Central Heating Zones - New & Replacement Systems

[rodders]

According to the Domestic Building Compliance Guide (2010 with 2011 amendments) page 22 it states:

"Dwellings with a total usable floor area up to 150m2 should be divided into at least two space heating zones with independant temperture control, one of which is assigned to the living area."

How are you guys installing these systems? For a combi do you need a one or two channel programmer (it says temp control not time control?). I take it you need two flows from the boiler (will a three port valve do or do you need 2 x 2 port vavles?) and do you need 2 returns (to stop reverse cirulation?) Do you fit check valves to stop reverse cirulation too? Does this cause problems draining down? What about the extra cost to the customer?

As an apprentice, I worked for a big company and we never fitted systems like this but now I'm working for myself I want to make sure I'm doing everything correctly.

Cheers

[diamondgas]

Hi rodders 2 zones on and 's'plan 3+ on an 's'plan+ i think you call it Individual temp control can be room stats although the whole of the heating still needs to be timed! Regards the return it's best to common the circuits before joining together I'd say

That's my opinion though and there are plenty more avid installers with more experience who could better advise from experience

[rodders]

Cheers for the reply, lets say its a combi system, how do you split the 2 zones for the heating (upstairs and downstairs obviously) but how do you do it? 2 port valves? One on the upstairs flow and one on the downstairs? Where would you site these valves? Under the boiler? I've never seen this out on site and as an apprentice I never fitted combi heating systems this way.

Lets say you got a combi, do you need 2 room stats (one upstairs and one downstairs if so where upstairs would you situate the room stat?) and a 1 channel programmer? Get sparky to wire it in?

Sorry for all the questions but I am struggling to visualise this system any one got some photos they dont mind sharing?

Thank you.

[diamondgas]

Turn it on it's head rodders, how would you pipe it and design it! I use to get out a pen and paper, in fact have done for my own home that's currently under refirb. Got 3 zones and hot water (4)!

[rodders]

Cheers did you use 2 port valves for the different flows? If so, were they postioned under the boiler ?

[croppie]

Think simply Rodders. Where is the logical place to split the flows, an airing cupboard? Under the stairs? Possibly at the boiler? Where you split them is where you'd put your zone valves.

[diamondgas]

Cheers did you use 2 port valves for the different flows? If so, were they postioned under the boiler ?

Actually putting 28mm 2 port on 22 pipe Just to guarantee enough flow through For my own they're going in the garage, along with the boiler and UV cylinder . Ease of access when they need repaired/replaced. Note I said when because they will as some time in the future! Place your valves wherever is the best place just make sure they're serviceable! Regards your returns the circuits do need to be commoned before branching back in! You can't just run one return willy nilly

[rodders]

Cheers for this,

for a combi just need a one channel programmer then?

(sorry for all questions lol)

[croppie]

A channel per zone Dave.

[rodders]

I ask because it says

"into at least two space heating zones with independant temperture control"

and more than 150m2 it says time and temp control. So one channel?

[chris watkins]

Lets say you got a combi, do you need 2 room stats (one upstairs and one downstairs if so where upstairs would you situate the room stat?) and a 1 channel programmer?

rodders the reason they want to have the heating spilt up into the two zone it that there is some energy savings to be gained if the heating in the sleeping areas (bedrooms) of the house can be turned off when no body in these areas, which makes sense if you think about how most people use there houses (bedrooms only need heating when we get up & then again when we go to bed) (unless you want a quickly in the afternoon, ar' they were the days !) sorry, day dreaming again !! anyway this means that you do need time control as well as temp (part L does state this) the easy way to achieve this is to use a programmable room thermostat upstairs controlling a zone valve. You can do the same downstairs as well, easer to link these to 2 ports rather than a 3 port.
Do you know how a 2 port valve works with the micro switch ???

[AWheating]

if the property only has an upstairs bog them i would put the bathroom off the living zone.

[rodders]

I get the reason they require this to be done. I know how a 2 port zone valve works, but I wonder who actually does this? I been in hundreds of houses fitted loads of new and replacement systems and never seen it done.

What happens if someone wants a boiler replacement but just had new carpet and decorating and dont want all the boards up to fit an extra flow and return?

[rodders]

I get the reason they require this to be done. I know how a 2 port zone valve works, but I wonder who actually does this? I been in hundreds of houses fitted loads of new and replacement systems and never seen it done.

What happens if someone wants a boiler replacement but just had new carpet and decorating and dont want all the boards up to fit an extra flow and return?

Not to mention the extra cost of copper and fittings, labour and room stat etc.

I'm finding it hard to believe this is done but I don't know?!

[chris watkins]

What should be done (by law) & what is actually done are not necessarily the same thing (like driving a 70 on the motorways) but it does save a bit & if you register your installations under part L you are certifying that it is compliant ! As usual it boils down to wether you do it by the book or not, if only the law was enforced we would all be playing on a level field !!! Fat chance but we should be pushing for it. (plumbing registration by the back door)