Refrigerator system control valves
Refrigerator Troubleshooting – Fusible plugs
Note: Before charging a system with a new or replacement refrigerant check the fusible plug rating.
Condensers and receivers are fitted with fusible plugs. These are safety devices against excessive high side pressures developing in the event of a fire. (Excessive operating pressures are controlled by the high pressure cut-out switch) The plugs are normally brass [...]
Refrigerator Troubleshooting – Reversing valve
This type of valve is in common use for hot gas defrost systems and room air conditioners. It effectively reverses the flow of refrigerant to the evaporator and condenser when a defrost period is initiated. In room air conditioners, it reverses the flow when heating is required rather than cooling.
The valve is an electromagnetic type [...]
Refrigerator Troubleshooting – Water regulating valve
The pressure operated type is the most popular. It is employed in water cooled systems to control the flow rate through the condenser, modulating in response to changes in the condensing or operating head pressure.
It is designed to stop the flow of water to the condenser when the plant is at rest. An increase in [...]
Refrigerator Troubleshooting – Evaporator pressure regulator
This valve is fitted in the suction line to control the pressure in the evaporator, to prevent it dropping below a predetermined pressure. It is used to control the evaporating temperatures of systems such as drinking water fountains and beverage coolers, to maintain a constant evaporator pressure/temperature and prevent freezing.
It is also used in multi-evaporator [...]
Refrigerator Troubleshooting – Crankcase pressure regulator
As a compressor starts, a heavy load is imposed on the drive motor. The crankcase pressure will be at its highest against normal or abnormal loading.
The function of the regulator is to keep the pressure in the crankcase to a reasonable level to protect the motor from overload. This applies when the evaporator pressure is [...]