SMSChiller
06-16-2010, 04:38 PM
Hey Guys,
I've got a York YCAS R-407C chiller, 3 Years ago (our first with the account) I showed up in spring to start the chiller and found circuit #1 refrigerant charge completly gone(220 lbs.). I took the standard approach and pressureized system with dry nitrogen and tracer gas upto 250 PSI and leak checked the system must have gone through the complete system 3-4 times and couldn't find a single leak, since the chiller wasnt needed to run I decided to leave the pressure on the system overnight to see if it held. Well, it held so I blew off the pressure and put my vacuum pump on the system over night. Returned to site in the morning and found system had a 400 micron vacuum, decided to let that stand for 24 hrs, returned the following day and it was still at 400 microns.. Well appears there isn't a leak, system cannot hold 400 micron vacuum for that time period if there is a leak. Charged system and started unit.. System ran fine all summer when spring rolled around again we were in the same situation.. Went through the same process as before and again found absolutley nothing... So last fall we pumped the system down and vlaved everything off, this year went to start up chiller and found no problems unit is running good with no refrigerant loss.. So my question for you York guys, have you run into this situation before? The only thing i could think of is (cold winters up here) that possibly during the winter the chiller barrel heaters are raising the evaporator pressure to the point where it is forcing the relief valve (inbetween evap and compressor suction) to bleed off the charge over the winter... I did install a new relief valve the first time based on the fact that I couldn't find a leak and thought that my be the guilty object.. there is no sign of oil loss anywhere which makes sense if it is a slow leak while system is shut down.. Any input on similar situations would be greatly appreciated!! Thanks!
I've got a York YCAS R-407C chiller, 3 Years ago (our first with the account) I showed up in spring to start the chiller and found circuit #1 refrigerant charge completly gone(220 lbs.). I took the standard approach and pressureized system with dry nitrogen and tracer gas upto 250 PSI and leak checked the system must have gone through the complete system 3-4 times and couldn't find a single leak, since the chiller wasnt needed to run I decided to leave the pressure on the system overnight to see if it held. Well, it held so I blew off the pressure and put my vacuum pump on the system over night. Returned to site in the morning and found system had a 400 micron vacuum, decided to let that stand for 24 hrs, returned the following day and it was still at 400 microns.. Well appears there isn't a leak, system cannot hold 400 micron vacuum for that time period if there is a leak. Charged system and started unit.. System ran fine all summer when spring rolled around again we were in the same situation.. Went through the same process as before and again found absolutley nothing... So last fall we pumped the system down and vlaved everything off, this year went to start up chiller and found no problems unit is running good with no refrigerant loss.. So my question for you York guys, have you run into this situation before? The only thing i could think of is (cold winters up here) that possibly during the winter the chiller barrel heaters are raising the evaporator pressure to the point where it is forcing the relief valve (inbetween evap and compressor suction) to bleed off the charge over the winter... I did install a new relief valve the first time based on the fact that I couldn't find a leak and thought that my be the guilty object.. there is no sign of oil loss anywhere which makes sense if it is a slow leak while system is shut down.. Any input on similar situations would be greatly appreciated!! Thanks!