Is there any adjustment required for the liquid injection valve of the APR Control?

No, YOU WILL NEVER NEED TO ADJUST THE INJECTION VALVE. If you believe there is any need to adjust the liquid injection valve, reach out to our team.

Adjusting the liquid injection valve without consultation with Rawal Devices Senior Technical Engineer will void warranty.

Please call Rawal Devices Engineer’s (800-727-6447) prior to attempting any adjustment!

Will I need to adjust the APR Control?

The APR Control is shipped from the Factory set for approximately 40 degrees F. evaporator coil temperature, or to start opening at 118psi (in an R-410A system). We have found this to be an excellent setpoint for most applications, and will not require adjusting the APR Control.

However, every job, system, and application is unique. Our rule of thumb is to allow the APR Control to provide maximum modulation before compressor termination. If the runtime is inadequate or low load operation does not cause suction pressure to fall low enough, you may need to adjust the APR Control Compressor Ratio Reduction Valve (CRR Valve).

Please call Rawal Devices Engineer’s (800-727-6447) at the factory prior to attempting any adjustment. For more information see our Installation page:

I have installed the APR Control; now what are the steps?

Charging Unit after APR Control Installation.

After properly installing an APR Control a unit should be charged to the factory recommended specifications, the installation of the APR Control does not require additional refrigerant. During the charging process in order to maintain accurate pressure readings the manual shut off valves at the APR Control connection points should remain closed, this will prevent the APR Control from attempting to modulate during the charging process.

Start-up Procedure

With the manual shut off valves at the APR Control connections closed, follow equipment manufacturer’s start up procedures to ensure the unit is operating properly. Once it is determined the unit is operating properly, open the manual shut off valves to bring the APR Control into the circuit.

In order to test operation of the APR Control there must be a reduction in suction pressure. To simulate this process restrict the airflow across the evaporator coil just enough to lower the suction pressure below the desired suction pressure setpoint of the APR Control. At this point the APR Control will attempt to stabilize the suction pressure. For more information see our Installation page: