Gravity hot water to fully pumped / sealed

[SJB060685]

How do I change the numbers John to calculate?

 

[ShaunCorbs]

How do I change the numbers John to calculate?

in excel I’m guessing well that’s where I would think it’s made

 

[SJB060685]

Yes I've worked it out thanks Shaun. Still getting used to my new phone

 

[ShaunCorbs]

Yes I've worked it out thanks Shaun. Still getting used to my new phone

same got no home button now

 

[John.g]

That's it, it was in lotus 123 originally before excel was even heard of!!
I have just added another "box" to give a taste of a fairly typical (fully sealed) installation, its quite handy.

 

[SJB060685]

Thanks John mate. Question. Theres no mention of static head or system volume in these boxes. Why is that?

 

[John.g]

Re Static Head, I didn't include this is because I don't know where the EV will be located, if its located just above the boiler on the ground floor then you would add ~ 0.1 bar to the final pressure to get the maximum (and ) boiler system pressure, more significantly, but a bit unusual, if the EV was located in the attic then you would add ~ 0.4/0.5 bar to the final (EV) pressure to arrive at the maximum (and ) boiler system pressure, if in the hot press then add - 0.25 bar, and so on, with EV mounted above boiler (ground floor) then the pre pressure should not be less than 0.4/0.5 bar to ensure that you will get circulation through the upstairs rads on boiler start up.

Re System Volume, again I didn't include it directly in the calcs BUT I give a table with the % expansion for water temps from 50C to 110C, so for example if you estimate that your system contents are 100 litres and that the flow/return temps are say 75C/60C, mean of 67.5C...from the table this equals ~ 2% expansion so total expansion is 100*2% or 2 litres which you insert in the yellow box adjacent to "expansion"
You can see the calculations in the excel S.Sheet if you highlight each cell.

 

[SJB060685]

Thanks John. I was overlooking thermal expansion coefficient on the left of boxes
[automerge]1578166817[/automerge]
How would an expansion vessel under charged at ground floor level affect circulation in upstairs rads on start up @John.g?

 

[ShaunCorbs]

Re Static Head, I didn't include this is because I don't know where the EV will be located, if its located just above the boiler on the ground floor then you would add ~ 0.1 bar to the final pressure to get the maximum (and ) boiler system pressure, more significantly, but a bit unusual, if the EV was located in the attic then you would add ~ 0.4/0.5 bar to the final (EV) pressure to arrive at the maximum (and ) boiler system pressure, if in the hot press then add - 0.25 bar, and so on, with EV mounted above boiler (ground floor) then the pre pressure should not be less than 0.4/0.5 bar to ensure that you will get circulation through the upstairs rads on boiler start up.

Re System Volume, again I didn't include it directly in the calcs BUT I give a table with the % expansion for water temps from 50C to 110C, so for example if you estimate that your system contents are 100 litres and that the flow/return temps are say 75C/60C, mean of 67.5C...from the table this equals ~ 2% expansion so total expansion is 100*2% or 2 litres which you insert in the yellow box adjacent to "expansion"
You can see the calculations in the excel S.Sheet if you highlight each cell.

Thanks John. I was overlooking thermal expansion coefficient on the left of boxes
[automerge]1578166817[/automerge]
How would an expansion vessel under charged at ground floor level affect circulation in upstairs rads on start up @John.g?

might be best to start a new thread as im sure theres more people who would like to learn this information

 

[SJB060685]

Would you mind starting it mate? I wouldn't know how to word it lol