s plan with wood bolier

[underpar12]

hi
can anyone help with a wiring diagram for a s plan with the bolier being a wood burner.many thanks.

 

[Guest123]

The s plan configuration will be the same as for any other type of boiler.

You will need to check the wood burner manuf's instructions to see if there are any particular requirements to the model you have, such as pump control etc.

 

[chris murphy]

"Hello",


I am a Heating Engineer - I have recently been Helped by topquark on here regarding an `Unusual` Programmable Room Thermostat Wiring question - I hope that My comments below will Help with this Subject / Question:



Wood Burners for Central Heating Systems have special requirements regarding the Pipework and Controls for SAFETY Reasons.


I cannot go into the Technical / Safety Details on here as ANY Misunderstanding / Misinterpretation could cause a VERY Dangerous situation to exist regarding the Heating System Pipework and / or Controls.

Here are just a FEW comments applicable to Central Heating from a Wood Burning Appliance:

IF this System has been Installed by a Heating Engineer You should get confirmation from them that ALL of the Wood Burner Installation Instructions relating to the Heating System have been adhered to - That is a MUST - I would ask for that in Writing - AND I would want a Copy of the Wiring Instructions for the System FROM the Manufacturers of the Wood Burner - Because the Pipework configuration and Controls WILL have requirements that a Gas or Oil Boiler Heating System will NOT have.

Think about it this way - When Thermostats are Satisfied on a Gas or Oil Boiler the Gas or Oil Burners are turned Off - A Wood Burner cannot be `Turned Off` in the same way - The Heat MUST be `Accommodated` / Diverted to a Heat Dissipating Bypass - when Circulating it around the Radiators / Heating System / Hot Water Cylinder Coil is NOT required - Otherwise the Pipework connected to the Wood Burner would become TOO HOT - with Disasterous results !

The Pipework and Controls / Wiring WILL be Different / Additional to that of a Gas or Oil Boiler `S Plan` Heating System.

I would advise Caution regarding this - Incorrect Pipework OR Controls Wiring could in some circumstances turn a Wood Burning Appliance Heating System into a VERY DANGEROUS situation - With the possibility of Over Pressurisation of the Wood Burner / Pipework and in Extreme circumstances an EXPLOSION of STEAM - Which would `Escape` and IMMEDIATELY EXPAND TO 1600 TIMES the Volume of the Steam - Catastropic in most Domestic situations !


While that is an Extreme Circumstance - IF the Wood Burner and Heating System has NOT been Installed by a Heating Engineer I would definitely suggest that You do NOT Wire the Controls - IF it HAS been Installed by a Heating Engineer They should be able to Supply You with the Manufacturer`s Installation Instructions where You will be able to SEE any Additional Wiring Requirements for the `Control` of the Wood Burner / Any Bypass Pipework Controls / High Limit Thermostat Bypass Valve etc. that are required to make using the Wood Burning Appliance SAFE.

IF the Heating System is of a `Sealed Type` - There should also be a Temperature Relief Valve / Pipework and a Pressure Relief Valve / Pipework - to allow the Pressure in the System to be Discharged to a SAFE External Position IF any Over Pressurisation occurs - Because this may NOT always be at the Wood Burner Position - It MUST be established that the Wood Burner itself CANNOT be Over Pressurised - For example when the Zone Valves Close.

There are also Safety Issues regarding an `Open Vented` Heating System connected to a Wood Burning Appliance - One simple example is that there should NOT be an Expansion Pipe that `Discharges` [If the System Water Expands] into a PLASTIC Feed and Expansion Tank.

Because of what I have written here being `Checks` that should be carried out by an EXPERIENCED Heating Engineer - An Engineer that has Experience of Wood Burning Appliances - OR who is `Confident` that they can Verify that the Manufacturers Installation Instructions have been adhered to - I really cannot recommend that You get involved in Wiring Up the Heating Controls.

I mean this in the Nicest Possible Way - You really could end up with a `Explosive [Steam / Pressure] Situation` on your hands !


