I maintain a condenser pack with 3 Bock HGX5/725-4S piston compressors.

Since first installed the pack has seemed oversized for the load - 1 Freezer & 1 Blast freezer

For the last few years the blast freezer has been out of use.

Recently one of the 3 compressors failed & on dismantling we found a snapped con-rod & consequential collateral damage. The other 2 compressors seem un-damaged.

My concern is that if light load & compressor short cycling has caused the compressor failure, the best solution may not be to repair/remanufacture the current compressor but replace it with a smaller compressor specified to cope with the minimum load.

Please could you let me know if it is possible to have a refrigerant pack with different sizes of compressors or if they should all be the same size?

I am confident with the controls side of it & re-programming the controller. I am also confident doing the mechanical work of changing the pipe-work & oil scavenging system etc. I just have no experience of packs with unequal parallel compressors and I am unsure if there are factors to take into account that I am unaware of.

Any comments would be appreciated . . .