Zero carbon

By pure coincidence on 'central heating day' (http://news.bbc.co.uk/1/hi/magazine/8283796.stm) we fired up the wood pellet boiler, so with our electricity supplied via renewable sources and now our heating from burning wood, Hillside can safely be classed as Zero Carbon!(okay, so there is embedded energy in the various materials, but from a heating & hot water perspective it is minimal so the house can be classed as zero carbon).


My initial concerns about being an early adopter of domestic biomass heating have largely been put to rest. Time will tell if maintenance proves to be an issue.

The Ecoflex boiler was very easy to commission. The first challenge was to convert the controls menu on the boiler into English from the factory set German, but this didn't take long. A few minor tweaks on the controls options and we were off, hitting the start button on the boiler. The screw feed auger then started turning to transport the pellets from the hopper to the boiler, but as it was the first fill of the auger it kept timing out as the boiler wasn't sensing any pellets arriving. 20 minutes or so, and several overrides later, and the pellets started dropping into the boiler, and a few minutes after that we finally got ignition. A problem with an airlock in the hot water circuit meant some work by the plumber to get the circulation working, but once that was resolved we had hot water and heating being delivered to the house.

A couple of minor teething issues have cropped up though that I need to resolve:

1. The auger feeds a ribbed piece of hose that directs the pellets into the boiler burner. Whilst it's a a fairly steep angle it was originally installed with a slight sag in it. This, and the internal ribs in the hose, resulted in pellets collecting partway down the tube causing the boiler to lock out due to no fuel. We'll have to modify the auger/hose arrangement to ensure the hose is as straight and steep as possible, in the meantime we've tied it inplace and this seems to be doing the trick.
2. The boiler setup provides hot water as a priority and only supplies heating once the hot water demand is satisfied. I can see this could be annoying at times so need to see if there is a way to have the hot water and heating circuits running at the same time - it may be I have to call the technical guys at Nuway.

Other than that though we're really impressed with the boiler and it's controls. It'll take a while getting used to the advanced system, with weather compensation (i.e. the heating temperature is linked to the external temperature) and night setback, plus the separate controls for the underfloor heating circuits, but should give us a very efficient and controllable heating system.

And best of all we've cut our use of fossil fuels - bring on the rise in oil prices!