Pressure controlls Settings

[Rob White]

Hi
just wondering what “rule of thumb temperatures” converted to pressure you lads are using when setting up your pressure controls.

based in England so ambients of 30’c plus aren’t to common.

id like to see what other people use when setting there controllers up.

head pressure settings?

Low pressure Cut in? Diff?




Thanks

We work to the standards.

Standards state 55degc for condensing temp (high side) and 32degc for low pressure side.
If setting up safeties then you set HP to x 0.9 or 90% of that value for the high side. If you are setting PRV then that is x 1.1 or 110% of maximum working pressure.

I see you are mainly AC? R410A at 55degc is about 33barg so safeties set to 30ish and blow offs to 36ish
Hp switch auto reset at 32degc so it would need to cool down below 20barg before restarting.

R404A on the other hand is a lot lower pressure so R404A @ 55degc = 25barg. Safeties set to 22barg - 23barg and blow offs to 28ish barg. auto rest on HP at 14barg.

So no guess work, it should all be done to EN378 and obviously manufactures specifications but manufacturers always work to EN378 anyway.

Rob

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[Airconking]

Thanks for the reply rob...
I’m using 50’c as a ball park figure for my high side safety’s this obviously takes into account the 90% rule you mentioned using EN378.
If I use 55’c - 10% or just a 50’c with no deduction there pretty much the same figure anyway using r404a.
ill stick to this then because like you said it’s working to EN378