Mr-Frosty
16-12-2010, 06:02 PM
Firstly i will give you a run down of the job.
I attended the site of a deep freeze cold room on r404a there are 4 units and 4 evaps in this cold store.
i cant remember the model number of the compressor off hand it was a 6 cylinder model. anyways i dound the unit kept tripping on oil pressure so i reset the unit it ran for 90 seconds then cut off again. my suction pressure was 15 psi (roughly) as it didnt run for long enough and liquid was about 220 (roughly) the coldstore was at -19 set at -22 i checked my oil pressure and had between 25-30lb whilst the unit was running and the oil level looked a little low. there was oil coming back from the seperator so i pumped the system down a few times and i drained the oil from the system. i cleaned the oil filter and added 5 litres of fresh oil to the system. i ran the system again and exactly the same problem as before. i put the problem down to being a faulty oil pressure switch. i couldnt get hold of the oil switch due to suppliers out of stock through bad weather and minimal deliveries so my only option was to wire out the switch for the weekend (now thursday) so the customer was with full use of his coldstore. well we recieved a call out on sunday afternoon to this unit. when i arrived the flare had split on the sump from the oil seperatore and thrown the oil from the system and smashed the compressor to pieces. the pressure was the same on both hp lp sides and suction side was warm.
we managed to get hold of a re manufactured compressor and i fit it today. i completely re made the oil line as i thought it may have gone brittle i pressure tested the system fit a new oil pressure switch vacced the system for 24 hours and re charged. i clamped out the new compressor i was averaging about 14-15amps per phase one one set of windings and about 10 aps per phase on the second set of windings. i had oil pressure of about 50psi and the system seems to be working spot on including all safety cutouts. the oil line seems a tad warm to me and there is oil coming back to the compressor. id say at a guess the oil return is around 55 degrees C
i have a suction pressure of 15psi and liquid at 240psi
my questions are-
what could have caused the failure of the first compressor?
what could cause the rupture of the oil line?
id just like a few answers for piece of mind
thank you for your time
Mr-Frosty
I attended the site of a deep freeze cold room on r404a there are 4 units and 4 evaps in this cold store.
i cant remember the model number of the compressor off hand it was a 6 cylinder model. anyways i dound the unit kept tripping on oil pressure so i reset the unit it ran for 90 seconds then cut off again. my suction pressure was 15 psi (roughly) as it didnt run for long enough and liquid was about 220 (roughly) the coldstore was at -19 set at -22 i checked my oil pressure and had between 25-30lb whilst the unit was running and the oil level looked a little low. there was oil coming back from the seperator so i pumped the system down a few times and i drained the oil from the system. i cleaned the oil filter and added 5 litres of fresh oil to the system. i ran the system again and exactly the same problem as before. i put the problem down to being a faulty oil pressure switch. i couldnt get hold of the oil switch due to suppliers out of stock through bad weather and minimal deliveries so my only option was to wire out the switch for the weekend (now thursday) so the customer was with full use of his coldstore. well we recieved a call out on sunday afternoon to this unit. when i arrived the flare had split on the sump from the oil seperatore and thrown the oil from the system and smashed the compressor to pieces. the pressure was the same on both hp lp sides and suction side was warm.
we managed to get hold of a re manufactured compressor and i fit it today. i completely re made the oil line as i thought it may have gone brittle i pressure tested the system fit a new oil pressure switch vacced the system for 24 hours and re charged. i clamped out the new compressor i was averaging about 14-15amps per phase one one set of windings and about 10 aps per phase on the second set of windings. i had oil pressure of about 50psi and the system seems to be working spot on including all safety cutouts. the oil line seems a tad warm to me and there is oil coming back to the compressor. id say at a guess the oil return is around 55 degrees C
i have a suction pressure of 15psi and liquid at 240psi
my questions are-
what could have caused the failure of the first compressor?
what could cause the rupture of the oil line?
id just like a few answers for piece of mind
thank you for your time
Mr-Frosty