PRV's

[techni]

I recently had two DX downflow CCU's installed, on commissioning I noticed that there were no PRV's on system. Each unit is 40kW on 407C. The German manafacturer says that they are not a requirement. What are you views on this.

[al]

I thought they were only required if you had a receiver over a certain volume?

Alec

[SteveCass]

i thought the same as al, thought that the system had to have a receiver or a total charge over a given amount? something like that?

Steve

[Grizzly]

Al and Steve are correct it is all about system size.
I cannot remember the exact formulae.
But I will try and dig it out.
I think you will be surprised as to how big a system can be.
Grizzly

[Gingerair]

Interesting topic, does anyone know if there is consideration in the PRV or pressure equipment directive regs if a unit is exposed to a building fire ?
Also wary of water cooled vrv's, seen a few were the water temp was +70c..
Ginge :)

[Magoo]

PRV's pressure regulation, where in system?. Evap regs, crankcase regs, discharge regs,
German manufacturer may have installed MOP txv's so would be no need for Evap reg or crankaces pressure regulation.
Did a new coldstore and installed MOP TXV's plus a suction/ evap PM valve as insurance after defrost, ended up removing PM regulation and reduced suction losses by 2 'C. the MOP's worked perfectly.
magoo

[al]

Magoo

These are pressure relief valves, purely safety!

Alec

[Magoo]

Thanks Al.
the picture has become very clear, cheers ta..,
abbreviations and interprutations, is it too hard to put the whole word in.
OK prv's are based on free air capacity/ versus vessel volume.

[Grizzly]

PRV or pressure equipment directive regs if a unit is exposed to a building fire ?
Also wary of water cooled vrv's, seen a few were the water temp was +70c..
Ginge :)

That's what fusible plugs are also used for. The use of these is refrigerant specific though.
Grizzly