A hypothethical question regarding sizing circulators

steamfitter

Does static head directly affect the sizing of a circulator in a hot water heating system?
If I have two identical hw sysytems with the same heat loss calculation, design the same hw heating system, with the same amount of piping, heat emitters, etc. with the only difference being that one space is vertical and the other is horizontal, would the circulators be identical?
Or would the vertical system need to be larger to accommodate the higher static head pressure?
As I try to understand the readings of hydronics, I am inclined to believe that both systems have the same friction loss/pressure drop. Therefore, the circulators should be identical. Am I missing anything?
Thank you in advance for your your input!

Gordy

You are correct both circulators would be identical in your example. Static head does not play a role in a "closed" heating system. Think of a Ferris wheel .

Snowmelt

gordy is right the Ferris real theory

hot_rod

steamfitter said:

Does static head directly affect the sizing of a circulator in a hot water heating system?
If I have two identical hw sysytems with the same heat loss calculation, design the same hw heating system, with the same amount of piping, heat emitters, etc. with the only difference being that one space is vertical and the other is horizontal, would the circulators be identical?
Or would the vertical system need to be larger to accommodate the higher static head pressure?
As I try to understand the readings of hydronics, I am inclined to believe that both systems have the same friction loss/pressure drop. Therefore, the circulators should be identical. Am I missing anything?
Thank you in advance for your your input!

That is a very common misunderstanding in closed loop hydronics.

Here is a good explanation on how to "see" it.

Idronics 12 is an excellent read for newbies and experts, there is always something to brush up on in hydronics. This is my handout at every class I teach now, regardless of the training request. It should be at every suppliers counter

http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_12.pdf

Ironman

It is the job of the fill valve to introduce enough pressure into the lines to overcome the static head (gravity). The circulator only has to overcome dynamic head (friction). This is why the static fill pressure must be increased proportionate to the elevation.

steamfitter

Thank you!
Appreciate you adding the role of the prv.

steamfitter

Thanks, hot rod for the info!
Idronics is awesome!
Also, thank you guys for the ferris wheel picture. A classic from Dan's Classic Hydronics. I remember the idea, but was just having some bad case of the second thoughts.

Paul48

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