FAO ecowarrior etc. How did I do?

[gaswizzard]

No plate to plate , the water in the boiler goes through the low loss header and circulates through the radiators/UFH/cylinder coil and back to boiler.

isn't this a sparky forum?

 

[kevindgas]

No plate to plate , the water in the boiler goes through the low loss header and circulates through the radiators/UFH/cylinder coil and back to boiler.

thanks!!

isn't this a sparky forum?

it was but its been hijacked

 

[gaswizzard]

 

[ebee]

I won my argument with the heating engineer that surely the loop would require a pump far bigger then the individual zone and boiler pumps.

You say you won this argument?

and what did the system designer have to say about you re-specifying the shunt pump?

Sorry, I`ve been away a few days.

When I say I won the argument, to be truthful I made a comment and asked a question , initially I was poo pooed then after a few weeks the pump was changed and the heating engineer told me I was correct.

My comment/question was seeing each of the three boilers has a pump of a certain capacity pumping hot water into the large bore header loop thingy and each zone then has the same capacity pump taking hot water from the header loop thingy then it seems to me that the pump circulating the header loop thingy itself needs a pump not of an again equal capacity to all the others but quite a bit more say perhaps 3 or 4 times more or at least twice perhaps. They did end up changing to a pump of such a larger and when I noticed it the heating engineer told me I was correct.

As I said before I was trying to get my head around the temp sensors on zone returns rather than flowpipes to monitor them. Fascinating for a humble spark to grasp.

 

[gaswizzard]

Sorry, I`ve been away a few days.

When I say I won the argument, to be truthful I made a comment and asked a question , initially I was poo pooed then after a few weeks the pump was changed and the heating engineer told me I was correct.

My comment/question was seeing each of the three boilers has a pump of a certain capacity pumping hot water into the large bore header loop thingy and each zone then has the same capacity pump taking hot water from the header loop thingy then it seems to me that the pump circulating the header loop thingy itself needs a pump not of an again equal capacity to all the others but quite a bit more say perhaps 3 or 4 times more or at least twice perhaps. They did end up changing to a pump of such a larger and when I noticed it the heating engineer told me I was correct.

.

Lets put this thingy in a nutshell

If total boiler power = 100kw then.....

20c delta t = 100kw/84 = 1.19 litres per second flow rate through header/loop
10c delta t = 100kw/42 = 2.38 litres per second flow rate through header/loop

Total flow rate for zone circuits (100kw) would be equal to boiler/ring circuit , unless of course zone circuit circulators (distribution) were sized for a 10c dt with ring/header (load) sized for a 20c dt. if this were the case then a quick calculation based on 'mixing temps' through header would reveal whether the installer/designer is in deep poop or not.

Circulator head is a different thingy altogether , head/friction loss through boiler/ring circuit would be considerably less than zone circuit/s loss.

 

[ebee]

Wow that is certainly impressive and way above my head.
I`m not sure whether you are saying that my gut feeling was right or wrong.

My feeling was, that a header loop although of a relatively short loop distance but a large internal diameter would need a relatively large pump in order to circulate water as fast or indeed faster than the combined flows into it from the boilers and also as fast or faster than the combined flows out of it to the zones for heating. Therefore if the 3 boiler pumps and the 4 zone pumps have X capacity then the header pump might need 4 X or 3 X capacity and not simply X capacity as er the original pump .

It was a rule of thumb guess just by looking at it and having the heating engineer explain what it did. I expressed surprise that that it was not of larger capacity and he dismissed it as not required to be.
A few weeks later I noticed it had in fact been changed for a larger one and he said that my feeling was indeed correct for the system to work as it should.