MHI 5/8 service valve

[Craig Johnston]

Hi guys

The company I work for have about 200 of these units in my area alone ( Fdcva502henar ) and probably over 1500 units in the uk. Speaking to the other engineers we are finding that about 60% of units leak from the 5/8 valve. I actually pressure tested one with ofn, when the pressure got to about 25bar the cap blew off like a bullet. I was so lucky not to be standing in front of the unit. Anyone else have issues like this?

Thanks

[cadwaladr]

What refrigerant is being used in this equipment,are you not exceeding test pressure.

[Craig Johnston]

R410a it's fine at that pressure.

[nike123]

These are for R410A!

What cap has blow off? The one which cover the stem of valve? If that is the case than someone has already tried to stop leak by over-tightening that cap and by doing so deformed the cap and valve winding! O-ring of the valve stem should be changed with correct sized one after refrigerant recovery. You need to make special tool for reshaping original bore of valve deformed from over-tightening of cap and then remove stopping ring before valve stem removal.
Valve cap is not designed to be 100% gas tight, because material of valve and cap is too hard for that!
Therefore you need to change O-ring!

I see that kind of leak all the time! No matter what manufacturer. But not in that magnitude!

[Craig Johnston]

15053

Here is a photo, you can see where the brass cap is about to pop

[RANGER1]

Whatever the problem it should be reported to supplier/manufacturer with evidence of what you have found.
If a cap blew off it's not fit for purpose.
If your company buy's so many they probably have a bit of power over them.
Could you forgive yourself if someone did get injured or killed because of it & you said nothing?

Interesting as well that you have gauge line on schrader valve, what happens when you remove hose, does it release a bit of refrigerant?
I thought schrader core depressing tool was the way to go, or pump unit down before removing gauge hose, unless I misunderstand connector you are using.

http://www.airwholesalers.com.au/index.php?route=product/product&product_id=334

[still learning]

Must say it looks as it was over tightend at sometime , did see this on a com's room split where the suction pipe had frozen .
also notice that the outdoor isolator has been wired in pump flex , which will in time degrade and rot depending on the sun