Did You Know the operation of the Regulating Valve is to maintain the correct discharge pressure on water cooled units?

This is preformed by regulating the flow of water through the condenser to remove the heat from the refrigerant. If the water temperature is too cold, the refrigerant discharge pressure will be too low that could cause the evaporator coil to freeze, low suction pressure nuisance trips, or poor oil return to the compressor.

There are two basic types of valves that are used in our industry. There is a two and three way valve configurations. The two way would be for complete shutoff of the water when the unit shuts down. The three way is used to divert the water and maintain flow to the condenser water loop when the valve is closed off to the condenser coil. These valves are normally installed on the leaving side of the condenser coil to maintain a full column of liquid in the condenser.

When checking the operation of the valve and the unit is operating with a high discharge pressure, it is important to check the condenser water and refrigerant temperatures entering and leaving the coil. The valve spring pressure can be decreased to allow the valve to be opened farther and increase the flow of water. The valve can be opened manually by releasing the spring pressure and using two screw drivers, prying up against the bottom of the spring to increase the upward movement of the valve stem. When the water leaving the condenser is too hot, it indicates that there is not enough water flow. This can be caused by the strainer or condenser openings being plugged with sediment, the circulating loop pump failure, condenser supply water too hot, or regulating valve failure. If the leaving water is cold and the refrigerant liquid line is hot, it is possible that the condenser is fouled and needs to be acid cleaned.

It is important to diagnose the condenser to verify valve is operating correctly. The regulating valves have been known to seize and stop the movement of the valve stem. Also it is important to check the bellows at the time of a refrigerant leak test. They can develop cracks and leak refrigerant. These valves can be rebuilt with replacement parts. Also it is best to cycle the unit several times to verify the operation of the regulating valve after adjustment has been made to the valve. This will insure that the valve holds to the correct pressure setting and operation is correct.