COMBINATION HIGH LIMIT/LOW LIMIT-CIRCULATOR SWITCHING RELAY CONTROL Replacement for the Control of Hot Water Systems Where Boiler also Provides Domestic Hot Water • Clearly marked terminal panel for thermostat, circulator and burner circuits. • Knockouts top and bottom — Plenty of wiring room. • Can be used on systems zoned with circulators or water valves. • Maintains low limit temperature for domestic hot water.