brian_UK]

Is the fridge cabinet air-tight when closed?

Would it be possible to put a leak sniffer inside the cabinet with some 290 in the system to see if anything leaks in that area.

If it stays clear of alarm then it pushes you towards the outside of the unit.

[The MG Pony]

it is an extremely simple upright fridge. R-22 condenser on top and at the very bottom a small evap. The Alu fins show strong signs of galvanic corrosion, I gave the cabinet a good sniff and didn't detect the propane. I a know the schrader needs its core replaced on the top unit, while I got the evap off I'll do a vac of the condensing unit and see if it rises like befor.

[The MG Pony]

Update, just cut it out and There are deep pits etched into the copper Evap is now a tight sieve rather then a evap!

[Brian_UK]

So you just need a flute player to stand there with his hands out

[The MG Pony]

lol, well just for the fun of it I put in a tube of water and a steady stream of verry tiny bubbles came up through out it @ 400psi that leaves no question about it. Had to site a second or so for them to start to pop up.

I just tried google to get some compressor specs and got no where <_< The number is: ARE4-0025-IAA-200

Does any one have general info on that compressor? Need to figure it out to see what I can do as far as the evap goes! Looks like it is set up as HST.

[Sledge]

I am now doing what you did, every time I leak check. I pressurize the system to 300psi and soap everything.

I find it doesnt really take that long compared to the time you waste fiddling around trying to avoid doing it.

Since I started this, I havent had a single call back.

[The MG Pony]

ya the soap pressure test sure does highlight em. I really didn't want to and was hoping it was an oil gassing off but that kind of rise during a vac can only be a leak. They payed fifty bucks for the fridge at an auction so as the saying goes: Ya get what ya pay for, then again the box is worth more then a few bucks so in the long run worth repairing!

Any one got info on the compressor? would be a great help as I may just put in a TXV evap.

[Brian_UK]

The compressor seems to match some of the Copeland (Emmerson) numbers but I haven't found yours yet.

Just as an indicator.....of some of the part numbers...

http://www.emersonclimatecontractor....it_sheet_8.pdf