Pressure Transmitter R134a Setpoints

Hi!

First of all, I thank you for reading this thread.

We have completed retrofitting a York Chiller from R500 to R134a. The chiller model is M238A7. It is a 2 stage centrifugal.

It has a pressure transmitter that controls the PRV position with pheumatic pressure output. This output is proportionate to the min. & max. preset values of the condenser pressure. The transmitter is from Foxboro, Model # 11GM-CS2 ST-D.

After the convertion, this transmitter may require recalibration to conform the R134A operating pressures.

My questions are as follows:
1. Does the transmitter really requires recalibration taking into consideration the pressure difference between R500 and R134A is quite minimal?

2. Were can we get a certified setpoints for this transmitter and R134a?

Thanks a lot for your share.

JANEW :confused: