R 422D Expansion valve problems?

[neil74]

Hi everyone,
We have recently converted a DX water chiller from R22 to R422D and we are having problems with getting the correct duty/superheat/suction presure when the chiller is fully loaded, it appears we need to increase the capacity of the exspansion valve which isn't to much of a problem but l would appreciate anyone else's experiences with this refrigerant and also if anybody could shed some light on using an R404a expansion valve which l've heard suggested instead of an R22 valve?
Thanks for any comments they will be very appreciated.

[NoNickName]

Welcome in the nightmare of drop in refrigerants.

[Gibbo]

Best you go down Boots and get some headache pills for a start.
The glide on R422D below 8 degrees C is big and as for for it leaking, you will have to replace all gland seals, O rings and anything which has ptfe tape on it.
I am not so sure it is worth the effort.

It is not such a simple exercise as Dupont or Isceon make out so if you want to save yourself and your customer grief i would sell them a new chiller.

Thats my opinion

Good Luck