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chass1971
26-06-2007, 12:35 AM
could somebody give me a hint?
I need to replace a bad compressor , copeland model # MRH4-0760-TFC-505 R22 7.5 hp 208/230 volts 3ph, I called the supply house and they told me that I could replace it with a copeland BRE4-0750-TFC or ZR94KC-TF5 both of these compressors are 7.5 hp 208/230volts 60hz 3ph but both are for air conditioning then I called the manufacturer of the compressor, they told me that I could use ZB50KQ-TF5-551, my question is, can I use the BRE4... or the ZR94KC... instead???
Its for a cold storage room I need to keep a 2-4 centigrades inside.
thanks...

US Iceman
26-06-2007, 12:53 AM
Let me see if I understand this. You have a low temperature 7.5 HP compressor operating on 208/230 volts that is bad.

The manufacturer said to use a different model number, which I am assuming is a low temperature 7.5 HP compressor for operation on a 208/230 power supply.

Your supply house says to use a completely different model number that is for an air conditioning application, but happens to be a 7.5 HP compressor for operation on a 208/230 volt power supply.:eek:

You cannot compare the motor HP to capacity. The air conditioning compressor will probably have a different displacement (less cubic feet per hour) than the refrigeration compressor.

If you want to keep the same capacity for cooling you need to use the correct compressor for the job.

monkey spanners
26-06-2007, 09:17 PM
I think the differance between the ZR and ZB scrolls is that the ZB is rated for R404a also. The following numbers, 94 and 50 is the btu rating. ZR is rated at 7.2c evap and 54.5c cond. Don't know at what temps ZB's are rated but its a lower evap temp hence the lower number for the same motor power. I have run both ZR (R22) and ZB (R404a) scrolls on DX milk tanks and icebuilders.
You will also need a crankcase heater as they are not supplied with the compressors (in the uk anyway)
I'd go with the manufacturers recomendations, after all they should know.

Cheers Jon