this unit is the standard for restoring factory-spec operational efficiency and combustion stability in the field

Installation is streamlined via the 16-gauge steel base plate

Common Installation & Compatibility Questions Is the HC21ZE121 interchangeable with the HC21ZE121A

or internal control failures

Optimized Airflow Control: 3-speed functionality provides 1075 RPM high-speed performance with lower taps for dehumidification or silent heating cycles

Conbraco 4A00510 Internal Kit Freon this unit is the standardThe Conbraco 4A00510 Internal Kit is a comprehensive field service solution specifically engineered for the 1" Apollo RP4A and RPLF4A series reduced pressure zone (RPZ) backflow preventers. This genuine OEM Apollo Conbraco rebuild kit includes all necessary components to overhaul both the first and second check assemblies and the relief valve module in a single maintenance cycle. Featuring high grade lead free components, the 1 inch internal assembly