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The GOODMAN b1789870 is a flow check piston kit designed for use in refrigerant metering applications within split-system heat pumps and air conditioning systems. The kit includes a 0.070-inch orifice piston that replaces or supplements a piston-style metering device, controlling refrigerant flow between the indoor and outdoor coil sections. At 0.017 pounds, this is a small but precise component that directly affects system efficiency and refrigerant distribution. Installation is typically performed by a licensed HVAC technician during a system conversion, refrigerant circuit service, or seasonal metering device swap.
This piston kit is used in residential and light commercial split-system HVAC equipment where piston-type metering devices are employed instead of TXV expansion valves. The 0.070-inch orifice size is a fixed-bore specification, meaning it is matched to a defined system capacity and refrigerant type. Technicians select the correct orifice size based on the equipment manufacturer's metering chart for the specific indoor and outdoor unit combination being serviced.
Designed as an OEM-style replacement piston for residential and light commercial split-system heat pumps and air conditioners that use fixed-bore piston metering devices. Consult the equipment manufacturer's orifice selection chart to confirm the 0.070-inch orifice size is appropriate for the specific indoor and outdoor unit combination before installation.
This component is installed by a licensed HVAC technician. Recover all system refrigerant in accordance with EPA Section 608 regulations before opening the refrigerant circuit. The metering device piston is typically located in the piston assembly housing at the indoor coil or in the liquid line connection. Confirm the correct orifice size against the manufacturer's metering chart before installing, as an incorrect piston size will directly impact system capacity and efficiency.
We pulled together the parts most installs need for this unit, plus a few add-ons worth a look. Check what you need — nothing here blocks checkout.
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