1990 honda retrofitted to R134 , holding pressure, holding vacuum , not cooling

[greenquark]

Updates:

I have an expansion valve at home, I have been playing with. I noticed there is an allen nut taht you can turn and close/open the flow. Is there any specification to set it right for R134a? Like number of turns from a tightening position?

Cheers

[mk378]

Don't turn it at all. Look on the top of the valve it often says R-134a. In any case, the difference is slight enough that new TXV's are set up to to work with either refrigerant.

The screw changes the temperature-pressure response of the valve not a fixed opening. Adjustment requires operating the valve under pressure in a test rig, which they did in the factory for you.

[greenquark]

Thanks for the info. I took it from an old evaporator. I had no idea whether it work or not. So I was testing it to learn how it really works.

I put the bulb in Water with ice and it didn't close, but I put it in the freezer and it did...I tighten the allen nut a bit and it close a bit when I put the bulb in icy water. I was trail-error until the valve closed at that temperature ( icy water). I thought you could control the performance of the TVx by moving the screw in or out.

By the way , the Tvx came from a 1991 honda...it does not say R134a anywhere. That is why I was asking if you could calibrate by the number of turns.

[mk378]

I wouldn't trust a used TXV. A new one is only about $20 and good to go with R-134a.