stan
5 Cubic Foot
Posts: 98
|
Post by stan on Jan 16, 2018 16:48:46 GMT
Good to know about the 417c. Just in case. back to the possible leak.. If the leak is so tiny that it's good for 5years, I don't mind having it recharged.. Provided they'll do it. When I called to get the appt to have him come out, they said that if there was a leak, it could not be repaired?? "It's probably so small we won't find the leak again, the dye test is to satisfy our records for EPA" If there is a leak in the evaporator, how is it normally repaired?
|
|
|
Post by Travis on Jan 16, 2018 17:17:51 GMT
Stan,
It depends where the leak is. The evaporator is stainless steel. I’m not sure anyone would try to repair it.
If they won’t charge it, you may have to find another technician or make arrangements with coldspaces to get another unit. FEA’s don’t weigh much thankfully.
If crated, and dropped off and picked up at the freight terminal, you’re looking at 150-200 to ship a unit probably. Then you’d have to have it painted.
|
|
|
Post by ckfan on Jan 16, 2018 18:08:10 GMT
Someone here mentioned that there is an epoxy that is used to repair evaporators. I think it is made by Supco.
|
|
|
Post by blackhorse on Jan 16, 2018 18:47:46 GMT
Also 134a is not compatible with the mineral oil used in your FEA R12 system. 134a takes POE oil, oil return and proper lubrication could be a problem substituting 134a for R12. That's very good to know... I guess the R12 in a car is different than in a Monitor top?? Or at least the oil is?? Well yes and no. *Waffles* Usually when you replace R12 in a car with 134a, you use 1 can of conversion oil (per 4 lbs or as per directions), and that contains additives to help with oil return, and the rest straight 134a. And "monitor top" usually means SO2; the SO2 units were made with special designs to return oil even if the refrigerant doesn't mix with the oil (SO2 is not miscible with mineral oil), so the oil return works fine with 134a which is also not miscible with mineral oil. The FEA units were R12 capillary units, which depend on the oil mixing with the refrigerant to return it to the compressor (as do all "Freon"-type systems), so the 134a not mixing with mineral oil would not return oil properly. Also: Automotive systems are belt drive. Hermetic systems have the electric motor inside with the refrigerant. I have serious reservations with automotive additives being added to an electric motor. We have no idea what effect the sealing or mixing additives would have on motor insulation, if they are conductive (short out the windings), might plug capillaries, or ?
|
|
|
Post by blackhorse on Jan 16, 2018 18:59:17 GMT
Someone here mentioned that there is an epoxy that is used to repair evaporators. I think it is made by Supco. NO-OOOOoooo! Tried and failed. Several brands and applications. Epoxy mixes and hot-melt sticks. It only works temporarily (long enough to sell it to some sucker), the oil eventually softens it and it leaks over again. You can solder them, but it's damn tricky, takes solder with silver content 50% or higher, the special "black" flux, and cleaning to NASA clean room standards. I did it to the double-evaporator CK3 unit for my 2-door cabinet. If you do find that the evaporator leaks, and has to be addressed, you would be better off finding another evaporator, removing it with several inches of copper tubing still attached, and replacing it, with the soldering confined to the copper tubing. I've also done this with modern aluminum evaporators with stupid machete-related defrosting accidents.
|
|
|
Post by timeswelding on Jan 17, 2018 1:16:37 GMT
The evap could be TIG welded without too much trouble. Just purge with argon or nitrogen to keep it from oxidizing inside.
|
|
|
Post by blackhorse on Jan 17, 2018 5:09:22 GMT
The evap could be TIG welded without too much trouble. Just purge with argon or nitrogen to keep it from oxidizing inside. Don't know. That's mighty thin metal to TIG weld. I've tried it with aluminum evaporators. Then into the recycle bin....
|
|
|
Post by solarmike on Jan 17, 2018 14:19:45 GMT
The evap could be TIG welded without too much trouble. Just purge with argon or nitrogen to keep it from oxidizing inside. Don't know. That's mighty thin metal to TIG weld. I've tried it with aluminum evaporators. Then into the recycle bin.... I agree, I think you would blow a hole right through it...
