Custom made Low Loss Header advice

[Pipedreamer]

Hi Gents.

Looking for a bit if advice regarding low loss headers.
I have fitted a few with my old employer where he would get them made up custom.

However im now out on my iwn and want one made up however im unsure of whats best practice for the primary circuit connectioms on the header itself.

He used to have the flow at the top and the return at the bottom on one side of the header with all the secondary flows and returns on the other side

Os it better to have the primaries like that or have them centred between the secondsry flow and secondary returns?

Ibe added a god awful drawing for a example. One example is in blue the ither in red.

Also an e gineer has recently told me that hes heard multiple outlet headers have problems but cant rwmember what and i cant remember any issues. Anyone shed any light on this?

 

[ShaunCorbs]

Ahh that seems extremely obvious now you ve pointed it out.

So if my circuits are 28mm would o substitute 28mm figures in tjat calculation for x 3 zones

Then the same for 22mm x 1 zone and then add them together for the figure of the kw of the load?

Yes so

Work the flow rates for the single 28mm zone then times by 3 if the same loading or work out the other two if different (flow rate)

Then work out the 22mm zone (flow rate)

Then add all 4 loadings (kw ratings)

That will give you the pump flow rate and header size
[automerge]1574804154[/automerge]

Ahh that seems extremely obvious now you ve pointed it out.

So if my circuits are 28mm would o substitute 28mm figures in tjat calculation for x 3 zones

Then the same for 22mm x 1 zone and then add them together for the figure of the kw of the load?
[automerge]1574803770[/automerge]

Well ive sort of done that ive done 50 ltr vessel for the 50 kw boiler. However they are adding a couple of rads so you reckon upsizing it is wise or overkill?

wise always oversize withing reason no harm in haveing too much expansion other than servicing it 😀

 

[Pipedreamer]

Yes so

Work the flow rates for the single 28mm zone then times by 3 if the same loading or work out the other two if different (flow rate)

Then work out the 22mm zone (flow rate)

Then add all 4 loadings (kw ratings)

That will give you the pump flow rate and header size

How would the 28mm zones be different load?
Would it not be the set amount of figures for each size pipe?

So you said 15mm is 0.14 litres so im assuming its always that figure and likewise the figure for 22mm 28mm and so on ?

Or have i got that wrong?

Yes so

Work the flow rates for the single 28mm zone then times by 3 if the same loading or work out the other two if different (flow rate)

Then work out the 22mm zone (flow rate)

Then add all 4 loadings (kw ratings)

That will give you the pump flow rate and header size
[automerge]1574804154[/automerge]


wise always oversize withing reason no harm in haveing too much expansion other than servicing it 😀

Haha very true
[automerge]1574804597[/automerge]
Also in your original equation whete does the 4.2 come from?

 

[ShaunCorbs]

Header size (diameter) in mm

you first need flow rate l/s

(the flow rate of 60kw Heating system with a delta t of 20degress is
60 / (4.2 * 20) = 0.71 l/s)

From the 60kw above 0.71 l/s

Convert to m3/s so divide by 1000= 0.00071m3/s

Stick in to the following

(0.00071 * 1.28)/0.3, Square root of that = 0.055meters

The 1.28 is constant, the 0.3 is velocity in m/s through the header

0.055 * 1000 = 55mm eg 54mm copper etc
[automerge]1574805004[/automerge]

How would the 28mm zones be different load?
Would it not be the set amount of figures for each size pipe?

So you said 15mm is 0.14 litres so im assuming its always that figure and likewise the figure for 22mm 28mm and so on ?

Or have i got that wrong?

