Circulating pumps always on

gordonp1 · Oct 15, 2010

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.

peter_ · Oct 16, 2010

I believe your contractor is right. Replacing pump every few months will be even more expensive, just consider the cost of pump itself, which is $70-250. For example, Taco pumps http://www.pexuniverse.com/store/manufacturers/taco or Grundfos http://www.pexuniverse.com/store/manufacturers/grundfos .

Do you have any filters or strainers installed in your system?

Sponsor · 2022-01-29T12:20:58-0800

Thatguy · Oct 16, 2010

gordonp1 said:
dirty water and particles

Speaking of financial tradeoffs, how much to clean and maintain cleanliness?

Are those pumps rated for continuous duty?

gordonp1 · Oct 16, 2010

They are rated for continous duty. I do not have any filter or strainers installed. The old boiler pump ran without any problems for 17 years with a boiler that was about 40 years old.
We have been in this house for 17 years and no problem with the pump being off when there is no heat demand. I don't mind if the new pumps are on during the heating season but to keep them running from March to October?
Where can I find information about installing a filter or strainer?

Thatguy · Oct 16, 2010

Apparently seasonal startups are a problem, which they try to overcome with high starting torque, but they don't say the cause of this problem.
http://www.bellgossett.com/productpages/parts-nrf-22.asp
Maybe all pumps with clean or dirty water have this problem. Something must seize up.

I guess another fix would be to periodically run the pump with some kind of timer, say 1 minute on once per day or per week, regardless of water demand.

One or both pumps failing would cost how much? More than $240 each year?

David_Griffin · Feb 27, 2011

gordonp1 said:
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.

He was not right. Pump must run only over certain temperature because if the water is cooler then this water steals heat. Your pumps not only heating your house but mostly cooling rooms. Pumps should stop if no heat demand from the furnace.

Circulating pumps always on

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