Condenser Fan: Description and Operation

Cooling Fan Control






The radiator and condenser cooling fans are controlled by both radiator coolant temperature and air conditioning retrigerant pressure. The fans are controlled depending on the cooling air flow requirement. At lower coolant temperature / refrigerant pressure, both fans operate at low speed (in series); at verv high coolant temperature / refrigerant pressure, both fans operate at high speed (in parallel).

Fan speed switching is accomplished through a fan control relay module. The radiator thermostatic switch has two sets of contacts - one for slow speed fan drive and one for high speed fan drive. The refrigerant triple pressure switch contains a pressure contact set for high speed fan drive. A separate refrigerant single pressure switch is used for low speed fan drive.


Low speed fan operation

Both fans run at low speed (in series) when the radiator coolant temperature reaches 187° F (86° C) and / or the refrigerant pressure reaches 174 psi (12 bar).


High speed fan operation

Both fans run at high speed (in parallel) when the radiator coolant temperature reaches 212° F (100° C) and / or the refrigerant pressure reaches 290 psi (20 bar).