Haha very true
[automerge]1574804597[/automerge]
Also in your original equation whete does the 4.2 come from?

depends if its sized correctly it might be under loaded eg not running at its max always best to size off the load
[automerge]1574805171[/automerge]
4.2 is your SHC (specific heat capacity of the fluid in the pipe) eg specific heat capacity of water and how much to raise it 1dc

 

[Pipedreamer]

Header size (diameter) in mm

you first need flow rate l/s

(the flow rate of 60kw Heating system with a delta t of 20degress is
60 / (4.2 * 20) = 0.71 l/s)

From the 60kw above 0.71 l/s

Convert to m3/s so divide by 1000= 0.00071m3/s

Stick in to the following

(0.00071 * 1.28)/0.3, Square root of that = 0.055meters

The 1.28 is constant, the 0.3 is velocity in m/s through the header

0.055 * 1000 = 55mm eg 54mm copper etc
[automerge]1574805004[/automerge]


depends if its sized correctly it might be under loaded eg not running at its max always best to size off the load

Oh Damn me everytime i think i understand i get confused again. Lol.

So how do you calculate load then?

Im gonba have to sit down and practice these rquations you ve given i think.
For ecample the one you ve given working it out at 55cm is making my head hurt haha

 

[ShaunCorbs]

Oh Damn me everytime i think i understand i get confused again. Lol.

So how do you calculate load then?

Im gonba have to sit down and practice these rquations you ve given i think.
For ecample the one you ve given working it out at 55cm is making my head hurt haha

write it out on a piece of paper and practice its not easy when you look at it but when you break it down its not bad just need a decent calculator just take it step by step

if you just want to size a llh post 23

pump sizing eg each zone / multi zone (flow rates) post 10

 

[Pipedreamer]

When i get time to sit down and practice these and try and work mine put can i pm you my workings see if im Damning it up or not?.

Now confused if im working out the 28mm flow rate or load and how.

Also where did you find the figure for 15mm pipe so i can source figures for 22 and 28mm?

 

[ShaunCorbs]

When i get time to sit down and practice these and try and work mine put can i pm you my workings see if im Damning it up or not?.

Now confused if im working out the 28mm flow rate or load and how.

Also where did you find the figure for 15mm pipe so i can source figures for 22 and 28mm?

its in the gas igem up 1

should be listed below if it works

header size use total kw eg calc in post 23

pipe sizing use post 10

 

[Pipedreamer]

its in the gas igem up 1

should be listed below if it works

Thank you.

Before i try and work this out. Im still unsure of the diffetence between working out the flow rate of the 28mm and working out the load of the 28mm.

What factors mean there is more load? Or is it literally how many rads are off each zone?

 

[ShaunCorbs]

Thank you.

Before i try and work this out. Im still unsure of the diffetence between working out the flow rate of the 28mm and working out the load of the 28mm.

What factors mean there is more load? Or is it literally how many rads are off each zone?

sorry prob confused you a bit with estimated load vs actual load

(forward thinking if you slightly oversize you always have some spare capacity if the customer wants to add some more rads later on off a branch / zone)

for header size you want need to size each zone just the total heat load on the header

 

[Pipedreamer]

sorry prob confused you a bit with estimated load vs actual load

(forward thinking if you slightly oversize you always have some spare capicty if the customer wants to add some more rads later on off a branch / zone)

Haha im definitelt confused but its me not you lol.

If i try and work this oit can i send you a photo and you tell me if im barking up wrong tree or getting it in ball park?

 

[ShaunCorbs]

Haha im definitelt confused but its me not you lol.

If i try and work this oit can i send you a photo and you tell me if im barking up wrong tree or getting it in ball park?

yep im busy atm so allow a couple of days if i dont respond just give me another pm 😀

 

[Pipedreamer]

yep im busy atm so allow a couple of days if i dont respond just give me another pm 😀

Bust? Whats that when its at home?
[automerge]1574806816[/automerge]
Ahh ypu mean busy. Ive got a cheek not realoaing that when im the king of typos

Thanks for your help

 

[king of pipes]

Heres one I did 8 years ago now just serviced it recently header is 65mm x 1500 long with 3 22mm circuits has performed well . Kop