Wood Burner Heating System Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[PSBenson]

Hi
Currently living in New Zealand, and would like to install a Wood Burner with a radiator heating system to it, however may sound simple enough.. but doesnt seem to be the case here in North Island. The plumbers Ive asked say no can't do that won't work...!

All I want is my wood burner to heat the water (back boiler) install a pump that would circulate the water via radiators also heat my imerssion water tank also. Can anyone give me a a full breakdown of what I'd require to make this happen. Or point me in the right direction where I cold get a full diagram of how to set this out. I had a soild fuel burner installed in 1982 working on the same princple surely this is not rocket science.. but seems to be here.. the plumbers say can't install in-line pumps.. must be gravity for the hot water etc. Any help much appreciated.

[Bob Plum]

Boilers that run hot water and rad's are availabe here that burn any of the normal fuels, including wood.
As with any solid fuel boiler, it is normal to connect a loop somewhere to dump heat because they cannot be completely turned off as can electricity, gas and oil burners. If there is no open loop to dump heat when there is no demand for heating water or rad's, the water in the boiler, boils. The usual place to dump heat is through a small radiator placed where extra heat will not be a problem (I have even heard of one being placed in an unused loft, but a large landing or un- or rarely used room is more normal), or to use a towel rail in the bathroom - the problem with using a towel rail is that they can get unbelievably hot - dangerously so.
The circuits are all the same, irrespective of fuel (except the open loop to dump excess heat) - the water does not know what is heating it.

[TW]

I think the problem could be the clean air rules in New Zealand now, under the new guidelines (depending on where you live) there are only a few fires that can have a wetback or water booster fitted. They have a maximum output of around 3kw at best which is not really enough to run a radiator let alone two or three. There is a metro fire that you can get around an 8kw "boiler" for, that would do a better job but again it would depend on where you live. If you are in the country on a 2 hectare land area then the legal requirements are greatly reduced and you can fit almost any log fire.
I have been looking at doing the same as you but I live in Canterbury where the clean air rules are the toughest and the fire with the biggest wetback I have found that I can fit here is the Pyroclassic. It has a 3.5kw wetback, so I have been looking at fitting solar heating to preheat the water in the cylinder so the heat from the fire doesn't have to start heating the water from cold. The problem with that idea is when we need the heat the most (at night) the sun won't help. The only other real option is a pellet boiler and they start around $7000.