Combi wired up to a unvented cylinder

[tamz]

i have been to jobs when people have adjusted wires to suit themselves, sometimes it even works! problem is for the person following, best to keep as close to the design as possible

That is why you should learn what switches what and not depend on the standard wiring diagrams.
There are many ways to wire a heating system depending on who does it. Heating systems on new build where it is wired by the site electrician will definetly not follow a std diagram. You will open a joint box to find a pile of three cores. Easy enough to trace if you know what to look for.

The combi and unvented is not a normal thing you will come across often but they are fitted depending on the layout of the house.

 

[fuzzy]

i agree that people can learn to wire by just looking at the diagram and therefore not really know whats going on!! its like painting by numbers. that ok when first fitted but they should know what it does as well as following a simple diagram. that said why do electricians not follow a diagram, they should as often i will follow an electrician and theyve just done it their way and its difficult to suss out, and often its wrong

 

[tamz]

why do electricians not follow a diagram,

Because they (should say some) know what swiches what. It can be wired any way they like as long as the end result is the same.

An S plan is easy. Just learn this.There are a couple of minor variations but basically
HW on at clock through cylinder stat common, call to brown (motor) of valve, miroswitch makes and sends power to boiler (SL)/pump. The heating is the same but through the roomstat.

A Y plan is a bit different and harder to explain as there are 2 microswitches and a resister and diode.

 

[fuzzy]

i disagree, they shouldnt wire it anyway they like, they should wire it the correct way, thats why we have standard ways of doing thing, its not everyone please theirselves.

i know perfectly well how to wire systems, ive been doing them years, there appears to be more wires on an s plan but your correct they are pretty straight forward. Y is only hard to explain for those who struggle to understand it, i find it pretty easy

 

[Drew7779]

A combi or any boiler is just a heat source , it can be wired up in many different ways. The combi/cylinder option is good as you get downstairs hot water instantly and economically and good showers upstairs most combi boilers are not great when another tap is opened or a toilet flushes etc .

 

[GrahamM]

i disagree, they shouldnt wire it anyway they like, they should wire it the correct way, thats why we have standard ways of doing thing, its not everyone please theirselves.

i know perfectly well how to wire systems, ive been doing them years, there appears to be more wires on an s plan but your correct they are pretty straight forward. Y is only hard to explain for those who struggle to understand it, i find it pretty easy

With you on that fuzzy. It is a simple process to follow the wire diagram and then the next guy that comes along to a fault can suss it out in minutes without having to trace all the wiring back before starting to look at what he is there for in first place.
Makes life easier on everyone!
An old contracts manager I know would insist that all the systems fitted under his watch followed the wire diagram. Would not accept it any other way as he new fine well would save his lads time in long run trying trace faults later on.

 

[tamz]

They have been trying to get heating systems wired by numbers since the old ACOPs days. It will never happen. Electricians (especially on sites) will always wire it to suit themselves.

 

[fuzzy]

there have been many attempts to simplify the systems and standardise them, yes electricians seem to want to just do it their own way. we should standardise will it happen? prob not but i always insist on following the common procedure

 

[migoplumber]

forget about microswitches and complicating your life. i presume you have a seperate valve for your ch side.
use your unvented cylinder stat to control the s plan valve direct to the cylinder. (brown and orange linked via cylinder stat)
nice and simple.
shaun