I am working on some mcquay heat pumps but in one of them i am having a problem from some days. In cooling mode all is ok they newer got problems they are air cooled . One of them is having problems in heating mode and give ' Cond press high' alarm . This is a 2 circuit model i have switch off 1 circuit and run the other 1 and the error was the same. I have checked the circulation water pumps and they are ok water flow is ok. Both compressors run for 10 minutes but when they try to increase stage and speed compressor discharge goes 78-80 degrees celcius and compresor suction line temp is about 11 degrees. Water enter 42 degress in condenser and leave 44. It is near to stop for set point temp 45 but nothing it goes in alarm.

I think maybe is a problem with the transducer but the problem happened with both compressors is possible they use only 1 transducer on condenser?

Sorry for my bad english, Can anyone help?