Mcquay Chiller -PEH126-LUB OIL SYSTEM

[PRASADA]

HAllo
We have Mcquay PEH 126 chillers . As per manual whenever the LUB oil trips due to any reason , OIL from a resorvoir supplies oil to bearings by gravity and eventually the chiller trips on LOW differential pressure .

But it doesn't work, and by the time it coasts down the impeller and high speed shaft gone due to in sufficient oil flow.WE have experienced this on 2 chillers. Looks like there is a flaw in the basic design.Normal OIL pressure is 100 PSIG .OIL from resorvoir can give may be 3 psig and even if it is pressurised by Evaporator ***** , it can be only 35 PSIG. How can a high speed bearing sustain such low pressure when it is designed for 100 PSIG.?

Look forward to the experience and advise from other forum members and Mcquay.

[sedgy]

hi prasada, most semiemetic compressors have an oil pump to give a pressure higher than the suction psi, regards sedgy

[binti]

Mcquay use spring pressure to supply oil to high speed shaft in a coast stop. When the oil pump starts it primes a reservoir or a piston with a spring behind it. It is NOT gravity fed. If a power failure occurs the piston under spring pressure supplies oil during coast stop.
If you are loosing oil pressure during coast stop i would be looking at the spin down piston and spring etc. i think it is in opposite the filter. Filter on top and piston on bottom. Or visa versa.

Hope this helps.

[PRASADA]

Piston /Spring pressure type is given in other types and not in model PEH -126. We have checked up this and there is no spring.