Extension central heating design & pipe/pump sizing

[craigskelly]

I hadn't thought about using a manifold/activators but I like the idea in theory at least. The only thing is that the pump and new radiators are at other ends of the house so unless I run separate runs to the new upstairs and downstairs sections (which I could do I guess) then I wouldn't be able to separate the flows properly unless I guess the activator went somewhere at the beginning of the new extension i.e. single new pipe run part of the way which then split between upstairs and downstairs sections. I assume flow can be better controlled/balanced using a manifold rather than trying to T off of an existing run. Time to re-visit my calculation sheet again I think.

 

[Ermintrude]

Check part l. As if your over allowance 70m2 it's got to be zoned in any case!!

 

[happyflyer]

Check part l. As if your over allowance 70m2 it's got to be zoned in any case!!

Ermi,

He needs to get the right amount of water into each radiator at the right temperature before he starts to control radiators and circuits, he thinks he
needs a pump 0.7kg/s @ 6.3m head, will this do for him, he's done the calcs, is he right with that pump, at the moment I think that's all that he's worried about.

Tony

 

[Howsie]

If that's all he's worried about then he's missing something...

 

[SimonG]

woods and trees ?

 

[happyflyer]

The current energy conservation level for domestic dwellings like all government intervention are feeble and entry level (zone valves). With a system this big you need to go much further or you will need deep
pockets to run a system like this, if this chap can work out the index circuit on this system, he will know how to control it when he's ready too.


This Government and previous ones have never had a proper energy policy, that's why they are talking about the lights going out this winter, lets just wait and see.

Please don't talk about Part L and making dwelling more efficient, when we still have a host of coal fired power stations running at 30% efficiency, its a joke, what you all do to keep Part L happy is a joke too and then there is the cost, tell the custard that it will cost an extra £250 for a proper control system room by room (not TRV please) and they go all cold on you, no just fit the standard two zone valves, Europe do much better. We are pretty far behind guys, never mind there is still shale gas, its the FUTURE!!!

 

[happyflyer]

Perhaps read this, its interesting:


https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/8390/2076716.pdf

 

[tamz]

Ermi,

He needs to get the right amount of water into each radiator at the right temperature before he starts to control radiators and circuits, he thinks he
needs a pump 0.7kg/s @ 6.3m head, will this do for him, he's done the calcs, is he right with that pump, at the moment I think that's all that he's worried about.

Tony

Too late to be bothered with the sums but a quick look tells me a bundle of 3/4 would solve a lot of problems.
There is always a way.

 

[tamz]

Btw Tony, are you Tony?

If you are you will know what i mean.

 

[happyflyer]

Btw Tony, are you Tony?

If you are you will know what i mean.

Tamz ???? LIke the bit about 3/4" tube BTW Tamz its 22mm now or is it still 3/4" in Scotland

 

[Gray0689]

Tamz ???? LIke the bit about 3/4" tube BTW Tamz its 22mm now or is it still 3/4" in Scotland

Why where are you from tony

 

[tamz]

3m 2 and an 1/8th :wink:

 

[happyflyer]

For people who are pipe sizing this is how I would approach it:

15mm will carry 0.141kgs this will feed a rad or a number of rads with a maxium output of 6kws
22mm will carry 0.311kgs this will feed a rad or a number of rads with a maxium output of 13kws
28mm will carry 0.519kgs this will feed a rad or a number of rads with a maxium output of 21kws
35mm will carry 1.190kgs this will feed a rad or a number of rads with a maxium output of 49kws

These figures are based on water flow in all pipe sizes of 1 m/s, if people attempting to design
stick to these figures they will not go far wrong.

Extending an existing system brings its problems, you are not certain the first person got it right
and you should lift some FB if you can and do some investigating, if you an expert plumber you should be
able to sniff it out without lifting the board, if you see some 15mm and 10mm mixed to radiators lift the boards

A simple way to pipe size would be standard pressure drop, that way you only need to measure the full lenght of the
index run and x by the pressure drop per mtre plus the boiler drop etc.