High exhaust back pressure will result

1、If the head pressure is too high,（）

If the head pressure is too high,（）Athe relief valve should open before the high-pressure cutoutBthe relief valve should open and let excess ...

2、Which will cause the high pressure cut

Which will cause the high pressure cutout to stop the compressor in a R-22 system?（）ACondenser leakageBA shortage of liquid refrigerantCExcessive frost on the evaporatorDNot enough condenser cooling water

3、For a L√Opurifier, if the back pressur

For a L√Opurifier, if the back pressure of the oil outlet is too high, the interface between oil and water in the bowl will （）.Abe interruptedBmove downwardsCmove outwardsDretain original positio

4、High firing pressures and a low exhaus

High firing pressures and a low exhaust temperature in a diesel engine may result from （）.Adecreased piston to cylinder head clearanceBincreased exhaust system back pressureCearly fuel injection timingDlow scavenge air temperature

5、（）uses one or two high pressure pumps

（）uses one or two high pressure pumps for all the cylinders with one more standby, while（）have a separate high-pressure pump for each cylin...

6、One cause of high head pressure occurr

One cause of high head pressure occurring in a refrigeration system can be （）.Ainsufficient cooling water flow to the condenserBa low refrigerant charge in the systemCthe liquid valve is open too muchDhigh evaporator superheat