Choosing the Right Hot Water Circulator

Finees M. Casado

Hi, I just finished my basement and I installed hot water baseboards, the way I have the whole house uptairs. I added a heating zone for the basement with its thermostat. When I turn up the thermostat the circulator turns on but I do not get much pressure on the return. I bought a Taco circulator 1/25 HP. I think it's too small for the feet of copper I installed in the basement, considering the pipes go up and down the baseboards in the basement. For this zone, I used approximately 220 feet of 3/4 inch copper line. I need help choosing the right size circulator. Your help is deeply appreciated.

Steamhead (in transit)

That's a lot of pipe

is your present circulator the model 007? Is your problem that the heat does not reach the ends of the zone?

Finees M. Casado

Problem with the Circulator

Hi, yes the circulator is model 007 and the heat does not reach the end!
Thanks
Finees

Finees M. Casado

Circulator Problem!!

Hi, yes the circulator is model 007 and the heat does not reach the end! Do I have to split the loop like the diagram on this website or get a bigger circulator? http://www.heatinghelp.com/heating_howcome4.cfm

Thanks Finees

Finees M. Casado

Additional Question!

> is your present circulator the model 007? Is your

> problem that the heat does not reach the ends of

> the zone?

Finees M. Casado

Additional Question!

Steamhead, isn't true that the boiler will not turn on automatically if the heat does not reach the end of the zone? Because my understanding of this, is that the circulator shall be powerful enough to inject the water into boiler water chamber and then when the water temperature lowers to a certain degree then the boiler turns on to heat it. I think that's the principle isn't?
Thanks
Finees

Joe Mattiello

We need to kmow the BTU load

Sizing a pump is based on load, and system resistance. You can calculate load, by adding the btu output of the baseboards on each zone. GPM required, is 1 gpm, per 10,000 btu output, based on a 20 degree delta T. The system resistance is calculated by adding the lineal footage of pipe, elbows, and valves. Once we have accumulated this information, we can refer to a frictional loss chart, for the pressure drop of the system, when pumping X amount of flow through the system, to satisfy the load. 220 lineal ft 3/4" pipe is not significant if the load is approx 30,000 btu's. Assuming another 50% of piping for valves, and elbows = 330ft X 2.5 ft per hundred ft = 8.25Ft. The 007 will deliver approx 4 gpm @ 8 ft. Please advise, if you have any questions or concerns.

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

Steamhead (in transit)

If the boiler is maintaining temperature all the time

or has shut off on high limit, and the circulator is not moving enough water, the burner won't restart for a while.

But if the boiler is cold while your 007 is running and the burner doesn't start, but it starts when one of the other zones calls for heat, you have a control problem.

Maybe it's time to get a few more eyes on this thing. Have you tried the Find a Professional page of this site?

Finees M. Casado

Purging the Loop!

Joe, thanks very much. The 007 was excellent for my 220 feet of copper (38 linear feet of baseboards). I took your advice and I purged the system. I learned how to purge the system correctly from this website as well. The loop (zone) is running perfectly. (The loop was full of air)

Thanks
Finees

Finees M. Casado

Hi Steamhead,
It's all taken care of, the system needed to be purged. That's why the loop water was cold on the return.
Thanks
Finees