Split or cracked flare nut on expansion valve

[davethefridge]

I have a small cold-room with a thermostatic expansion valve, the liquid line 3/8 flare nut keeps cracking after about 8 months, I have tried different expansion valve seats and have not over tightened the nut could anyone give some advise why this may be happening.

[charlie patt]

Valve incorrect position and allowing water on the threads then cracks or perhaps unit passing a bit to much liquid danfoss do a dedicated orifice flare nut with a flat orifice that has cut outs in the threads to reduce freeze crack ive never had one leak yet

[Rob White]

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There are also two types of valve.

One has a flare nut connection on both the inlet and outlet and the other has a brazed outlet
with a different type of nut for the orifice inlet side.

So as Charlie states the position of the valve is a factor and also the selection.

There are also two types of flare nut.

One is a long body and the other is a short body. If they are at risk of ice damage then
using the smaller flare nut might make a difference.

Regards
Rob

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