Help design my new system please

[NiHaoMike]

That gauge would work for the high side but is worthless for the low side. You simply won't be able to read the low side with any useful accuracy.

For the low side, try this one:
USG | GAUGES, HOSES, MANIFOLDS | GAUGE PRESSURE RANGE 160PSI | Surplus City Liquidators

Note that if you're planning to permanently mount the gauges, it can be a pain to make a 100% leak free connection. Use plenty of teflon tape and some Nylog, then hope for the best. And as I mentioned, a temperature sensor can very accurately check the low side pressure by sensing the temperature just after the expansion valve. The high side is trickier but a temperature sensor mounted somewhere near the middle of the condenser might give good results.

[jeff5may]

Originally Posted by NiHaoMike

That gauge would work for the high side but is worthless for the low side. You simply won't be able to read the low side with any useful accuracy.

For the low side, try this one:
USG | GAUGES, HOSES, MANIFOLDS | GAUGE PRESSURE RANGE 160PSI | Surplus City Liquidators

Note that if you're planning to permanently mount the gauges, it can be a pain to make a 100% leak free connection. Use plenty of teflon tape and some Nylog, then hope for the best. And as I mentioned, a temperature sensor can very accurately check the low side pressure by sensing the temperature just after the expansion valve. The high side is trickier but a temperature sensor mounted somewhere near the middle of the condenser might give good results.

PLEASE FOR THE LOVE OF MACHINERY DON'T USE TEFLON TAPE ON REFRIGERATION UNITS! When you tighten up the threads, the teflon shreds into little bitty pieces. If any of those little bitty pieces ever get inside the system (happens a lot in industry), they will lodge in something and cause mayhem. I believe teflon has an insatiable love for moving critical parts.

After replacing or rebuilding who knows how many expensive things, I have vowed not to use teflon tape except in emergencies. Kind of like using fix-a-flat. This is what nylog was invented for: it's oil-based sealer glue. If it migrates, no harm, no foul, it's OK. In nearly all cases, there is another product that will do the same job as teflon tape with no risk involved.

[Mikesolar]

Totally agree with Jeff. Most leaks I see are due to T-tape. There are paste products that work really well for this application. I use Nylog but usually only for schreader caps etc.

ww.gfthompson.com/index.php/masters/masters-pipe-thread-sealants-detail

Although guy in the picture is a bit messy, IMO

[Mikesolar]

Originally Posted by NiHaoMike

You should be able to find a grade of 1/2" with a higher working pressure.

Given the size of your system, I would still use 3/8" liquid line and 5/8" or 3/4" on the vapour line. You MAY find that you will get some flashing on the liquid line with one that is too big (all depending on how you pipe it, BTW)

[AC_Hacker]

Why does this thread not have a system diagram?

It would improve the dialog.

-AC

[NiHaoMike]

Originally Posted by jeff5may

PLEASE FOR THE LOVE OF MACHINERY DON'T USE TEFLON TAPE ON REFRIGERATION UNITS! When you tighten up the threads, the teflon shreds into little bitty pieces. If any of those little bitty pieces ever get inside the system (happens a lot in industry), they will lodge in something and cause mayhem. I believe teflon has an insatiable love for moving critical parts.

My set of Yellow Jacket gauges came with teflon tape on the gauge threads from the factory. They think it's OK?

[buffalobillpatrick]

BTW, my solar tank is not a cheap plastic tank.

It is about 1/4" thick in field & 1/2" at bottom, HD fiberglass made for High Temps. It's a cylinder 10' x 4.5' made for Cray Computers as part of their water cooled super-computers 20-30 yrs. ago.

It would hold 1200 gal. but I don't want the water level up to a side port close to top thats about 8" in diameter which I will use for all pipes & sensors from tank to basement.

Another CL score!

BBP

[buffalobillpatrick]

dhaslam,

"That doesn't sound right. I use a calculation of about 6 watts per metre which would be about 7 watts per foot pipe run. I have 1/2 mile of pipe for a 2500 sq' bungalow. Of course being close to passive standard less than half if the circuits are used normally. South facing rooms and kitchen usually have enough passive heat."

what don't sound right?

You designed for 6 W x 232.25 M2 = 1394 Watts = 4,767 btu/h for 2500 ft2 house.

BBP

[buffalobillpatrick]

Could I get some estimates for my compressor output temp. & pressure ????

I found that propane @ 150* F = 344 psi

I'm trying to select ACR tubing & high pressure cut-out

Does this sound about right. 80*C = 31.43 Bar = 456 psi ?

BBP

[NiHaoMike]

150F condensing should easily get 145F water. The high pressure control I listed is preset to 425 PSI, so just make sure the high side is rated for that or higher. You can use a thermal sensor on the condenser to set a lower limit.