R290 undercharge in 1 ton cap tube split sytem heat pump? - Page 4

Thepprof · 04-02-14, 12:41 PM

Recently added r290 to a r12 frig first run -17 f in the frig part. I now have a Minisplit that locked up the compressor. Pulled the toshiba and put in a old wrpl from a window ac installed it threw insome r290 in 20 min Delta 24. Just took a shot.

randallkc · 08-15-16, 08:22 PM

I have used R290 on r22 capillary systems. It does not work well at all. Sub cooling is awful. The tubes are not correct for the fluidity of r290. They need to be about twice as long to work well. That said. You need to use a TXV and tweak the valve for the proper sub cooling. Cap system conversion with out resizing the tubes is a disaster!

randallkc · 08-15-16, 08:33 PM

Even though the thermal characteristics are very similar and r290 can serve as a replacement for r22 there is one big consideration that has to be accounted for. The orifice requirements of r290 are way different. It is more fluid. Requires more of a restriction than R22. With a TXV you can tweak it to get it in the range it needs to be and the thermal characteristics in the bulb will keep it in line. Using a piston you must down size and cap tubes need extended.

If you drop in R290 and don't change the orifice you will be disappointed. It is a great product and I use Rhino gas I pre-filter with a drier and the stuff is amazing. But the orifice is the kicker with this stuff.

I scavenge R22 on systems I discover have leaks. When I replace a A coil I use a TXV and convert to R290. I have about 40 systems under my care.

R290 is great stuff. But the information out there on it is hard to come by. I think as it gets more popular it will be common place. I had to learn some of it the hard way.

08-15-16, 08:33 PM	#33
randallkc Lurking Renovator Join Date: Jul 2016 Location: Kansas City Posts: 6 Thanks: 0 Thanked 1 Time in 1 Post	R290 Even though the thermal characteristics are very similar and r290 can serve as a replacement for r22 there is one big consideration that has to be accounted for. The orifice requirements of r290 are way different. It is more fluid. Requires more of a restriction than R22. With a TXV you can tweak it to get it in the range it needs to be and the thermal characteristics in the bulb will keep it in line. Using a piston you must down size and cap tubes need extended. If you drop in R290 and don't change the orifice you will be disappointed. It is a great product and I use Rhino gas I pre-filter with a drier and the stuff is amazing. But the orifice is the kicker with this stuff. I scavenge R22 on systems I discover have leaks. When I replace a A coil I use a TXV and convert to R290. I have about 40 systems under my care. R290 is great stuff. But the information out there on it is hard to come by. I think as it gets more popular it will be common place. I had to learn some of it the hard way.

04-02-14, 12:41 PM	#31
Thepprof Lurking Renovator Join Date: Jun 2012 Location: Virginia Posts: 28 Thanks: 0 Thanked 4 Times in 3 Posts	Recently added r290 to a r12 frig first run -17 f in the frig part. I now have a Minisplit that locked up the compressor. Pulled the toshiba and put in a old wrpl from a window ac installed it threw insome r290 in 20 min Delta 24. Just took a shot.

08-15-16, 08:22 PM	#32
randallkc Lurking Renovator Join Date: Jul 2016 Location: Kansas City Posts: 6 Thanks: 0 Thanked 1 Time in 1 Post	I have used R290 on r22 capillary systems. It does not work well at all. Sub cooling is awful. The tubes are not correct for the fluidity of r290. They need to be about twice as long to work well. That said. You need to use a TXV and tweak the valve for the proper sub cooling. Cap system conversion with out resizing the tubes is a disaster!