Advice on installing wood boiler stove.

[lenny]

Good evening

I have attached a Drawing of how I propose to install a wood boiler stove for central heating only. The drawing was based on an installation I visited today installed by plumber a few years ago. The home owner tells me the system works fine and has never had any problems.

The reason I ask for any advice or comments on the installation is that I have yet to find any drawings in various installation manuals with this type of set up.

Thanks

Len

 

[Centralheatking]

Good evening

I have attached a Drawing of how I propose to install a wood boiler stove for central heating only. The drawing was based on an installation I visited today installed by plumber a few years ago. The home owner tells me the system works fine and has never had any problems.

The reason I ask for any advice or comments on the installation is that I have yet to find any drawings in various installation manuals with this type of set up.

Thanks

Len

Hiya,

I have had some experience with wood and straw bale burners. You could try the AECB (association for the environmentally concious building) to confirm what I am going to suggest - they have members doing it. The editor of 'Building for a Future' magazine was building a straw bale system a few years ago.

You need to realize that your fuel source is not exactly controllable in the way gas/elect is. Some wood will burn badly and others burn really well and give out
loads of energy.

This is really where you need to consider installing an accumulator which will
capture the excess heat not being dissapated by the rads etc. - otherwise
you might get -
1. Water overheating in the system
2. Having to 'stand over' the system as you cannot just switch it off
3. Wild variations in heat in the building as the fire in the stove gets fed and then dies down.

You could control the accumulator - or large -ish cylinder with a motor valve to let the excess heat in to the cylinder when excess is detected - conected to a room stat.

You will also get hot water from this arrangement either in total or to be boosted
by an immersion on cold nights.

I have run out of ideas for the time being but if you are really keen I will put some more thoughts up

Yours Centralheatking

 

[quality]

Also don`t over look the flue and ventilation requirement HETAS springs to mind

 

[lenny]

Hi,
Thanks for the comments, the property has no space for an accumulator. We are looking into installing an Aarrow Stratford which has an integrated thermostat. If the system is correctly sized , will this do the trick ?

Have you any comments on the schematic using only 2 tappings on the stove.

Thanks

Len

 

[mark_mc]

This would work, but not the correct way,

If i do a wood burning stove I use all 4 tappings,

Gravity circuit
Radiator circuit (pumped)

1 side of the boiler do a gravity circuit to the hot water cylinder, with your cold feed and vent connected. You can also connect a heat leak radiator if the cylinder is small. On the gravity return pipe fit a pipe stat (set to 45degrees) when this temperture hit it turns the pump on, the radiator circuit. all pipework 28mm copper 22mm vent 15mm cold feed

Another side of the boiler is the radiator circuit, on this fit the pump with check valve and this connect to the bigger flow and return pipes on your central heating. The reason for the check valve is so that when your central heating is on it does heat your wood burning stove.
Fit a drain off at the lowest point

 

[mark_mc]

diagram of reccomend installation,

you may need a twin coil cylinder, the gravity circuit will not work in a mains pressure cylinder the coils are coil in coil

 

[Billy Bob Bob]

this would work, but not the correct way,

if i do a wood burning stove i use all 4 tappings,

gravity circuit
radiator circuit (pumped)

1 side of the boiler do a gravity circuit to the hot water cylinder, with your cold feed and vent connected. You can also connect a heat leak radiator if the cylinder is small. On the gravity return pipe fit a pipe stat (set to 45degrees) when this temperture hit it turns the pump on, the radiator circuit. All pipework 28mm copper 22mm vent 15mm cold feed

another side of the boiler is the radiator circuit, on this fit the pump with check valve and this connect to the bigger flow and return pipes on your central heating. The reason for the check valve is so that when your central heating is on it does heat your wood burning stove.
Fit a drain off at the lowest point

diagram of reccomend installation,

you may need a twin coil cylinder, the gravity circuit will not work in a mains pressure cylinder the coils are coil in coil

he said heating only

 

[tamz]

Generally gravity off 1 side, pumped off the other though that will work ok. Without connecting to a cylinder, although you should as it will be "free" HW, the heat leak radiator(s) should be min 2kw depending on output of woodburner. Fit 2 lockshields to it so it can't be turned off. Fit a metal or glassfibre F&E tank, fit hi/lo stats to prevent overheating and condensation.
The manu's will give you advice. Ring them.

 

[lenny]

Hi

Thanks for the replies, Your right gas man my question was for heating only. I have spoke to the manufacturer and this set up is acceptable. What I did miss off the drawing is a 1.5 bar safety valve.

Thanks
Len

 

[tamz]

Hi
What I did miss off the drawing is a 1.5 bar safety valve.

Where? and serving what purpose?

 

[lenny]

Tams....

A safety valve (PRV) should be fit on the gravity flow from the boiler.

Len

 

[tamz]

Len
Unless i've missed something there is no requirement to fit a prv to a solid fuel open vented system. What is the point? It is open to the atmosphere.
I fitted 4 - 5 solid fuel systems / week for 4 years and still do the odd 1 now and then and have never heard of this one.
The only time a safety valve, as in Nabic, was required on open systems is on ind/ comm stuff for insurance reasons. Domestic was never an issue. Things may have changed in the last year or so but i doubt it. Please point me to your source of information. I'd be interested to know.

 

[lenny]

Tamz,

what would happen if the vent pipe in the loft was to freeze during a cold winter, then your client was to light the stove?

For about 20 min or so extra work and about an extra £15-£20 or so you could fit a PRV.

Down-load a villager manual I'm sure they advise you fit one

Len

 

[tim]

Hi All,my name is Tim
Have two questions first is can i use 22mm pipe on heating side which is pumped and 28mm pipe on the gravity hot water and secondly how far does the copper from the boiler need to be before i can convert to plastic.
Cheers for a very informative site.
Tim