Goodman b1789851 Flow Check Piston Kit 0.051 in Orifice

Product Description

The GOODMAN b1789851 is a flow check piston kit designed to regulate refrigerant flow in split-system heat pump and air conditioning equipment. The kit includes a 0.051-inch orifice piston that meters liquid refrigerant entering the indoor coil, controlling the expansion process during both cooling and heating cycles. This type of piston-style metering device is a fixed-orifice component, meaning flow rate is set by the orifice diameter rather than a variable element. HVAC technicians install or replace these pistons during system commissioning, refrigerant circuit servicing, or when converting a system to a different capacity configuration. The unit measures 0.5 inches in height and 15/32 inches in width, and weighs 0.017 pounds.

Flow check piston kits are used in residential and light-commercial split systems where a piston-type metering device serves as the primary refrigerant expansion component. The 0.051-inch orifice size corresponds to a specific system capacity and refrigerant type pairing. Technicians select the correct piston diameter based on the outdoor unit capacity and the refrigerant in use. This kit is classified as an accessory and conversion component, making it applicable during system changeouts, coil replacements, or refrigerant conversions where the existing orifice size must be updated to match the new equipment configuration.

Key Features

• 0.051-inch orifice diameter for precise refrigerant metering
• Fixed-orifice piston design — no moving parts to wear or fail
• Compact form factor: 0.5 inches tall, 15/32 inches wide
• Lightweight at 0.017 pounds for easy handling during installation
• Manufactured in the United States
• Classified for use as a conversion kit and orifice replacement component

Compatibility

Designed as an OEM-style replacement piston for GOODMAN split-system heat pump and air conditioning equipment requiring a 0.051-inch flow check piston. Verify orifice size against the equipment nameplate and manufacturer specifications before installation.

Installation Notes

Installation and replacement of flow check pistons should be performed by a licensed HVAC technician familiar with refrigerant circuit work. Recover all refrigerant and relieve system pressure before opening any refrigerant lines or the piston housing. Confirm the replacement orifice diameter matches the outdoor unit capacity and refrigerant type per the equipment documentation. Follow all applicable EPA Section 608 regulations when handling refrigerants during this service procedure.

Technical Specifications

• Orifice Diameter: 0.051 inches
• Unit Height: 0.5 inches
• Unit Width: 15/32 inches
• Unit Weight: 0.017 pounds
• Country of Origin: United States
• Product Class: Conversion Kits and Orifices
• Vendor Part Number: 119F3169

Standard Information

• Brand: GOODMAN
• Manufacturer Part Number: b1789851