Circulator Pump Setting

[shakedownstreet]

Hi there. My name is Vinny and I live in upstate NY. I have a 100 years old cape about 1300 square feet. I have a question about my circulator pump. A contractor said I should have it at its lowest speed because the hot water will stay in the baseboards longer, retaing more heat there, and making my house warmer longer. He said that on its highest speed, it zooms through taking a lot of the heat away quicker.

I have a Weil Mclean gas hot water boiler thats about 30 yrs old with baseboards. 2 zones(one for downstairs, one for up), a digital thermostat, all replacement windows, doors, blown in cellulose in walls, and energy saving window treatments. My friend said I am building a Fort but I am into effeciency and want to be snug in my house. Any suggestions? Im all ears. Thanks

[Bob NH]

The contractor is incompetent in the field of heat transfer.

The rate of heat transfer is increased by the velocity of the water in the pipe. I won't try to explain all of the formulas.

The rate of heat transfer is also greater when the water temperature is greater. Since higher flow will more quickly renew the hot water in the pipes, higher velocity will result in higher temperature in the pipe.

The higher velocity also increases the rate of heat transfer in the boiler, and therefore increases the efficiency of the boiler.

Higher flow and velocity are better as long as the velocity is not so high that it causes erosion in the pipes.

[shakedownstreet]

Hey Bob. Thanks a lot for the post. I have to say, being a novice and all, I do notice a change since I turned the setting to its lowest. I hear the boiler more, feel less heat from my baseboards, and my house warms up a lot slower. The formulas would be really interesting to know but I dont think Im there yet! I do understand your post though and appreciete the concepts you conveyed. I am going to my basement after I hit send.