static pressure

[dotto]

Hi all. I am a bit confused about the definition of this word in C.H. system.
1) Is the static pressure of an open vented C.H. system given by the length of cold feed pipe from F&E tank till the point it joins the primary flow?
2)If an open vented C.H. system works at its best when under positive pressure ( above athmospheric pressure- so above 1 bar) does it mean that the pump must be set at above 1 bar? Thank u very much 4 clarifying these points.

 

[Softus]

What are the symptoms of the problem with your plumbing and/or heating system?

 

[dotto]

What are the symptoms of the problem with your plumbing and/or heating system?

Just a clarification on a book i am reading.

 

[Softus]

1) Is the static pressure of an open vented C.H. system given by the length of cold feed pipe from F&E tank till the point it joins the primary flow?

No. That is commonly termed the "head", although it's determined by height, not length.

2)If an open vented C.H. system works at its best when under positive pressure ( above athmospheric pressure- so above 1 bar) does it mean that the pump must be set at above 1 bar?

No. The pump pressure is not adjustable.

Static pressure usually, although not exclusively, means the pressure in a system when no fluid is flowing.

 

[oilman]

Static pressure usually, although not exclusively, means the pressure in a system when no fluid is flowing.

True. It is also a variable constant since it varies with the height in the system at which you measure it if it is open vented.

If the tank is in the loft, (20 feet above ground) static pressure is about 1/2 bar plus a bit. Circulating pumps don't like low pressure as it probably means they are near the top of the system and can suck air in. If they are near the ground they tend to work better.

 

[dotto]

Static pressure usually, although not exclusively, means the pressure in a system when no fluid is flowing.

True. It is also a variable constant since it varies with the height in the system at which you measure it if it is open vented.

If the tank is in the loft, (20 feet above ground) static pressure is about 1/2 bar plus a bit. Circulating pumps don't like low pressure as it probably means they are near the top of the system and can suck air in. If they are near the ground they tend to work better.

Thank u very much 4 answering guys.

 

[Spark123]

I take it the static pressure is measured as gauge pressure, i.e. as the differential pressure in the pipework against atmospheric pressure?
The measurement of a pressure against zero atmospheric pressure is called the absolute pressure iirc.

 

[Softus]

I take it the static pressure is measured as gauge pressure, i.e. as the differential pressure in the pipework against atmospheric pressure?

Why do you assume that?

The measurement of a pressure against zero atmospheric pressure is called the absolute pressure iirc.

You can call it what you like.

 

[Spark123]

I assumed (bad idea to assume I know) that as atmospheric pressure will be acting on the system the same way throughout then it will no effect the head pressure. Maybe a bad assumption, please correct me if I'm wrong.
Do you guys use absolute or gauge pressure? I was just trying to understand the original post where the OP refers to absolute btw. Why use absolute?
Terminology can be important when buying expensive test equipment

 

[oilman]

Gauge pressure

 

[Spark123]

Thanks, so is the OP referring to 1bar above atmospheric is a red herring? iirc to get a head pressure of 1bar you need to have a header tank 10m above the point you are measuring, but it's been a while now

 

[Softus]

I assumed (bad idea to assume I know) that as atmospheric pressure will be acting on the system the same way throughout then it will no effect the head pressure. Maybe a bad assumption, please correct me if I'm wrong.

You're wrong, but it's not really important I think.

I was just trying to understand the original post where the OP refers to absolute btw.

He was talking gibberish.

Thanks, so is the OP referring to 1bar above atmospheric is a red herring?

Yes.

iirc to get a head pressure of 1bar you need to have a header tank 10m above the point you are measuring

I believe that you're exactly right (for pure/distilled water).

 

[doitall]

The static pressure is the height between the header tank and the highest part of the system.

That should get the cowboys going

 

[Spark123]

Cheers lads, I sort of understand now. Isn't the header tank the highest part of the system though????

 

[oilman]

The static pressure is the height between the header tank and the highest part of the system.

That's zero then, since the highest part of the system is the header tank