bypass valve to swich off boiler?

[IMM]

So you have been on meths.

You haven't a clue what you are on about.

[IMM]

I don't actually.

[IMM]

Directing people to info for understanding purposes is different to saying "buy Polyplumb". I direct people to DPS for an understanding of heat banks, but I don't say buy DPS.

[Ed Sirett]

ROFL. I suppose he means that the pressure differential available at the manifold is nearly constant because the flow losses in the microboore pipes are perhaps a magnitude greater than the losses in the manifold-boiler-pump-manifold part of the circuit. Well that's a part of it. The bigger part is getting the balance right between what is needed to each radiator - which even in the "Play School" house will vary due to a) Different solar gains in the rooms. b) Differing windows in the rooms c) Differeing temperature requirements in the rooms.

[IMM]

You are getting there. Also no other radiator leg can influence another, as they are not connected, being connected to neutral points, the manifolds. Do some more looking up.

The rad size calculation tales care of this.

This is set out in the design, which caters for the worse case senario of no solar gain and -1 or -3 outside. The rads will be pretty much self balnacing, once the pipes from the manifolds are sized correctly.

[Andy Wade]

This is codswallop - and to think you call yourself a professional! The pump is not a constant pressure source, the boiler and the pipework linking boiler, pump and zone valves (if any) to the manifolds all have finite flow resistance, not necessarily negligible. And you're misusing the term 'neutral point' which in my book is a point in the circulating loop at which the absolute pressure does not change when the pump is turned on or off.

All you can say is that the interactions will tend to be much less than in a typical minibore system, that there is much less chance of a 'short-circuit' condition arising, and that the performance of a manifold-fed microbore system will tend to be more tolerant of balancing errors. All of which has been said before, many times.

[The Natural Philosopher]

Ah. Plumbing for morons. NOW I understand.

[The Natural Philosopher]

Professsional moron. Like the government in power.

[IMM]

No it isn't.

'short-circuit'

You are getting there. You could go commercial and have a pressure sensor on the manifold and vary the pump speed to maintain a constant pressure. That is getting too complicated for domestic though.

[IMM]

It is clear you don't understand.

[Andy Hall]

Moving the goalposts again?

When you are in a hole, it is usually better to stop digging :-)

.andy

To email, substitute .nospam with .gl

[IMM]

Nope. In fact was considering doing this in a previous house I had. I had a the controller and and all the gear.

What hole do you refer?

[The Natural Philosopher]

The one you never see, where the sun doesn't shine..

[IMM]

You have been at the meths again!

[Andy Wade]

The hole /to which/ Andy referred is the one you started digging on the 12th of January 2000 when, in this newsgroup, you posed the unforgettable question

"Is this linear speed in cubic metres per second?"

and which can be seen here .

Then on the following day, in this post,

you revealed your source of information on heating system design to be not the respected CIBSE Guide (which one would expect of an HVAC professional) but rather "Haynes Plumbing books". Confusion about the difference between linear velocity and volumetric flow rate continued. Ho hum... (I read that whole 38 article thread, again this afternoon - most entertaining.)

The hole must be very deep by now. I keep looking to see whether you've started posting from an Antipodean domain.

[IMM]

Which it isn't. The CIBSE is a poor book, very expensive for what it is has very thin content, poorly formatted and looks very amateurish, obviously written in Word 100%, even the tables. It even has mistakes. It is fine as a reference for those in the business, not a DIYer, with too much assumption of knowledge.

Not on my part. I may have been taking the mick with some know-it-all though.

You read 38 old posts? How sad.

No hole at all. Go and understand what a manifold can do you you.

[Andrew Gabriel]

Was that the book with the bullshit about not having to balance microbore systems, presumably because it thought the physics of balancing a system was beyond the comprehension of most in the business (or maybe just beyond that of the author)?

[IMM]

I advise you to go and read some of these books and learn something about heating, as your knowledge is sadly lacking.

[The Natural Philosopher]

Whereas in your case, irrespective of how much you read, your understanding stays the same small quantity.

[IMM]

You are scrapping the barrel in a poor attempt to be witty. Now stay off the meths.