installing a back boiler oil link up in a bungalow, anyway around it?

[Mr Flux]

Hay guys i have never attempted a back boiler oil link up before, i have a customer who has purchased a back boiler wood burning stove and is looking to link it up 2 the oil heating to heat the water and rads! Only problems is that its a bungalow and the hwc is on the same floor as the stove so have no way of installing a gravity circuit to the stove! i was thinking of just fully pumping the system and linking the flow and return from the stove into the boiler flow and returns just where they enter the building (obviously installing all the necessary non return valves! Obviously doing it this way is abit dodgy incase of power faiure and the pump fail to operate, causeing the system to pump over into the f &e but i cant see this being a major problem??? any advice guys, has any1 installed a back boiler which is fully pumped????

 

[Best]

You need to take care! Why can you not have gravity to cylinder in a bungalow? Can you take the return below floors? Or are they solid?

 

[ecowarm]

You cant install a solid fuel boiler without having a gravity circuit to get rid of excess heat in the event of power outage.
There are ways to do this correctly, "H2panel layout 8" is one for a bungalow with a buffer located in the loft, Google it

 

[Mr Flux]

You need to take care! Why can you not have gravity to cylinder in a bungalow? Can you take the return below floors? Or are they solid?

Yes the floors are all solid, would be abit of a nightmare! explain what you mean exactly, as a would need to take the flow up into the roofspace and down into the hwc that wouldnt work on gravity???

 

[Mr Flux]

You cant install a solid fuel boiler without having a gravity circuit to get rid of excess heat in the event of power outage.
There are ways to do this correctly, "H2panel layout 8" is one for a bungalow with a buffer located in the loft, Google it

thanks will check it out now!

 

[Best]

Yes the floors are all solid, would be abit of a nightmare! explain what you mean exactly, as a would need to take the flow up into the roofspace and down into the hwc that wouldnt work on gravity???

Taking the flow higher than the hot cylinder before dropping down to top connection of coil is totally okay, - providing the cylinder is raised a bit & that the expansion tank is well above flow pipe. Flow must rise to vent pipe & fall from it to cylinder. It is actually an advantage to have the connection above cylinder, even in a house.
Only problem in a flow pipe going over the roofspace is you get the heat of cylinder reversing to fire, when fire is colder.

 

[Mr Flux]

You cant install a solid fuel boiler without having a gravity circuit to get rid of excess heat in the event of power outage.
There are ways to do this correctly, "H2panel layout 8" is one for a bungalow with a buffer located in the loft, Google it[/QUOTE

Can only see a diagram for a bungalow incourprating a unvented system into the link up!

 

[Mr Flux]

Taking the flow higher than the hot cylinder before dropping down to top connection of coil is totally okay, - providing the cylinder is raised a bit & that the expansion tank is well above flow pipe. Flow must rise to vent pipe & fall from it to cylinder. It is actually an advantage to have the connection above cylinder, even in a house.
Only problem in a flow pipe going over the roofspace is you get the heat of cylinder reversing to fire, when fire is colder.

Thanks for eliberating on that best! Idealy you would be looking a double coil cyclinder then!

 

[Best]

Thanks for eliberating on that best! Idealy you would be looking a double coil cyclinder then!

Always a double coil cylinder to prevent other gravity or pumped circuits mixing, - unless you are using some sort of neutraliser, or thermal store.

 

[jonmanty]

Flux

Its a completely unsafe installation that you are describing.

The only way that you may be able to achieve a link up in a bungalow is to get the cylinder well up in height above the solid fuel boiler, possibly in the loft space - however that may present problems with siting the cisterns.

There are normally two accepted methods of connecting the two boilers together, the H2 panel as described or a Dunsley Baker Neutraliser. In both cases the there needs to be a fail safe to allow heat to dissipate from the boiler in the event of power supply cut off, this is achieved by positioning the cylinder and a heat leak radiator at sufficient height above the solid fuel boiler to permit effective gravity circulation. Also remember that it's the difference in height between the centre line of the boiler and the centre line of a cylinder or radiator that creates the circulating pressure in a gravity circuit so having them at about the same height will not work.

Correct link ups to do them well and safely are not a job for the faint hearted.

Jon

 

[Best]

Cylinder does not need to be extremely high in a bungalow. In an ideal world it would be well above the fire - as in a house with cylinder upstairs, which would prevent back heating from cylinder.
If the cylinder is raised at all, with the returns & flows all highest at coil, it will work.
Obviously keep it up as high as reasonably possible. Most are just raised about max 600mm from floor on wrap around back boilers, but depends on what height the stove is in your case.

 

[jonmanty]

Minimum centre to centre height in MI is normally around 1.0m on a very short run. It will work with less height but won't be capable of dissipating sufficient height in the event of overheating on a banked fire, therefore additional height to create adequate flow will be required.

 

[Nordio]

Why the need for a gravity circuit?
Just fit a metal f&e and let it steam the loft on the few rare occasions it might boil. Let the pump do the rest.

I fitted a big fan assisted 40kw multi fuel solid boiler in a gaffe a while back and just instructed the guvnor to lash a bucket of water into the fire box if it boils. He seemed happy enough with that.
I demonstrated it to him a few times when it went into china syndrome. Its no big deal.

 

[jonmanty]

Bit frightening for the customer with a 7kW, possibly 12kW appliance boiling away, they aren't usually to pleased.

Besides there shouldn't be any valves pumps or the like in the main primary circuit on solid fuel as an uncontrolled heat source because they can block as its normally providing the vent pipe route as well.

 

[Nordio]

Its not worth going to a lot of hassle over. A dry burner is a better option in many cases.
Fan assisted multi fuel jobbies in the garage are the way to go. Then no fuel to carry inside.