Circulation pump

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Circulation pump

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redcuckoo

Hi,

Just a quick question....... When looking at different circulation pumps what does the sizes mean regarding 4m, 6m & 8m head???

Thanks.
 
redcuckoo said:
Hi,

Just a quick question....... When looking at different circulation pumps what does the sizes mean regarding 4m, 6m & 8m head???

Thanks.
Click to expand...

It's relates to the total height you need to pump the fluid, taking in to account any friction.
 
redcuckoo said:
When looking at different circulation pumps what does the sizes mean regarding 4m, 6m & 8m head?.
Click to expand...
The head is the total pressure drop round the circuit, due to friction etc. It has no connection with how high the pump has to push the water.
 
My pump is situated in the airing cupboard upstairs next to the hot water tank at about waist height. Would this make any difference to what pump i need say in terms of the pump not being on ground level????
 
It does relate to the height it needs to go actually and it takes in to account frictio. The meters head is a calculation of psi which also determines how far it will push it
 
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doitmyself said:
The head is the total pressure drop round the circuit, due to friction etc. It has no connection with how high the pump has to push the water.
Click to expand...

Geodetic head is the difference between the switch off point of the pump and the outflow height where the Manometric head is the sum of the total friction loss and geodetic head.
(As taken from the Jung Pumpen catalogue)
 
Maybe Grundfos don't know what they are talking about too!

Head

Technically head means meters of water column. It indicated how high a given pressure can lift a column of liquid. Knowledge of the relationship between flow and head and about the conversion between head and pressure will enable you to perform basic sizing of a pump for a specific application.
 
kay-jay said:
In laymans terms head is a measurement of the oomph that a pump has.
Click to expand...

And it based on a new pipe which is smooth bore (different pipe materials have different friction loss calculations) and a set of standard parameters. Without looking it up I believe it is based on sweeped elbows being used and if sharp 90 degree elbows are in the pipe run then you lose 0.5m duty for every sharp elbow after the 3rd sharp elbow.
 
Thermological said:
It does relate to the height it needs to go
Click to expand...
Only in the fact that the higher the building, the longer the pipe runs, so the greater the friction.

Take a simple circuit: one rad and a circulator. Connect them together by 100 ft (each way) of pipe. It wouldn't matter if the rad was on the same level as the pump or 100 ft above the circulator. The head will be exactly the same.
 
rpm said:
Geodetic head is the difference between the switch off point of the pump and the outflow height where the Manometric head is the sum of the total friction loss and geodetic head.
(As taken from the Jung Pumpen catalogue)
Click to expand...
But that's talking about a pump to transfer a liquid from one level up to another, e.g from a well to a storage tank. The "pump" used in a heating system should be referred to as a " circulator". It just pushes the water round and round. How far up it has to push it is irrelevant.
 
lol..... I dont blame you!! I was lost to it all after the first few replies i had on this post!! Enjoy your sunday afternoon :)
 
Pump head is measured in ft or meters . The static head of a pump is the maximum height of which the pump can deliver. The max output of a pump at a certain output or rpm can be read in graphs by lookin at the curve in relation to the flow against the height so flow is where your friction comes in and head your height . So every pump comes with the pics of the curve graphs showing you the output
 
doitmyself said:
Only in the fact that the higher the building, the longer the pipe runs, so the greater the friction.

Take a simple circuit: one rad and a circulator. Connect them together by 100 ft (each way) of pipe. It wouldn't matter if the rad was on the same level as the pump or 100 ft above the circulator. The head will be exactly the same.
Click to expand...

The higher the building the greater the head and greater the friction but head is what we measure not friction.
 
I thought I would just chuck a quick explanation of what head was to the poster! lol
 
Thermological said:
Maybe Grundfos don't know what they are talking about too!

Head

Technically head means meters of water column. It indicated how high a given pressure can lift a column of liquid. Knowledge of the relationship between flow and head and about the conversion between head and pressure will enable you to perform basic sizing of a pump for a specific application.
Click to expand...
Of course they know what they are talking about. It's just that you think it's related to how far the highest radiator is above the pump; which it isn't.

"Metres of water" is just a rather antiquated method of measuring pressure. Nowadays it is measured in Pascals (Pa) or kilopascals (kPa).

Read Copper Tubes in Domestic Heating Systems, which explains how to size a pump. You won't find an reference to height in the document.
 
Yawn yawn yawn

I've been in this industry over 20 years and I know what it is and what I think it is.

The poster just wanted a simple explanation which I gave him and also mentioned friction which I am well aware plays a big part.
 
Thank you Thermological, i much appreciated both of your help. I didnt want or expect my post to turn into some kind of battle of minds though... I have no doubt what you are both saying is equally correct :)
 
doitmyself said:
Maybe you need to go back to school and get some retraining.


But he also wanted a correct explanation.
Click to expand...

I don't know about you but I didn't learn my trade in school.

But by the way your going on your still in the school playground.

I've finished on this topic and won't be posting again I've got better things to do.

Why don't you post the whole calculation so the original poster can get even more confused.

Enjoy the rest of your weekend, I know I will.
 
Doitmyself.

wind it in, you're starting to get noticed for all the wrong reasons.
 
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