Regards,


Chris

 

[Dunc]

Can't say I've ever seen a S-Plan connected to a log burning stove. As Chris says they're a very different beast to a regular boiler and great care should be taken to ensure that in the event of power loss the heat has somewhere to go. This is obviously the responsibility of the person plumbing the boiler and a sufficient set of gravity fed radiators without TRVs would be in place to dissipate the heat if the pump failed. Most systems I have done are hot water priority. Once the stove is lit the cylinder and heat leak rads will heat up via gravity. Once the hot water has hit it's set temperature the cylinder stat turns on the pump which transfers the heat round the central heating circuit. I have done other sstyles of system but they are based around a neutraliser and involve multiple pipe stats.

 

[Lofty]

Hi Guys,
I've soon got a wood burning cooker / boiler (Esse) to wire in a new build that will only be heating the DHW only and the plumber has fitted a neutraliser and one (1) 2 port valve.
There is of course a cylinder stat which will control the valve already fitted and the system will be complemented with a solar system as well for the DHW, the solar system is being installed by another contractor.
The schematic shows a a single pipe stat on the Esse but this controls another 2 port valve that is not fitted. I think that this is wrong and that there should be the second valve but the plumber / heating eng says not but has no idea what to wire the pipe stat to 'possibly the pump' he has suggested.
Any help on this would be appreciated, after reading the above posts.

Cheers,
Lofty

 

[chris murphy]

"Hello Dunc",

Thanks for confirming that a Wood Burning Appliance for Heating and Hot Water MUST be treated completely differently to a Gas or Oil Boiler in terms of the Pipework Design & Sizing - Controls and Wiring / SAFETY Systems etc.

These considerations require the involvement of a Heating Engineer - Experienced in Wood Burning Central Heating Appliances - BEFORE any Wiring of Heating Controls is even contemplated.

Because anyone Wiring a System that has been Incorrectly Designed / Incorrectly Installed by the `Heating Installer` could be Enabling a VERY DANGEROUS situation to occur I would HAVE TO Suggest that it should NOT be even attempted without VERY RELIABLE Confirmation from a Heating Engineer who is experienced on Wood Burning Central Heating Appliances that the Appliance and Heating System Pipework and Controls have been Installed CORRECTLY - with ALL necessary SAFETY CONTROLS / Heat Dissipation System.

I am NOT trying to exhalt the Importance of a Heating Engineer above an Electrician here - Although I do feel that the involvement of one is an absolute MUST - A Serious Error in the Appliance / Heating System Installation could cause the VERY DANGEROUS Situation that I briefly described in My previous Post.

And whichever way You look at this the Electrician would have been the Person who `Enabled` the Dangerous Situation to occur because of NOT knowing about the possible serious Errors on the Heating System / Appliance Installation - Even though they would NOT have caused the `Fault`.

My `Motive` for Posting these comments on here is to Give something back for the Help that I received from topquark - and to hopefully prevent the Questioner / underpar12 from POSSIBLY getting into a VERY Dangerous situation / Putting the Householder / Heating Installer into a VERY Dangerous situation when the Central Heating is `Fired Up` [ Wood Burner is Lit and Heating Up].

I hope that My Post will be viewed as it is meant - NO amount of Electrical Knowledge can `Guarantee` that your Wiring would NOT `Enable` a Very Dangerous situation IF the Wood Burning Appliance / Heating System has been Installed in a Dangerous `Design` / Manner - sometimes `Dangerous Defects` are NOT Obvious at first glance to even Heating Engineers viewing other People`s Installations.

Chris


P.S. Dunc I hope that You don`t mind Me using My Reply to You to add more comments about this Wood Burning Appliance and the Wiring of the Heating System.

 

[Guest123]

Surely the onus is on the plumbing installer not the spark to ensure that all neccessary pipework & heat sinks are in place for thr particular heating appliance.

 

[chris murphy]

"Hello Lenny",

You are obviously correct in the statement that it would usually be the Incorrect Pipework / Heating System / Appliance Installation - or the Omission / Incorrect Installation of Safety Controls that would cause the VERY Dangerous situations that I described.

