solid fuel boiler with gas c.h. system

[will4]

the plumber tells me it is very difficult to have a solid fuel stoves with a back boiler integrated into a gas central heating system, ideally i would like to heat the house on solid fuel, but on the odd occasion would like to switch back to the gas sytem, and vice versa. is this really that difficult and expensive? thanks

 

[sydthebeat]

AFAIK, the two systems are not compatable, as the gas system is pressurised, whereas the solid fuel system isnt.... i think its a case of either or...

 

[xt40]

i been looking into this recently . ive oil with a mix of ufh and rads and want to add a wood stove.


its hard to get specific info even on the web but ive come to the conclusion that the only advantage of the sealed systems (red vessel in HP) that are almost universal nowadays is that none of the ch system water that youve burned oil/gas to heat is lost back into the cold water tank through expansion which i suppose makes them a bit more efficient then an open vented (unpressurized) system. i doubt the difference is huge.

oil/gas burners heat the water to fixed temps - approx 55-75 degs and switch off automatcally and instantly when the reqd temp is reached which means the pressures are also limited to <3 bar. wood fires on the other hand offer no/slow temp control and could potentially boil the water creating huge pressure in the pipes . power cuts for example are very dangerous as the pump will stop working. the alternative system is the the open vented model which lets the excess pressure out of the system automatically. this is the way that all ch systems with back boilers or >10 years old are designed so its nothing particularly radical.

im going to change mine over which means adding a second baby water tank in the attic which will continually top up the ch system. two pipes run from this to the ch loop in the hp. one lets water in and the second pipe diverts any water lost through expansion back into the top of the mini tank. its not a huge job or particularly expensive.

 

[gipimann]

Will4, I converted to gas central heating several years ago, and at the time of conversion, the installers made a point of disconnecting the heating system from the back boiler, saying that I could not have the two systems (even though obviously I wouldn't have used both at the same time!). I had been able to have both oil-fired ch and a back boiler system (again, not in use at the same time).

 

[xt40]

i see no issue in using both at the same time. the gas simply wont fire as the water is already to temp from the bb.

 

[Brianne]

When I bought my new house a few years ago, gas central heating was the heating provided by the builder. However, we persuaded him at a hefty price to put in a back boiler that would run off the sitting room fire. He was reluctant but it works fine. Basically, if the fire is going and the house is at the required temp, the gas will not kick in. We previously ran a very successful dual system with oil and I wanted to keep getting value from a fire . However, I remember that we had to get a more expensive boiler to run the dual system with gas. It will never pay for itself but I like to think that I can be independent of gas if needed!!!