Biomass boiler - almost there!

Well it's been an eventful day to say the least. Installing our domestic biomass boiler has become a journey of discovery for us and our installers Wessex Biomass...

We'd hoped today was going to be the last day of the job...

Yesterday work on the flue was into the roof void with just the external work and making good to do and little else to complete on the system today other than refilling the thermal store and central heating circuit and commissioning the boiler.

The roof work on the flue turned out to be relatively straight forward, around noon a 1000kg of wood pellets turned up and between three of us were restacked in the garage. 130 kg easily fitted in the boiler's hopper. Once the boiler has got our thermal store up to temperature we will get to know how rapidly it consumes pellets and get into a routine of topping up the pellets hopefully weekly or even fortnightly. This will involve emptying a few 10kg bags of pellets into the hopper - I can more or less manage this and it is easier than filling our water softener which is also 10kg bags as the hopper is much more accessible.

With the boiler and system controls all programmed we were ready to fire it up and much to Steve our installer's satisfaction this went without a hitch. Amazing bit of kit!!

We were then instructed on the maintenance routine for the new appliance. This makes sense to us as we are used to a wood burner we have in our sitting room - the boiler is a lot easier to look after than this. The integral ash store should only get full every 1450 hours of running time (months).

The euphoria was not to last as it became apparent something was a miss elsewhere in the system...

The boiler was over heating so more head scratching for Steve to work out why it wasn't transferring heat to the thermal store. We'd already had fun and games trying to explain the pipe work for the thermal store cylinder to ourselves before it was reworked to give optimal benefit from the biomass boiler. It will just keep the water thermal store hot so it is there to heat on demand for hot water or pumping round the radiators for space heating.

Incredibly the radiators were getting rather warm despite the thermal store not getting up to temperature - how so? The answer was conduction via the return circuit from the boiler to the radiators of which the thermal store is really a very large kind. Turned out our oil boiler had been plumbed in backwards so, with no consequence, the water flowed in the opposite direction to that intended. However, the assumption was made based on this 17 year old mistake as to which pipe was flow to the cylinder and which the return...

So we'd ended up with backwards plumbing and two pumps opposing one another... Luckily one of them could be inverted to cure the problem temporarily but corresponding work required tomorrow also to the cylinder to make it work efficiently...

Glad to have realised the problem. Wessex would not have left us until all is working satisfactorily but hard to imagine how it would have been spotted and rectified if we'd just gone for an updated oil appliance. And I'd been joking all week that everything we try and do in this house is a problem and not what you expect to find - some houses, lovely as they are, seem not to want to be altered! Either that or some real cowboys were in on the development...

But...We have hot water tonight!!!!

Claire

Location:Wiltshire