Had a leak on a York one time that no one could find. Went on for a couple of months and no one could find it. Then one day another guy was having a go at it with out much luck. He laid his leak detector down on the top of the condenser, and the probe was hanging down on the side of the barrel. The detector went wild. The leak was a small hair line crack in the shell about halfway down. Wasn't near any welds or fittings.
Good point. Sometimes we get so used to finding leaks at fittings, connections, flanges,... etc., that we forget other possibilties like this. We found one once that was a casting flaw in the suction cover of Trane PCV. And it had been in (almost) continous service for several years, with no complaint. The old belt-drive purge was keeping up with it, and this was back in the days when some sites had that annual Spring rite of "time to dump another drum in her".
Update- Just starting annual maintenance on this machine this week..... tubes,oil,filters,tower,pumps,strainers,etc...You guys know the drill. Ive been out of town for a few weeks so I'll respond to the last 3 or 4 replies. The 2 seals that failed were worn and showed signs of excess heat, orings were fine, L.S.thrust checked, new seal pressure reg. installed. I have manually exercised the vane arm while leak checking. I will probably leak check again on Tuesday and after reading jayguy's reply I think I will blow all of the oil out of the sump and get as much oil out of the purge and lines as possible and focus more attn there. Again thank you all for taking the time to respond, it is appreciated.
We have had the oil cooler lines leak on use as well. To prevent the unit from taking on air while not in use you may want to install a prevac system. It will keep the air out, allow to leak chek, and service it without pulling the charge.
PreVac? Hmmm, I might would consider the version with the water heater and recirc pump, but I wouldn't want those blanket heaters on my chiller. But I would worry that the PreVac would "hide" any leaks, especially high side leaks, while the chiller is off. A good operator will inspect and log a chiller at least once a day (shutdown or running), and will verify that a shutdown chiller is at the pressure that it should be, for the temperature that it's at. To determine if it has air, if it's a low pressure machine. The ability to leak check and service is nice, though.
I agree the chiller should be checked every day by the operator. The prevac allows the unit to be serviced or leak chekced easily after being installed. For hard to find or small leak in the chiller it can save on the repair until it becomes worse. We have several of the units in service and have good luck with them. I would not use the blankets either. You can also put them on a two whell dolly and use them at multiple locations.
If it has the original purge, check the purge exhaust check valve when it is in a vacuum. The solenoid valve will prevent leakage when under pressure, thus no leak to detect. Bad check valve will let air leak in after machine shut down when it's in a vacuum.
Just stick your gauges on check valve flare after shut down and watch for vac.
Or just put a spit gob on it! It will show quick. Or take it off and test under pressure, should have no leakage.
Update = I extensively leak checked the machine once more and again found nothing. Just before I started attaching the explosive charges to the machine I remembered what jayguy posted about purge leaks being hard to find due to the oil , so I shut the machine down after the purge went through its drain cycle , took the oil out of the machine , and made sure all oil lines were drained. I pressurized it and started leak checking again and about 5 minutes in I.................yes I did , I found the leak. So you ask where was it (DRUMROLE PLEASE)... on a flare fitting on one of the purge solenoids. It was a substantial leak = leak detector screamed on the large setting and bubbles galore. You know the crazy thing is Ive checked that particular fitting both electronically and with soap probably 15 times , never picked up a trace , not a single bubble , and not a drop of oil on or under the fitting. I am relieved. Thanks to all that posted.