R12/R134A relief piping

[250x]

We just installed a new 134A chiller and someone said that we can't tie the relief line in because its a different refrigerant. Any truth to that?

[gsxrsquid]

you are talking about the relief vent that vents to atmosphere when the rupture disc/relief valve operates in case of excessive pressure?

[jayguy]

if you are changing over from R12 to R134a...you will probably be ok. i can't seem to find my pressure relief charts. if you are changing from some other refrigerant to R134a, you will most likely have to change your piping size.

[250x]

The long of it is this. There were three 800 ton Carrier 19EA chillers. One was replaced with a York 123 chiller which has its own relief line now because its a low pressure machine. So now there will only be two chillers on the 6" line. The design engineer gave me a story that the plan checker said you can't mix the refrigerants on the relief. I don't believe that to be true.

[pecmsg]

Mixing the refrigerants in a relief line is not a problem. Your question should be can the line handle the flow???

[Healey Nut]

2 chillers into one relief line is a dumb idea. If a tube fails in one chiller chiller A fills with water pressure increases and ruptures the disk, relief line fills with water if the relief line has enough height to create sufficient head of water the disk on chiller B IMPLODES and fills with water you now have double the problem , solution 1 chiller one relief line 2 chillers 2 lines .Relief piping is alot cheaper than a chiller filled with water. No you cannot mix refrigerants in the relief line especially high and low pressure .

[jayguy]

2 chillers into one relief line is a dumb idea. If a tube fails in one chiller chiller A fills with water pressure increases and ruptures the disk, relief line fills with water if the relief line has enough height to create sufficient head of water the disk on chiller B IMPLODES and fills with water you now have double the problem , solution 1 chiller one relief line 2 chillers 2 lines .Relief piping is alot cheaper than a chiller filled with water. No you cannot mix refrigerants in the relief line especially high and low pressure .

he's got it! i have seen 2 chillers piped together, but they were both low pressure chillers of the same refrigerant. in one case the rupture guard blew on one of them but it did not ruin the other...but it was probably real close to doing it. separate relief piping is best.

[250x]

These are both high pressure machines - R12 and R134a

[jayguy]

it really comes down to what your local codes say. from an engineering standpoint, you are probably going to be okay with the R12 and R134a in the same pipe and the R123 on a separate relief pipe. but i think technically, and according to all of the charts that i have ever seen, only the same refrigerant can be piped together.

but once again...every chiller should have its own relief piping. this will protect the other chillers in case one of them lets go!

[doc ice]

We just installed a new 134A chiller and someone said that we can't tie the relief line in because its a different refrigerant. Any truth to that?

This has to do with state and local codes, also are there other machines connected to this line, is this line going outside or to a storage tank in another room, is the diameter of the line sufficent?