Heat Pump Charging Won’t Be Difficult Anymore

Charging A heat pump

An auxiliary heating system works to prevent the home from getting cold when the heat pump is taken off-line to repair it. In cold weather, charging heat pumps is a tough process as there is a little latent heat load around the evaporator in the system. The refrigerant load of the heat pump is not perfect, but the levels are close and efficient. If charging your heat pump or AC is difficult for you, read these tips from professional heat and air specialists in Shawnee, OK.

Charging Your Heat Pump

  • A plastic sheet is used to block the condenser and prevent air from leaving the system.

  • Through a 4-way reversing valve, the heat pump is set to cool mode. The low voltage wire is to be removed forcing the heat pump to operate in refrigeration mode even if the thermostat demands heat, which is supplied by the auxiliary heating system.

  • From the refrigerant lines that contain refrigerant vapor, air is bled.

  • The valves are shut down when the liquid refrigerant stops flowing, and the cylinders are placed in a tap water bucket. It keeps the cylinders temperate to maintain pressure as refrigerant vapor is charged into the thermal pump–cylindrical pressure can decrease quickly while refrigerant vapor is being charged.

  • The valves shut down, and the cylinders are placed in a bucket of tap water when the coolant liquid stops flowing. This keeps the temperature of the cylinder to a temperature appropriate for maintaining pressure while charging refrigerant vapors to the heat pump. During charging, the cylinder pressure can quickly drop.


A modern heat pump
  • The pump's superheat is measured. The fluid temp of the coolant in the evaporator is measured via the suction gauge and the temperature of the coolant from the evaporator.

  • The pressure of the head and suction line is monitored and comparable to the overheat of the system to determine an accurate charge.

  • The plastic sheeting from the condenser is removed and the low volume orange wire replaced with a heat pump switch to the heating system after the system has been charged.

  • For normal operating conditions, the gauges of the system are monitored.

When charging heat pumps in cold weather, heat and air technicians use the super-heat procedure. Because of the size of the free spool compared to the indoor spindle, the system reactivity of the heat pump in heating mode is reduced when it is attempting to charge. In outside temperatures of 20°F, the superheat method has ensured the correct refrigerant charging.

We, Comfort Control Specialist, a heat and air company in Shawnee, OK offer a range of available resources to help you understand and resolve your system from your source of information on HVAC repairs. Call us at any time and get more information.