Replacing Hot water/CH system in Townhouse

htgeng said:
ollski said:
From the bs:

The expansion relief valve shall be fitted on the supply pipe close to its connection to the heater without any intervening valves.

Normally goes stop cock, strainer, pressure reducing valve, check valve, expansion relief

wow thanks for all the kind words - ivory towers and all that. All points made were considered during installation. I'd love to see pictures of some of your work lads!

do you own a drill ?
yes, several
do you own benders?
how about lagging?
picture was taken before lagging
no secondary ret?
was not required by customer.

No, no mate not knocking anything, just trying to clarify the point chris was making, you know with the definitive word...its a nice job, but nobody is ever looking for the good bits when we get a tasty photo to pore over ;)
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I am assuming you've done the unvented assessment at some point, but you don't seem to have understood the importance of getting all the controls and safety devices installed strictly in accordance with regulations and manufacturers instructions.

Otherwise you would appreciate that placing an isolating valve (not to mention a check valve) between cylinder and expansion valve is potentially dangerous. Every unvented cylinder is a potential bomb. We have a duty to ensure that every installation is technically flawless.
htgeng i think if you look up the byelaws i think you will find a sec ret is required over a certain distance to conserve water,also pipes should be adequately supported and pulled bends aid circulation and noise suppression[velocity of water],i was not critising your work just pointing out some valid points[ithought they were valid]sorry if i offended :) :)
We are located in SW1, and would probably need something similar to the property in WC2(A). How do I email you on here for more details? my email is [email protected] - could you send me details of this system?

- Which boilers can have an extended flue? i.e. from basement, up 4 storeys? (B)
- Are there any diagrams for a system like this (including CH), with recommended pipe sizes etc? (C)

(A) WHat you're looking at there is "just" an unvented cylinder. OK if your mains is good to Very good. You can get away with poor mains pressure as long as the pipes are big so the flow can be high. 1bar through 35mm copper is a heck of a lot of water.

(B) Well you could look at Kestons, though it's fairly unlikely you'd need it to go up 4 floors. Internal or external? There are others.

(C) What you need is an engineer to take all the parameters into account then come up with a design, it isn't a Wickes leaflet job. A lot of plumbers couldn't do it, unfortunately.

There would be a problem putting an unvented cylinder in a coal hole, because the discharge pipe has to fall. It can go into a main drainpipe under certain conditions. Not something found in a typical place like that.

You could put your water storage cistern(s) down there, and pump(s), with the HW cylinder higher.

You'd then want 2 pumps, because you'd have nothing by gravity if a single pump failed.
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You could also boost a restricted mains water flow by using an "accumulator", a large pressure vessel that fills with mains water when there is no demand on water supply, and then empties to boost flow when taps are opened. Bulky to accommodate and not widely known about, even amongst heating engineers.

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