Wrong Txv for refrigerant type

[monkey spanners]

Got called to a DX milk tank on R22 but someone had previously changed the txv and fitted an R134a one....

I checked the standing pressure and looked it up on my trusty slide rule and it confirmed R22 pressures (so the refrigerant hadn't been changed too) so i chucked a new Tex2 and n'3 orifice (5.3 kw) on it.

I have been trying to work out what the R134a valve would be doing and i think it would be thinking that the superheat was way too low and would move to a closed position, what do you guys think?

It had a n'6 orifice in it (10kw), and i think it would have just worked like a fixed orifice system.

The superheat pixie had not been at the adjuster though

Jon

[monkey spanners]

Oh and it had been like this for three years or so and the customer hadn't noticed any loss of cooling duty

Jon

[chemi-cool]

The main different is the refrigerant in the sensing bulb. Apart from that, I think they are pretty much the same so if it was tuned correctly, I wouldn't worry too much but would change it the proper one.

[monkey spanners]

The main different is the refrigerant in the sensing bulb. Apart from that, I think they are pretty much the same so if it was tuned correctly, I wouldn't worry too much but would change it the proper one.

I think you are right, the valve construction looks the same, just the charge in the bulb is different. With the sporlan ones that were original equipment on these tanks i just change the element/bulb, easier and cheaper than a new valve.

I was just wondering how the system would run with the wrong valve fitted.

Jon