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bradwhitehorn
19-10-2014, 03:04 PM
Hi Guys,

Just looking for a bit help understanding as how to a freezer and chiller runs of the same unit? I kinda have a rough idea that the pressures are controlled by CPR and EPR on this type of system. Just need it explained it a bit clearer.

Cheers

Rob White
19-10-2014, 04:28 PM
.

The compressor and condenser need to be big enough to
run both evaporators. The system is then designed to run
at the lowest pressure (freezer) and the pressure is controlled
inside the fridge with an EPR (evaporator pressure regulator).

The EPR holds the pressure back inside the fridge evap and the
freezer pressure is at suction pressure. With this set up, to
protect the compressor you put a CPR (crankcase pressure regulator)
in the suction. This stops the suction pressure getting too
high in the event of a start-up, defrost or something else that
might cause the suction pressure to rise.

Rob

.

Glenn Moore
20-10-2014, 12:22 AM
Just one further point to add to Robs, is that you must fit non return valves to the suction outlets from the freezer evaps otherwise gas from the chiller evaps can condense in the colder freezer evaps during their off cycle,