Manual expansion valve

[1001yos]

I’m looking to construct my own refrig system using r404. I want to be able to change the temperature of the evap coil. I’m looking to to vary between-30c and -50c. I’m prob going to use a compressor between 1/3 and 2/3 hp.

Is there something on the market that exists? Does it have to be packless? I could use a cap tube, but it would be a lot of guess work as I’d like to use salvaged parts.

Thanks!

1001yos

[Brian_UK]

I would suggest an electronic expansion valve but it might not be cost effective.

Although you might be able to salvage an EEV from a modern AC unit you will have to either invest in a controller for it or build your own.

[monkey spanners]

Have a look for a suitable 'Automatic Expansion Valve', they control the flow to the evaporator by maintaining a set pressure which you can adjust maunally.