Maneurop Compressor shaking on start up

[Robert88]

Has anyone had problems with new single phase maneurop compressors (MTZ28). I have had a few that shake on start up and pull around 44amps before either starting or blowing the circuit breaker or the capacitor. At other times the same compressor has started with no problems. Not sure what to do other than change the brand of compressor which then works fine on the system. Any easy solution???
Thanks

[stufus]

Flooding in off cycle. crankcase heater duff or if part of a tandem or multiple no nrv on discharge.
Or maybe none of the above, but it's obviously strugling to get away,could be jumping the springs but would expect it every time.
Cheers
Stu

[DRISCOLLS]

How are the electrics, relay, caps etc,might be worth putting new on.

Flooding in off cycle. crankcase heater duff or if part of a tandem or multiple no nrv on discharge.
Or maybe none of the above, but it's obviously strugling to get away,could be jumping the springs but would expect it every time.
Cheers
Stu

[THE DUDE]

Im assuming the Voltage and start componets are good. Will it start with the Suction and Discharge pressures Equalized?

[Robert88]

Does the same when the pressures are equallised. It is running off a 2.5mm lead with a 10amp plug. Do you think this could cause the problem?

[mikeref]

What is the length of your 2.5mm lead?
What is the compressor running amps...as stated on it's specifications label.
Use a Fluke, or similar meter to do a minimum/ maximum voltage logging to see what the volts drops to during start up.

[B G Scott]

Has anyone had problems with new single phase maneurop compressors (MTZ28). I have had a few that shake on start up and pull around 44amps before either starting or blowing the circuit breaker or the capacitor. At other times the same compressor has started with no problems. Not sure what to do other than change the brand of compressor which then works fine on the system. Any easy solution???
Thanks

Is this a new installation or a retro-fit?

[Robert88]

Is this a new installation or a retro-fit?

It is a retro-fit

[mikeref]

Does the same when the pressures are equallised. It is running off a 2.5mm lead with a 10amp plug. Do you think this could cause the problem?

Suspect low voltage on start up...Had a chance to do that minimum voltage test yet? (Post #6)

[B G Scott]

It is a retro-fit

First check that the compressor is operating within the design parameters as set out in the selection data provided by the manufacturer.
As this is already fitted put your amp probe on the supply cable, wind in the suction service valve and start the unit, observe the current drawn and slowly open up the suction service valve and see if you get a smooth start and a current draw in line with the published data.
If you do consider installing a crank case protection valve in the suction line to limit the suction pressure during pull down to within the limits as detailed in the data sheet.
When installed check the current drawn on start up and set the valve opening to keep the amps within the tolerance levels indicated by the data sheet.