Installing a Goodman Piston Coil (CAPFA Series): Verifying Correct Piston Sizing

When installing a Goodman CAPFA series piston coil, it is critical to ensure the piston size matches the indoor and outdoor equipment combination. Using the correct piston ensures proper refrigerant flow and system performance.

Locating the Piston

The factory-installed piston is housed inside the piston distributor assembly, which is located behind the front plate of the coil. It may be difficult to view from the top due to its recessed position.

To identify the installed piston size:

• Locate the brass nut that secures the liquid line copper stub to the distributor assembly.

• The piston size is typically stamped on the brass nut for easy reference.

Verifying the Correct Piston

Before proceeding with the installation:

1. Identify the model numbers of both the indoor coil and the outdoor condenser.

2. Reference the official Goodman piston chart to verify the correct piston size for the equipment matchup.

   • The piston chart will list the required piston size based on indoor and outdoor unit compatibility.

3. If the piston in the coil does not match the required size, replace it with the correct one before completing the installation.

Final Step

Once the correct piston is confirmed and installed, proceed with the rest of the coil installation following standard procedures.