Retrozone offers 2 different sizes of tubing to connect Solenoid Panel and Pump to the Flexdampers.
The following rules apply:
FR-12 (120 feet) and FR-25 (250 feet)
3/8 OD tubing: Can be used when daisy chained or home run, or any combination of both. Available only in black. Must be home run when Flexdampers and Tubing will be inaccessible after installation due to sheet rock or other construction (not recommended, but cannot be avoided in many situations) for future service. May be used for Daisy chaining if dampers and tubing will be accessible in the future.
1/4 OD tubing: Can be only home run, only one damper per run. Available in black and three colors. Must be home run when Flexdampers and Tubing will be inaccessible after installation due to sheet rock or other construction (not recommended, but cannot be avoided in many situations) for future service. Available in black and three colors for ease of installation. While not mandatory, if possible order 3/8 to 1/4 T or manifold connectors to use at solenoid panel to reduce air restriction, OR loop 1/4 OD tubing back to zone output tubing on SPP panel. FRS 1/4 od tubing is less expensive and easier to handle on home run jobs, but will only handle one Flexdamper per zone.
5 feet only of FR 3/8 tubing. Use when manifolding home-run FRS 1/4 OD tubing together at SPP panel to provide less air resistance from panel to 1/4 OD zone tubes. Optional. Use with 3/8 to 1/4 reducing T’s and manifolds above.
When 1/4 of only tubing is used, be sure to install or include 3/8 to 1/4 barbed fittings in SPP zone outlets.
Ten foot piece of 3/8 OD tubing used for making manifolds with 3/8 to 1/4 union connectors.