BUT - Because of the possible DANGER of an Incorrectly Designed / Installed System / Appliance - I would very strongly urge any Electrician to REQUIRE the Wiring Instructions FROM the Appliance Manufacturer of the Wood Burning Appliance - Specifically regarding the Heating System AND Safety Controls - And to then ENSURE that ALL of the Noted Controls / Safety Devices are Installed as described - IF they are confident in checking this ? - As taking this upon themselves probably would cause them to be `At Fault` in the event of any `Dangerous Event` - Otherwise I would suggest NOT taking on the Wiring of the Appliance / Heating System.

It is because of the DIFFICULTY of expecting anyone EXCEPT a Heating Engineer who is ALSO experienced in the Installation of Wood Burning Appliances for Heating Systems - to carry out those System Design & Installation `Checks` and Safety Device / Control `Checks` that I have detailed all of My `Concerns` in reply to the Original Questioners Post.

As a Heating Engineer I would NEVER even attempt to `Check` a `Complicated` Electrical Installation - which for Me means anything with more than One Circuit ! - as I would NOT have enough Theoretical / Practical Knowledge - And for that same reason I would suggest that an Electrician should NOT even attempt to `Check` this type of Heating System before carrying out the Heating System Wiring that We are writing about here.

Even a Heating Engineer who had no experience of Wood Burning Appliance Heating Systems would have to VERY Carefully Inspect the Heating System Controls and Safety Systems / Controls for the Correct Installation of those and the Pipework Design / Installation - AND They would DEFINITELY Require the Wood Burning Appliance Manufacturers Installation Instructions - As there will be differences in the Safety / Heat Circulation / Heat Dissipation Methods between these Appliance Systems and `Normal` Gas or Oil Fueled Heating Systems.

On the basis of these and My previous `Comments` how would the Electrical Professionals on here view the Wiring of this type of Heating System - WITHOUT the Wiring Diagram from the Wood Burning Appliance Manufacturer - Which I assume is NOT available to the Questioner - as otherwise they would not be requesting Wiring Details on here.


I hope that My Comments may be `Useful` - I really am trying to prevent any of the Electricians on here from finding themselves in a VERY Compromising situation regarding Wiring a Wood Burning Appliance Central Heating System - and possibly `Enabling` a VERY DANGEROUS situation to Immediately Exist.


Chris

 

[chris murphy]

"Hello",

Further to My recent Posts:

In one of which I referred to the possibility of a Heating System being of the `Sealed Type` - Because I was writing about ENSURING that the System / Wood Burning Appliance could NOT become `Over Pressurised` - For example by the Incorrect Siting of Zone Valves on the System - Or the Incorrect connections for the Expansion and Cold Feed Pipes, I then went on to comment about `Sealed Systems` and the requirements of Temperature and Pressure Relief Valves / Pipework.

Having Re-Read that Post I must CORRECT My comments to state that the MAJORITY - If not ALL Wood Burning Central Heating Appliances are NOT suitable for connection to `Sealed` Heating Systems.

Because I was trying to mention MOST `Safety Issues` relating to these Wood Burning Appliances and I have often written about the Safety Requirements for Sealed Heating Systems - I just `Slipped Into` also writing about `Sealed Systems`- as I would do If writing about the Safety Issues on any Heating System.

These `Sealed Systems` are NOT appropriate for connection to Wood Burning Appliances - Unless SPECIFICALLY stated by the Appliance Manufacturer - which would be VERY Unusual.

I am writing this message because I have noticed that I am Unable to Edit My Original Post that contains that paragraph on Sealed Systems - Is it NOT possible to Edit a Post after a Short period of Time ?

Although this may not have been noticed - I wanted to CORRECT what I wrote in case anyone did find a Wood Burning Appliance connected to a Sealed Heating System.

In that case some SERIOUS Doubts should come to mind and Inspections should be carried out and most Important of all - The Appliance Manufacturer should be contacted to ASK about the `Suitability` or Otherwise of this - As in MOST / If not ALL cases this would be INCORRECT / DANGEROUS !

Chris