I just got a new boiler installed (Laars Mini-Therm II 160) with two circulating pumps. The plumber wired the pumps to be always on. My old system would turn on the pump only when heat was demanded. The plumber claims that because I have an old system with dirty water and particles, the pumps would be damaged if they are off for a long time. I have two B&G NRF-22 pumps that use together 194 watts - that translates into about $240/year just to run these pumps. It just does not make sense to me. Is he right? I would like to tell him to rewire it so that the pumps start when thermostat turns on.