McQuay PEH 087 Chiller Won't Start for Vane Close Switch Open
Got a phone call from my friend asking for help from jobsite this afternoon, he failed to start his McQuay PEH 087 chiller due to vane close switch open alarm, as what he told me, he unloaded the vane by manually running the oil pump for several minutes and the faulty condition corrected, and this condition has been persisting for quite a period of time.
I think it will be better for me to reach the jobsite to check it myself,
before I go, I would like to ask for some information for the hydraulic system in advance and hope those professional technicians in this forum can kindly provide related knowledge to me,
My questions so far are;
1. What is the mechanical structure of inlet vanes to open and close inside compressor?
2. What exactly is the vane close switch, some kind of limit switch?
3. What is the most possible cause for the faulty condition described above, how to clarify and fix it?
Any advice will be much appreciated.
I would put a tee on the load line and the vane closure line. hook up gauges and turn on machine. the oil pump should be on and unload should be powered. if the vanes is closed you will have close to a 100psi difference on those two ports. if not your vanes are not closed. This is assuming you have app 100psi oil pressure to begin with. also verify your 4way valve is powered correctly. there is a number of o-rings in the front end that can prevent the piston from moving. Now if you do have oil pressure differential the switch is bad. then it will need to be replaced. the vane switch prevents chiller from starting if they are open. you can remove the switch and hook it up to nitrogen and see where it makes and breaks. should be around 50psi.
could also be bellows in v/c switch leaking by,or little bits of o-rings pluging up v/c port
sorry for having replied late and thanks for your advice,
the problem has been solved, it is on the switch itself,
will take picture and post it,
again, thanks for the help.