Did you know that Rawal valves can help fix humidity issues?

For this solution to be successful, you will need to REDUCE the system airflow in addition to installing the Rawal valve. 

Lowering system airflow does TWO things:

  1. It lowers the evaporator temperature, which allows the evaporator coil to remove more moisture
  2. It reduces sensible capacity which lengthens run time, which will remove more moisture 


  1. A colder evaporator temperature also means a colder leaving air temperature, which means you could possibly run into ductwork or supply register condensation (caused by components being colder than the dew point)
  2. Reducing capacity may prevent you from satisfying the dry bulb temperature on design days  
  3. Design Note: verify proper oil return when condensing unit is above the evaporator (the Rawal bypasses hot gas around the compressor, which means there is less refrigerant headed back to the compressor from the evaporator, which in turn could lead to oil return problems). To avoid an issue here, have your cfm sales engineer or territory manager verify the size of valve and you won’t have any oil return issues!

Are you working on any projects that we can help with?

Please call cfm for design assistance today at 816-842-5400!

Brad Telker
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