HP/LP settings on R134a

[smokersuk04]

hey guys, finishing off an install of three new condensing units to three remote chillers, all identical on R134a. whats should i set the HP/LP switches to??

[Brian_UK]

What do the manufacturers of the chillers specify for the settings?

[dirk]

If there is no manufacturers specs, then depending on whether the switches provide a control or safety function they will need to be set up to accomodate the operational requirements of the chillers ( You will need the operational specs of the chiller for this specific application)

[sendhilkmar]

I agree with Dirk. You can refer the compressor operating envelope and set LP/HP according to the lowest and highest possible operating Presures.

[lana]

First you estimate the operating conditions i.e. evaporating temp and condensing temp.
Set LP below the operating pressure and HP above the operating HP.
If you set these very close to the operating conditions then you will get unwanted cut outs. Set them reasonably.
Cheers

[chemi-cool]

High set can be 200psi.

Low set depends on how the system stop and if there is an SV that runs parallel to the compressor or as a pump down control.

Is it manual reset or automatic one?

Bring more details and get better answers.