Here's a simple, 12 volt ON / OFF Heater Valve operated by a solenoid.

15mm Inlet and Outlet.

1/4" male spade terminals.

Inlet has gauze filter.

Size 104mm inlet to outlet x 69mm high x 42mm wide.

Normally closed valve.

Opens when 12v applied. 

NOTE: This valve will not regulate the water flow. It is just ON or OFF.

SOLENOID OPERATED ON/OFF HEATER VALVE 15mm (5/8") #HVSOL