to pinch or not to pinch

[Brutus]

I have been reading this forum for a couple of months now and because you guys made it look so simple i started building a waterchiller.
I got my hands on an old 8000 btu ac window unit and put the whole thing together.
Now my question is :i now get a temp of -27 C max , no load (pc is not hooked up yet)
The ac unit is charged with R22 by an hvac engineer.
Is there any way to get this temp lower ?
I thought maybe pinching the captube a little ?

[Blergo]

well, there is a lot more to it to tweak the system, first you ideally need to work out your heat load and replace the cap tube completely or lengthen it for your load (which you will need to know to work out how long the cap tube needs to be, then you will need to tweak the refrigerant charge to give you the best temperatures under load. or atleast this is how i did my mates chiller, mine i havent got round to changeing the cap tube and stuff on yet as i am replaceing it soon so there isnt any point at the moment. :) hope someone else can help explain things a bit better though. :) another thing is insulation.. make sure everything is insulated properly, and gat some photos for us all :D we love photos :D
owen

[Brutus]

Well the problem for me is when i change the captube i have to recharge it,witch for me is impossible to do because you have to have to have certain papers in holland to buy R22 or any of those kind of gasses.
And the last time i let it be charged it costed me about 150$ so i would not like to do that right now.
About those pictures , i'll try to post them .

[Gary Lloyd]

Everything works together. When you change one thing, it effects everything else. If you change the refrigerant flow, by either pinching or replacing the cap tube, then you will need to adjust the refrigerant charge to get maximum performance.

[Brutus]

Ok here are some foto's (i hope)

[Brutus]

next

[Brutus]

and another one

[Brutus]

Yes Gary i understand that,but the only thing i can do myself is let some gas out, and to charge it i have to go to the hvac engineer.
But is it possible to get lower ?? (with r22)

[Gary Lloyd]

But is it possible to get lower ?? (with r22)


Yes, it is. It depends on many factors, but with the proper cap tube and charge, you should be able to get at least -40C or better with no load, using R22.

[Brutus]

So should i try pinching it or not,Gary ?
And when i pinch it should i let some gas out.
or just try it with load and see if it keeps the temp.
btw wish i was in the usa then i could charge it myself

Anyone?

[OCme]

If you pinch it then you will change the refrigerant flow, and when you change the refrigerant flow you will need to adjust the charge by letting some gas out to optimize performance.

[OCme]

I have never pinched a cap tube, but if you are going to attempt it, then pinch it a little bit at time, and then wait for about 20-30 min to see how it affects your temps. Make sure your coolant is at its lowest temp before you start. I understand that several small pinches are better than one large one. Each time you pinch the tube feel the bottom of the compressor because you want it to be warm to the touch not hot.

[Brutus]

Ok thanks, i am going to try it as soon as i got it hooked up to my comp.