
Originally Posted by
fly300kts
No,
If no Freon, the clutch will not engage because the low pressure switch will prevent to do so.
With AC OFF, if you hear noise from the compressor, it means that the compressor clutch is going bad. You can always replace the clutch itself but a PITA. You better replace the entire unit.
At the same time, replace the dryer
Phil
Ok Thanks Phil. That's exactly what I was thinking, but the problem is that Benthley manual says that these kind of compressor has not clutch and that we should avoid to run the engine over 2500RPM when the system is empty. So, I am a little bit confused...See pasting below from benthley manual:
The compressor is always driven (by pulley or via drive shaft by engine); there is no A/C clutch.
The compressor is equipped with an "internal oil circuit" to prevent damage if the refrigerant circuit is empty. This internal lubrication is only possible if there is still a residual quantity of refrigerant oil in the compressor.
The engine must not be started unless the refrigerant circuit has been properly assembled. If, for example, the refrigerant lines have not been connected to the compressor, heat generation inside the compressor with the engine running may lead to destruction of the compressor.
The A/C Compressor Regulator Valve N280 is not activated if the refrigerant circuit is empty and the compressor runs at idle with the engine. However, as there is no refrigerant available, the refrigerant oil required for compressor lubrication is not conveyed. Compressor lubrication is maintained by way of an "internal oil circuit" to prevent damage.
If the engine has to be started when the refrigerant circuit is empty:
- Refrigerant circuit must have been fully assembled.
- Compressor must contain at least a quarter of the amount of refrigerant oil specified for this refrigerant circuit.
- Engine speed must not exceed 2500 RPM.
- Engine should not be left running for longer than is absolutely necessary.
Dave.
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