central heating circuit diagrams

[Darth Ai]

I want to relocate my existing primary circuit heated hot water tank to another location in my house which will require me to install a 'Y'-type system with a motorised three way valve. I've searched the Internet, without much success so far, to find a clear circuit diagram which will help me complete the re-piping of the system.

Does anyone know of a good source of diagrams either on the internet or elsewhere which will help me design my pipe circuits? I think I understand what I need to do but seeing in a picture/diagram would be worth a thousand words. I am especially puzzled or concerned to know if I need to fit some kind of bypass system around the motorised valve for either maintenance or summer running.

TIA for any help than anyone can give me

Darth

[IMM]

Fill us in more and we will talk you though a system.

[mike ring]

"Darth Ai" wrote in news:BKQSc.133420$ [e-mail]:

diagrams on page 4

and

they are specific makers the parts are so interchangeable this should be all you need.

PS if you're changing things consider "S" plan - it's better.

You don't normally need a bypass, the pump and boiler are called by the valve opening, and can't start if there's no water path through rads and/or HW cylinder

HTH

mike

[Darth Ai]

The current system is a very simple vented system. The boiler is a Rayburn gas range cooker. The primary circuit heats the cylinder which is placed about 3 metres vertically above it by gravity alone. A 't' on the flow side of the primary circuit leads to a pump which circulates the central heating system and the return also 't's into the return side of the primary circuit. I should add this is all in a typical north london, georgean terrace house which is 3 storeys.

My plan is to raise the hot water cylinder from the room above the boiler on the 1st flow to a position directly above it on the 2nd floor. I'm fairly certain that the additional distance will mean that relying on natural circulation of the primary circuit alone will not heat the hot water tank sufficiently, therefore I'm assuming I will have to pump the primary and therefore install a 'Y' type circuit (which I am also assuming will be the easiest/simplest circuit for me to install as a DIYer).

The only diagram I've so far found to work from is this one:

I wanted to know if this is a simplified schematic or if I can actually rely on this diagram alone to design my system. I recall on one similar system I saw some kind of bypass (not too sure where) and some way to isolate the central heating circuit entirely by moving a lever on the valve so that in the summer the central heating circuit was entirely out of the loop. Also, are there any other "bleed" vallves I need to insert in the circuit other than at the top of the primary circuit?

Given the fact that I'm raising the tank I can actually take advantage of a lot of existing pipework which is why the 'Y' system appeals. I also do not need separate zones etc. Looking at the diagrams the 'Y' circuit seems to be the simplest scheme.

Does any of this make sense and can you make any further recommendations?????

TIA

Darth

[Ed Sirett]

The main FAQ for this group has a lot of diagrams for both the water and electrical aspects.

[John]

If its a standard big lump of iron Rayburn then he WILL need to make arrangements to dump heat from the unit when the heating is off and/or the hot water is satisfied. Best advice is to consult AgaRayburn

[John]

Your post did not make clear what type of Rayburn you have but if the "boiler" part is composed of a big solid lump of cast iron which is heated by the same burner as the rest of the cooker as the early ones were then it isn't possible to stop the water heating up when the cooker is in use so turning off the flow to rads or cylinder primary will lead to the water within the boiler actually boiling (ie rising to 100 deg C). A heat dump is a radiator fed by gravity which dissipates the boiler heat - wasteful but neccessary with this setup. You might have a more modern Rayburn such as the Royale which has two seperate burners one for the cooker and one for the boiler. In this case it is possible to control the units seperately. As I said it is best to ask Rayburn for a true assessment and correct answer!

[Darth Ai]

John, you're right about contacing Rayburn and I'm going to call them on Monday. But, as you point out, it is one of the more modern ones with a separate boiler unit which is independently thermostatically controlled.

Whilst at the Rayburn site I noted that this type of Rayburn will support a primary circuit working on pure convection up 20 metres in length. If this is the case all I'd need to do is extend my existing primary circuit and I don't have to bother with pumping it and all the attendant changes to pipework, valves etc etc. Seems hard to believe which is why I want to confirm with Rayburn directly.

