always calculate the bypass requirements based on the difference between the total system CFM and the smallest zone's CFM

What are the symptoms of a failing Berko heater motor

The 138-18-021-01 white spring is designed for a specific outlet pressure range of 1 to 5 PSI

3-pole footprints

provided the thermostat footprint fits within the internal dimensions of 4-1/4" H x 3-1/2" W x 1-5/8" D

Spirax-Sarco 58128 Gasket Freon always calculate the bypass requirementsThe Spirax Sarco 58128 is an industrial grade 2" replacement gasket specifically engineered for high performance sealing in FA series and FT series float and thermostatic steam traps. This graphite cover gasket is critical for restoring system integrity during scheduled maintenance or rebuilds of 2 inch Spirax Sarco FT 15, FT 125, FA 30, and FA 150 units. Designed to withstand the thermal cycling and high pressure demands of localized heating and