Chiller in progress...a few questions...

[Frank E. BoNeS]

I've been in the process on converting a 11600 BTU AC into a chiller for the last week. Everything's been going pretty smoothly until now. Some info first.....

I got this AC for free....I'm guessing its about 20 years old. I'm using about 7 gallons of coolant in the res. I had to use such a big res. because the evap. on this thing is MASSIVE and wouldn't have fit into a smaller cooler. Coolant mixture is 70% denatured alcohol, 20% antifreeze and 10% distilled water. Here's a pic of the setup so far....

http://members.skill-club.com/BoNeS/chiller%20010.jpg


I've been testing to see how cold my coolant gets but after about 3-4 mintues of letting the unit run, forst starts migrating from the suction line to the compressor. The coolant temp drops to around -4C after the three mintues but I shut it down in fear of damamging the compressor. Here's a pic.....

http://members.skill-club.com/BoNeS/chiller%20009.jpg

...How long can I run the compressor like this before it's damaged? Will letting some refrigerant out solve this problem? From what I've been reading a piercing valve would be needed to do this. Which pipe would I pierce with this valve?...the cut-off, pinched tube coming out of the compressor? Would I need a set of gauges to do this? Or could I just let a little bit out at a time and test? Also, could I leave the valve there for good? I've also tried kinking the cap tube (you can see it in the pic) in hopes that it would help this.....it hasn't so far ;).

I'm pretty much a newbie to refrigeration so any help would be greatly appreciated.

[kayl]

just place a piercing valve on the high side and let some gas out.
a set of gauges would be ideal and you will also need a bottle with the correct leads to connect to it and collect all of the Freon that you release. (can use it for later projects) make sure you do it at the coldest temp.
while the air conditioner is running open piercing valve a little to let out the gas until the compressor stops freezing(leave it for 15mins or so each time when releasing the gas so it can stabilise, ideally it should be under load, dont let too much out cause you wont be able to put it back in, unless you get two piercing valves this way you will be able to have access to low side as well, this would be ideal.

that is one big ass compressor, with a little tweaking that should be a ok chillier, i bet you had alot of fun bending that evap into place, but you did a very good job at doing it no kinks .:toast:

[Gary Lloyd]

Piercing valves are notorious for leaking. That doesn't mean they always leak, but you take your chances leaving them on the system. On the high side the pressure is much higher, so leakage is more likely.

If you mount the piercing valve on the low side (compressor process tube) you will need to remove refrigerant while the compressor is off, because not having gauges you don't know if it is running in a vacuum or not. If you open the valve while it is running in a vacuum, air will be sucked into the system.

[Frank E. BoNeS]

Originally posted by kayl
that is one big ass compressor, with a little tweaking that should be a ok chillier, i bet you had alot of fun bending that evap into place, but you did a very good job at doing it no kinks .:toast:

It's one big AC. :lol: ...It was a bit of a pain bending the evap. into place but I took it slow. ;)


Thanks for the replies guys.

So if I wanted to remove the valve I would have to pinch then braze the process tube? I don't have any experience with brazing (or tools for the matter) so I think avoiding it would be a good idea for the time being. ;)

Also, I can't seem to find piercing valves anywhere. www.rparts.com doesn't seem to have them and all searches turn up piercing valves for water systems...which I don't think can be used for this. :(

[Gary Lloyd]

You will have to get a piercing valve (aka tap valve, aka vampire valve) from a refrigeration supply. Plumbing valves will not work.

[Frank E. BoNeS]

I'm having a hell of a time trying to find piercing valves. Any ideas on where I could find them? :(

[Gary Lloyd]

Try here:

http://www.e-johnstonesupply.com/main/selectstate.asp

[Frank E. BoNeS]

Originally posted by Gary Lloyd
Try here:

http://www.e-johnstonesupply.com/main/selectstate.asp

Thank you Gary. Sweet...there's a Johnstone Supply about 40 mins away from me and it looks like they have them. :thumbsup: