Originally Posted by flocko
Receivers are typically used on systems that use a txv as a metering device for the refrigerant . Not always but usually. In a cap tube metering situation you will be charging the unit for it's maximum load holding capabilities at lowest evap temps. So no need for a reservoir to hold excess refrigerant (receiver) in your situation. Cap tube units are intended to be used at there maximum potential at all times the unit is on.
Drew gave you purging options as far as gases go and those are the obvious choices for pressure testing . I'll leave it at that
I would prefer to see you vacuum the suction line after it is brazed to the evap / prior to brazing to the compressor than use refrigerant as a pressure testing medium.
BTW ... don't forget to lap the evap face prior to brazing the suction line to evap or you will never get it truly flat .
My opinion only !
There is a fine line between the obvious and the convenient.
I already finished sanding on 150 grit. Next I will move to 400 then 800, then braze on the flex line, braze everything else up, and then when I am ready to mount I will do a final polish with my ICD7, use articlean, them mount with Ceramique 2.
Originally Posted by Sdumper
If that's not a reference to that reciever building project of Nol's on Xtreme System's a couple years back then I have no idea what you are talking about. (Amazing. All the research and reading of build logs in a frivolous attempt to avoid the mistakes everyone else made, yet I still feel like I have absolutely no idea what I am doing
Originally Posted by Drewmeister
I believe DD meant an accumulator, the answer is yes you'll need one for high load. I take it scott is going to show you how in pm.
You can't rely on a standing vacuum test for leak checking as there are too many variables that can affect the reading. Also vacuum is basically only a 14.7psi pressure test at sea level. The standing vacuum test is more for indicating moisture in the system.
Leak check with nitrogen to 150psi like scott said. You could also use compressed air for the evap or the r404a or r134a if you have to.. it won't take much. If you're asking if you can charge gas vs liquid then yes for that small amount... just not for filling the whole unit.
Inspect each joint carefully as you braze. A 5x dental mirror comes in handy here. Once all joints are brazed then the next step would normally be a leak check with 150psi nitrogen and leak detection solution(soapy water). Since you don't have nitrogen then I would make sure the unit pulls down to at least 200 microns, then charge r404a and leak check. There is a way you can charge mostly gas with the bottle inverted for liquid. I can explain that later if you're interested.
I thought he meant an accumulator too, but no, a reciever.
So then I will go on with the final construction and do an initial gas charge just to check for leaks, then pull a vacuum, and charge as a liquid for a final charge.
If you guys can't tell by now
I kinda have to cheap out wherever I can as this is a personal project. If all goes well and I decide to build for others then I would be able to afford to buy this so-called "standard equipment."
(I guess I may as well schedule my first commercial build for December 22nd, 2012 )Edited by dinkledork - 8/26/11 at 8:38pm