|
|
|
Post by don on Jan 17, 2018 15:09:20 GMT
I bought a pristine FEA unit last summer that looked like it had very little use. I bought it in a building that had no electricity so I could not test run it. When I brought it home and ran it it had an evaporator that was only partly frosted which indicated a leak. I have two electronic leak detectors and neither could pick up a leak which meant it was under 1/2 ounce a year. I no longer have access to nitrogen (retired) to pressurize the system to make the leak easier to find so on a hunch I enclosed the entrance tube and leaving tube to the evaporator in plastic/duct tape and let it sit overnite. The next day when I slit the plastic with a knife and inserted the probe of my leak detector into the plastic it was obvious that there was an accumulation of R-12 inside of the plastic enclosure of the tube entering the evaporator coming from the cap tube. There was no oil at the leak site so I am sure dye would not appear either. A thick leak finding bubbles solution left on the joint for hours confirmed the leak with tiny tiny almost microscopic bubbles. I am sure it left the factory in 1946 with this leak.
Stainless steel is repairable with silver brazing solder and after recovering the charge it was easily repaired with flux/silver brazing solder. I added a modern access fitting and filter drier to the system and charged it with the last of my r-12. When it warms up here in Minnesota I will add a picture of the filter drier location and place it in a post in the FEA section.
|
|
|
Post by timeswelding on Jan 17, 2018 22:23:47 GMT
Don't know. That's mighty thin metal to TIG weld. I've tried it with aluminum evaporators. Then into the recycle bin.... I agree, I think you would blow a hole right through it... Not necessarily. Thinner material just takes a bit of practice. I just took a picture if a couple Mountain Dew cans that I welded together, but the forum is out of space and I can't upload. Bummer.
|
|
stan
5 Cubic Foot
Posts: 98
|
Post by stan on Jan 17, 2018 23:04:01 GMT
So the technicnition has been here and left. Heres a description of what he did. Pumped 50 psi with nitrogen. Found small leak at suction joint to evap. Remove top of box, and used torch to fix leak. Thought he have to solder but it was enough to seal. Rechecked, good (Success) Then.. Evacuate, won't go below 460 micron. Charged with 409a. Electronic picked up trace in upper sealed deck between condenser and evaporator. He got a even frost, but it quickly started to defrost. He said the only way to fix is to take top back to shop, and disassemble re do with copper. He suspects that there a internal rust hole. Dosnt know what material was used for insulation that could have held moister next to line. He was not able to take with him as his truck was full, and wanted to set it up for safe transport. So I need to think about this, as this service was expensive. And probably will be to have him cart it back to the shop, repair and come back. I saw a working CK unit on CL a hour and a have away for 400.00? Looks good, but..
|
|
|
Post by Travis on Jan 18, 2018 1:59:14 GMT
It's something like a fiberglass insulation. The tubing in there would be copper, or it was on the one I opened.
|
|
stan
5 Cubic Foot
Posts: 98
|
Post by stan on Jan 18, 2018 3:24:01 GMT
Hi Travis. I really had my hopes up when he decided to lift off the top and get after the leak. After he used the tourch and rechecked with good result, I thought my troubles were over. But..the electronic gizmo picked up a leak. He said it couldn't be anywhere else except somewhere between the sealed deck. He seemed to know his business, and mentioned that he'd recently worked on a S02 unit, recharging it with S02 (still used in the wine idustry) How labor intensive is opening this?
|
|
|
Post by blackhorse on Jan 18, 2018 13:08:30 GMT
Clearly the leak is much larger now, if it leaks out in a matter of minutes you should even be able to hear it.
I would suspect that simply heating the joint with a torch wouldn't seal it, there would be oxide in the cracked joint; it would need to be cleaned of all oxide and re-soldered with silver.
Keep in mind that unless he got a new electronic leak unit, the one that detects R12 won't necessarily indicate anything with the new refrigerants, it could be blowing right past it and not show a thing.
|
|
|
Post by timeswelding on Jan 18, 2018 13:15:07 GMT
I would suspect that simply heating the joint with a torch wouldn't seal it, there would be oxide in the cracked joint; it would need to be cleaned of all oxide and re-soldered with silver. Amen to that. Simply heating a joint with a torch with no flux and no braising filler usually just leaves an oxide inclusion in the joint. Basically, a void in the solder that is caused by and occupied by oxidized remnants of the material that was leaking. In this case, refrigerant.
|
|