How to Measure Head

Mark Mathys

I am trying to select a circulator pump for my hydronic heating system and am not sure how to measure "head". It is a 3 story house with a basement. The boiler is in the basement and right now the radiators on the 3rd floor are disconnected but will be reconnected in the future. I was thinking about a Taco 0011 pump.

And advice will be appreciated.

Mark

jerry scharf_2

Mark,

In a closed, pressuried water system (that's what you have) the circulators don't "lift" the water to the third floor. The pressure in the system does that. The head of the pump is used to overcome the drag on the water moving through the pipes.

It takes a clear understanding of the piping design and controls before this can be answered. Getting the wrong pump can seriously impact the functioning of the system. You may be better off getting an experienced person to size the pump and look over the system. A Taco 011 is a large pump for the average system.

best of luck, jerry

Wayco Wayne_2

Hey Mark

Jerry's right. A 011 Taco is probably big for your installation. I have a rule of thumb I use. "Measure the longest run in feet. Allow 6 feet of pump head per 100 feet. I would use a Grundfos 15-58 circulator. It has 3 speeds. After the system is up and running you could measure the temperature difference between the water leaving the boiler and the water coming back. Most systems are designed for a 20 degree difference. You could change speeds and find which one gets you closest. Good Luck WW

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Mark Mathys

I should mention that this is an old gravity feed system that has big pipes. After each radiator they drop down a size. I am installing a second boiler using primary-secondary piping. Previously the system used a Taco 007 for the whole system. I am using 2 of these pumps (1 for each boiler). I just talked to the guy at the plumbing shop and he said the same thing both of you said, basically the 0011 is probably too big. I do have another 007 that I will probably try in the primary circuit although the 3 speed pump sounds like it might be a good idea.

Thanks
Mark

PS the boilers are 160,000 and 150,000 btu.

Steamhead

Sizing your system circulator

on a gravity conversion is different from more-modern systems, because the pipes are large and offer so little resistance to the flow of water.

The info you need is right here-

http://www.heatinghelp.com/newsletter.cfm?Id=125

It pays to wander off the Wall.

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Brad White_2

The Grundfos 15-58

is very forgiving. Nice pump and you will like the color probably. Wayne is right.