Help with a Central Heating Design Please.

Hello all, sorry to post this again but the last thread got hi-jacked.

First of all I would just like to comment on a wonderfully stocked website with a miriad of helpful hints and tips. I think you all must just love a really juicy problem!!?

I'm not sure if this is one of those, but here goes:

I'm currently about to start the install of a completely new system. New boiler, tank, rads on the upstairs floor and living room, the rest of the downstairs is good and will be fed by it's own feed and return.

I'm zoning 4 areas.

Living room, main bedroom, guest bedroom and rest of house, all of course with their own respective room stats.

The feed for the living room rad will drop down from the first floor.

As you can see in the pic, I hope I've covered it. The cold feed to the rear bathroom might be altered slightly, not sure yet.

The question is this:

From studying the proposed install, I have noticed that there is a strong possibilty of reverse circulation through the rest of the house return when the zones are being fed. 5 2way valves are being used, 4 for the zones and one for the HW.

In the diagram, you can see that I have put X's with an arrow next to them to indicate two of the places that I was going to include non-return valves....but now I'm thinking again...

Can I just completely reverse what I have planned, (except of course for the HW feed and return) and have the whole system's zones valves operating soley on the returns to the boiler form the respective zones?

In other words, apart from the hot and cold tap water, is it possible to change the red lines to blue ones and vice versa and just have the flow travelling the opposite way? would that solve the reverse circulation problem?

Any help with this would be massively appreciated as I've never tackled plumbing before so I've spent the last six months researching like crazy and my confidence levels are high. Building regs et al... Even my soldering seems to be coming on a treat.

Sounds like quite a project you're taking on! With regard to reverse circulation the only way to be sure it doesn't happen is to have one common return, all the flow/returns coming from one location in the house. This means each zone is a seperate circuit and doesn't just have a zone valve attatched to the flow pipe going to a rad.

I can't really make much sense of that diagram, it's unclear to me where the boiler/pump are.

It sounds overly complicated to be honest. Awful lot of work involved just to have one rad zones.

How big is the system and what kind of hot water cylinder do you have?

Thanks Andy. I admit that the diagram isn't clear and I think the best of it is in my head. I have no choice but to start again with the complete system see as the old system is a mixture of 8mm, 10mm and 15mm, some of it is blocked and most of it has been bodged over the years and simply doesn't work.

I'm just taking this opportunity to seperate the living room and a couple of bedrooms from the rest of the heating requirements for the house. I will probably leave the heating on 24/7, with the main house stat at night turned right down controlling the most of the house on TRV's, (not the one closest to the stat).

Mainly so that we can have whatever temp we want in the bedroom at night without having to heat the rest of the house. Likewise with the living room.

The guest bedroom can have the same too so that they also can get heat without wasting energy elsewhere.

I admit that it probably is overly complicated for the size of the house, but at leat I'm having fun in the process.

Is it OK to have 2way zone valves at the end of the circuit, ie. on the return just before the boiler?

That way, I'm thinking, when there is call from heat from any of the zones, the pump will supply the whole circuit with pressure, but only the valves on the returns will operate and flow.

I do have built in to it a bypass valve just for good measure and to try to temperature balance the circuit later for feed and return temperatures.

It's a system boiler so the pump is integral and it can be connected either side for feed and return. Obviously taking into account the direction of the pump.

Thanks again.

thanks a lot mate, you don't even know me. I can't make it any worse than idiot who put it in in the first place.

Then rip it all out and let a good plumber start from scratch.
This nrv stuff and MV's at the end of the circuits sounds like nonsense.

Don't worry about Nordio - he's got a curious way of endearing himself to people

Must admit, this is sounding like quite a complicated way of doing it (can't wait for the questions regarding the wiring centre ). Are you sure that a simpler arrangement than an S plan plus is not more advisable?

Apart from anything else, the cost of piping independent circuits will be phenomenal for what appears to be a 3 or 4 bed house.

Nordio said:

Then rip it all out and let a good plumber start from scratch.

Ther obviously aren't any to be found on here, This website just seems to be full of self effacing W*^K£>S.

This nrv stuff and MV's at the end of the circuits sounds like nonsense.

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That's why I was asking the question in the first place, cos it looked wrong to me too.

If all you can do is criticise, then good luck to yas, you can all keep your advice and yer sh!tty website. Thanks for nothing.

watchit said:

Nordio said:

Then rip it all out and let a good plumber start from scratch.

Ther obviously aren't any to be found on here, This website just seems to be full of self effacing W*^K£>S.

This nrv stuff and MV's at the end of the circuits sounds like nonsense.

Click to expand...

That's why I was asking the question in the first place, cos it looked wrong to me too.

If all you can do is criticise, then good luck to yas, you can all keep your advice and yer **** website. Thanks for nothing.

Click to expand...

Calm down mateyboy. I'm not criticising you, just questioning the cost effectiveness of it.

If, based on the harsh comments of one poster on here, you are going to tar us with the same brush then you're doing yourself no favours.

You can put the zone valves on the returns if you want, it's quite common. It's not a sloution for reverse circulation though, it won't help. Also, using non-return valves is just masking the problem. Do it properly and have a common return as I mentioned earlier.

It's difficult to advise on this stuff without seeing the job, maybe you could ask the RGI that's installing your boiler for advice as obviously he'll be onsite and able to view pipework layout.

I agree with andygasman on this. If you want more help on here, then a diagram which indicates the CH circuits alone would help untangle things a lot, as would using recognised plumbing symbols.

Ditch all the exotic controls, fit weather compensation, and save yourself a packet!

TRVs on most [not all] of the rads will do everything else you need.

mysteryman said:

Ditch all the exotic controls, fit weather compensation, and save yourself a packet!

TRVs on most [not all] of the rads will do everything else you need.

Click to expand...

I'd second that advice!

daneski88 said:

If you want more help on here, then a diagram which indicates the CH circuits alone would help untangle things a lot, as would using recognised plumbing symbols.

Click to expand...

I asked first and got no reply. //www.diynot.com/forums/viewtopic.php?p=1677035#1677035