Thread: HyChill in 2.7 or 3.0

Originally Posted by BradC

Generally (and I say that with only the knowledge gleaned from manufacturers manuals and data sheets) a variable displacement compressor will stop at about 5% displacement.

Hydrocarbons pick up and move lubricant orders of magnitude better than r134a (which is frankly a **** refrigerant anyway and terrible with oil, which is why they need crap like PAG because it's the only oil that crap will move around).

In unloaded situations,there is also less refrigerant velocity,so oil return can be an issue.

In our game,we never have issues with oil return using R134a,there are much worse refrigerants around,such as R22,particularly at lower SSTs.
Even with 50/50 POE/Mineral oil,134a is fine.

Originally Posted by BradC

Pah, easiest leak detector for HC's is a lighter! I joke.... mostly.

I'm still using an old heated diode unit. If I were relying on it for a crust I'd certainly upgrade but the sensitivity difference between HCFC and HFC is at least an order of magnitude on my old clunker. I've kinda looked at both the IR and ultrasonic units over the years, but as I have to slip it past the war office it's a hard sell for the couple of times a year I break it out.

I did have one leak that was a complete bastard to find. I ended up wrapping the whole pipe segment in gladwrap and then just poking holes in it to stuff the leak detector into. Turned out to be a smaller than pinhole in a brazed joint. Not even big-blu bubbled up, but after half an hour in gladwrap it showed itself.

I could write a book about where and how hard some leaks were to find and where they were.....

One i can remember was a little refrig unit,i endeded up bringing it home,taking all the electrics and fan motor off it,and putting it in the pool,it was a pin hole on the shell of a Danfoss drier,corroded from the inside.
No sign of any oil,which is often the case on the liquid line anyway.

Sometimes,with say evap coils,even pumped up to 300PSI,and put in the pool.there is only the tiniest of bubbles every 15 to 30 seconds or so,and that is enough to cause a problem.