Is an expansion tank necessary for a small radiant system?
A. Yes, an expansion tank is required for all hydronic radiant heat systems. Expansion tank size is determined by heat source size. We carry five models: Basic tanks: HRMVSEX15, HRMVSEX30, Tanks with auto fill valves: HRMVSFT109, HRMVSFT110 and HRMVSFT111. The auto-fill valves on the HRMVSFT109, HRMVSFT110 and HRMVSFT11expansion tanks work GREAT for closed radiant systems. The auto-fill valve is the easiest way to fill the system with water AND keep it full (otherwise, you’ll need to use a hose and connect to the fill-valve on the manifold which usually sprays water everywhere).
