Changing a combi system to a y plan

[monkey5]

evening all,

been asked to convert a combi to a y plan system basically because they have to run off a hell of alot of water before it gets hot, due to boiler one end of house and kitchen the other.

is this a simple task if so whats the best way to go about it.

i havent done many central heating systems so not that clued up on this subject.

thanks in advance

wayne

 

[NozSpark]

Personally I'd do it as a "S" plan + with Honeywell components

that is..

a 2 channel programmer

a roomstat

EDIT.. a cylinder stat

2 x 2 port valves

with a good look at the diagram you'll figure it out, but use your orange wires to feed the heating demand input of the boiler (LR on a Worcester Bosch)

HTH

 

[Lurch]

It depends on how the system is piped up currently, but that fact you're asking I'd say you need a plumber.

What makes you think it will be much quicker with a conventional system though?

Personally, I'd check the boiler settings, some have a setting to keep a reservoir full of hot water for these circumstances.

Failing that, I'd be inclined to fit a cylinder on the combi, or is this what you were asking how to do? This is relatively easy, just need the external controls wired off the room stat terminals of the boiler. Some will require you to wire the controls separately from a separate fused spur with a relay between the 2.

Few more details would be handy for a fuller answer.

 

[monkey5]

cheers for quick replies,

i havent seen system yet am going in next couple of days, it was a plumber whos asked me to look, he just said it needs changing to y plan and wants me to do the wiring up so will post more details when i know, just thought id get a few ideas before i go.

cheers wayne

 

[Lurch]

Oh right, well if the plumber is already on the job then I don;t see what the issue is, just wire the Y plan. Use the wiring diagram under the heading 'Y plan' in whichever set of easily obtainable online instructions or the ones in the equipment supplied by the plumber.

 

[jl-heating]

i use a y plan up to 60,000 btu anything over we use a s plan due tothe size of the connections on the 3 port valve.

from the sound of things you will be removin the combi and fittin a heat only boiler ??

another way is to convert the boiler into a system boiler and pipe in a hot water cylinder, also possibly pipe in a secondary return for instant hot water at every outlet..

endless options really.... moore info needed .

 

[Doc Hudson]

You been busy JL? I don't recall seeing many post recently. But it is very good to see you back tonight.

Doc H

 

[steptoe]

kinda with JL on this,

if it is taking ages for the hot water to reach the tap having a tankful wont necessarily make it any quicker, unless you have it constantly pumped in a loop,

done one a while back with the pump on a timer.

 

[monkey5]

i use a y plan up to 60,000 btu anything over we use a s plan due tothe size of the connections on the 3 port valve.from the sound of things you will be removin the combi and fittin a heat only boiler ??

another way is to convert the boiler into a system boiler and pipe in a hot water cylinder, also possibly pipe in a secondary return for instant hot water at every outlet..

endless options really.... moore info needed .

spoke to plumber bout what he's actually needing, he's going to put a hot water tank above kitchen/bathroom, so needs the combi to fill cylinder when needed, he's said about a y plan. im really having a block, il be honest ive only done 1 central heating system so not really got a clue so any help would be appreiciated.

im doing this for a plumber and also some work for a builder who i know is keen on giving me more work so dont want to mess up on this

many thanks wayne

 

[NozSpark]

Without even knowing the make of valve that's being used we can't even point you in the right direction of the diagram.

 

[Lurch]

Without even knowing the make of valve that's being used we can't even point you in the right direction of the diagram.

They're all the same, but as I said before, if it's a complete Y plan with a combi as the boiler then it sounds a right odd heath robinson affair. Without want to cause offence, I'm not convinced either you or the plumber is using the right terminology and is actually going the right way about this.

If I've read it wrong then, as I said before, wire the Y plan but rather than LNE to the boiler on the diagram you need to go to a relay which then opens and close the external controls contacts on the boiler as neccesary. There are probably other fancier ways of doing it and I would use the relay way as a last resort but without knowing the boiler I can;t be any more specific.

 

[kme]

Why not just run a new flow to the new water tank, with a tank stat and 2 port valve - with timer if req`d.

Save messing with the existing - its just a bolt-on (like adding a zone)......

KME

 

[monkey5]

Why not just run a new flow to the new water tank, with a tank stat and 2 port valve - with timer if req`d.Save messing with the existing - its just a bolt-on (like adding a zone)......

KME

this sounds a good idea, how would it be wired?

sorry if this sounds basic... :coffee

 

[bluetobits]

Why not just run a new flow to the new water tank, with a tank stat and 2 port valve - with timer if req`d.Save messing with the existing - its just a bolt-on (like adding a zone)......

KME

Would this not cause the rest of the heating system to warm up with a demand calling from the two port valve? Might be wrong. :C

 

[Lurch]

Would this not cause the rest of the heating system to warm up with a demand calling from the two port valve?

Yep.

 

[kme]

Gawd.

Right. Simplicity, this is.

you will need:

2 no. 2 port valves ( for zoning).

Manifold the flow pipe into the inlets of BOTH 2 port valves - one of which re-attaches to the CH flow pipe.

The other attaches to your NEW flow pipe.

The blue wires from BOTH are commoned to neutral.

The green & yellow wires from both are commoned to earth.

The grey wires are commoned, as are the white ones. These are wired in series with the boiler "call for heat" signal wire.

This should leave a brown wire from each.

The brown from the 2 port valve in the original pipework takes the room stat "call for heat". (live feed)

The brown from the water tank feeder valve goes, via any timeswitches, tank stat, etc. , so that it gets a live feed when the tank needs water.

My apologies. I didn`t realise I had to add the modification required to the original set-up.

 

[steptoe]

Gawd. Right. Simplicity, this is.

you will need:

2 no. 2 port valves ( for zoning).

Manifold the flow pipe into the inlets of BOTH 2 port valves - one of which re-attaches to the CH flow pipe.

The other attaches to your NEW flow pipe.

The blue wires from BOTH are commoned to neutral.

The green & yellow wires from both are commoned to earth.

The grey wires are commoned, as are the white ones. These are wired in series with the boiler "call for heat" signal wire.

This should leave a brown wire from each.

The brown from the 2 port valve in the original pipework takes the room stat "call for heat". (live feed)

The brown from the water tank feeder valve goes, via any timeswitches, tank stat, etc. , so that it gets a live feed when the tank needs water.

My apologies. I didn`t realise I had to add the modification required to the original set-up.

I thought this was a help forum,

NOT

a teach you how to forum.

maybe we should start charging and after 5 wonderfully alcohol fuelled days you too can be a part P approved Gasafe installer,

simply send

 

[monkey5]

I thought this was a help forum,NOT

a teach you how to forum.

maybe we should start charging and after 5 wonderfully alcohol fuelled days you too can be a part P approved Gasafe installer,

simply send

 

[kme]

I DO know what he meads, Monkey; I thought the same thing after reading the previous comments - why the hell do I bother?

I didn`t realise I had to provide step-by-step; I was of the impression that a shove in the right direction would be enough.

My explanatory post almost read " do your own soddin thing then!" - but I`m "blessed" with patience (too much, Mrs. KME says, until its bedtime...... )

I AM annoyed that I had to write step-by -step; this ought to be either second-nature to you, or you shouldn`t be attempting it.

KME

 

[monkey5]

Sorry KME didnt mean to annoy. apprieciate your help very much,

cheers wayne