Cheers

Darth

[mike ring]

"Darth Ai" wrote in news:ctaTc.125072$ [e-mail]:

That's 28mm pipes for you!

mike

[Darth Ai]

Not necessarily a problem as the rise is vertical straight to the cylinder. I'll have to step down to 22mm for the final turn and connections, though.

Darth

[mike ring]

"Darth Ai" wrote in news:T0mTc.128770$ [e-mail]:

I really meant that 28mm pipes are good for convection because the fatter the pipe, the better; if you're pumping you don't need such thick pipes.

And do you have to step down? surely the necessary fittings are available, and after the awful things I've just ripped out I'm getting obsessive about not introducing any unnecessary constrictions!

mike

[Darth Ai]

Again, Mike, you are probably right. I'm just not as familiar as I used to be with the conversion between the tap fittings on the cylinder and the pipe fittings. I'll have to ask my friendly plumbers merchants what they can supply! If you are right, hopefully I can just connect 28mm pipe directly to the fittings on the cylinder, if not I'll have to step down to 22mm.

I don't know if I should confess this here but I am looking to try and do this entire job using speedfit connectors. I'm only a DIY-er and I'm looking for the most painless path to completing the job. I don't care how pretty it looks because it is all in cupboard and the pipes themselves are routed straight up through existing cupboards on all floors. In fact, given some of the spaces I have to work in I doubt I could safely get a blow torch in to make straight connects.

I need to try and do this entire job in about 2-3 days.

Cheers

Darth

[mike ring]

"Darth Ai" wrote in news:NMtTc.132452$ [e-mail]:

If you are right, hopefully I can just

If you're having your cylinder built to order perhaps you could specify

28mm fittings - I just bought a quick recovery that has 22mm compression fittings as standard and it's a lot easier than fooling around with BSP.

I don't see anything wrong with that, but there are various types and qualities of plastic fittings that you may get advice on from folks who've used it - I stick with copper for cheapness (and elegance) of end feed fittings, but mainly because I don't want to have to learn about plastic assembly and demounting.

Good luck - mine's taking more like 2-3 months, but there's just me and I've got mains water and an electric shower and it's summertime...

I guess I'd better sweat up another joint or two tomorrow, me zone valves (Myson, with the pretty blinkenlights) and the full bore 22mm circulating pump ball valves, are coming Monday

mike

[IMM]

Speedfit are about the worse plastic fittings.

Two or three days? Get a combi and connecting is them simple.

[Lurch]

On Sun, 15 Aug 2004 00:03:44 +0100, "IMM" strung together this:

To be fair, if you cut the pipe properly then all is well. Thickos who can't use tools and\or pipe properly would find anything useless.

Only one?

[IMM]

Mr, Pole, I would go along with that.

You are right two would be better. My God Bean, you have 2/2 right.

[Darth Ai]

To be fair, I don't think I would even contemplate returning to DIY plumbing if speedfit had not come along. I've been very careful when using speedfit to cut pipe squarely and I always clean pipe ends as though I am going to sweat them which may seem extreme and obsessive. My father was a complete nut about cleaning things up before assembling them and somewhat drilled the practise into me, be it car mechanics, electrics or plumbing. I suspect it was a carry over from his days in the services.

So far I have never had a problem with 15mm or 22mm fittings for both mains and tank/cylider feeds. Haven't tried them on c/h which is why I'm a little anxious about using them for the straight connections and elbows in my 28mm piping. However, they are reputedly suitable for all c/h use so I'll press ahead with speedfit and see what happens!

I still don't know what a "combi" is unless this is referring to a combi boiler in which case I don't understand the relevance to this thread.

Darth

[IMM]

I strongly advise you not to use Speedfit. Marley Equator and Osma Gold are far superior. You may regret it.

He does mean a combi boiler and there is not relevance to this thread. I think Mr Pole is confused.

[Lurch]

On Sun, 15 Aug 2004 15:19:38 +0100, "IMM" strung together this:

Er, you started with all the talk about combi boilers.

[IMM]

He is a DIYers, so requires simple appliances to fit. A combi is simple for him to fit. he should reassess his requirements.