cornish wood burner

That looks like it would warm your space nicely. I was at a recycling yard yesterday and they had a few wood burners there, probably not the most efficient but you might pick up one at a very reasonable price at your local yard that would do for your workshop. I thought it might be worth sharing that, it may not be of interest but no harm done either way.

That looks bad. If your boiler frame is too cold then you will get condensate and tar around the inside as you have. It looks to me that your boiler needs to run hotter with probably more secondary air. Can you tell us your return water temperature?

I think you might be surprised at the cost of a one off. I would get it made in a high tensile steel such as EN16T. Your machine shop should advise you if you tell them what its for. Needs to be right as you don't want any fatigue failures at the base of the male thread. I'm sure you realise it will put a lot more load on things so you need to go carefully.

Can you just use two 3 inch extensions

You would still get the same heat output just the water would be at a higher temperature going back into the boiler. Some water from the flow side would just go around again and the boiler would only need to heat it from 70 to 80 rather than 60 to 80. You would need slightly more flow or a separate pump on the shunt line if you needed to keep the output at 80. Thats the standard BEPV back end protection valve system on our larger biomass boilers. On your system if the boiler output varies as the charge burns then doesn't the water temperature change with it? A BEPV would do a similar thing to your 70 deg start but continue to work all through the burn. We did have a problem with a low return temperature once and found the tubes full of rust and soot. Not quite tar but going that way.

Yes we stack in long lines. Say the cord is 12 ft then our stacks are 12 ft wide and 200 ft long. Miss 6 ft then start another line.

Controlling return temp by demand must be a bit hit or miss I would have thought. Could you not have a shunt system with a thermostat on the boiler return controlling a three port valve to keep the return higher. As you say if the boiler temperature is low then it will give problems.

Anything up to 4 times normal running current I'm afraid. If you run too small a genni then your splitter will pull the voltage down and draw more current than it should. Might end up damaging both machines. As Steve suggests 3 or 4 kVA minimum.

It sounds to me that you have a problem with your set up somewhere. Different woods require different setups and its normally just a question of getting it right for what you are burning. Another avenue to investigate is your boiler return temperature. If it is too low then that may be giving you problems. How do you control your boiler return and what temperature does it normally run at? I don't have the luxury of kiln dried timber so I like to keep my boiler returns above 65 or even 70 deg C to avoid condensation. If your system flow rate can take the heat away then those sort of temperatures might be an advantage for you. Does your boiler manufacturer specify a temperature?

I also notice a difference up through our stacks. The bottom metre is wettest due to lowest air flow, the next 3 metres are drier and the top metre is driest in summer, but in winter after a lot of rain it becomes almost as wet as the bottom. We have found a gap of 6 ft or so works well for us, as it gives good air flow without taking too much space. I cover the top of my own logs, but at work we have many thousands of tonnes stored in 5 metre high stacks, so top covers would be difficult and dangerous to install at that height. If you can cover the top it is obvious best but airflow is also a very important factor. We position the lines at approximately 45 deg to the prevailing wind so it is not only blowing through the stacks but also up the alleys.

Sounds like old hand's might have been

Higher the better I would say. More air flow through so should lose moisture quicker. We stack about 5 metres high. We have too much to cover but if you can it will help

I have the E150 version 2.9 KW and its far superior to the works Karcher of a similar size. The reel and the on board storage are very usefull. I have used it for many full days with no problems so far. May be P150 ?

Hi bvf. Always best to wear a mask if there is a risk of mould spores. Even a disposable valved one with the right spec will be a big advantage in the open. The CO is only a risk in confined spaces, spores will be more of a risk when disturbed, and worse when confined such as in the back of a van so a better mask then perhaps? Good to see the info in this thread being read and hopefully acted on. Continue your study if you wish but I would suggest no more sniffing.

Might be of use if you have no mains power and didn't want to run your genni by night. Alternatively you could feed it from PV panels or windpower then use it to cover the dips in your supply. I expect it would make a big difference to your electricity bill. Anyone any ideas on price?

Not sure if its restricted to dry wood but certainly the danger from pellet silos is well known. I think any enclosed area containing wood can be a danger. This is not really my field, but apparently oxidation of the fatty acids in the wood is believed to be the cause, so presumably fresh wood or pellets could produce CO until the reaction is complete.The reaction increases with temperature so a warmer load of chip will be producing more CO. Symptoms include headache, dizziness, nausea or shortage of breath, some of which have been described on this thread. Never logged the CO from our chip pile but I think it might be an interesting exercise.

Lot of talk about the spores but don't forget the carbon monoxide. Oxidation increases with heat so your fermenting pine could be busy producing CO in the back of your van or chip store. I would expect the clouds of steam and spores seen rising from disturbed wood chip to also contain CO.

Two years on but I think this might be worth discussing. We store our biomass wood chip in a large open shed at anything from 20% to 35% MC. What we normally see is the chip heating up (even if it averages 20% to a degree )and the steam finding a way up through the chip. This causes damp patches on the surface so could be a likely growth area for mould. Not so much of a problem for us as we move it by telehandler but even then on occasions we have felt the need to wear a mask. However if your store in enclosed and you need to enter it to say clear a blockage you should be aware of a couple of dangers. 1 The mould spores could be highly concentrated in the enclosed silo area when disturbed. 2 Potentially worse would be the carbon monoxide from the decaying chip or pellets. To reduce the risks from either, ventilate well before entering a silo, wear a good mask and ideally have a safety line with a second person at the end of it.

Absolutely correct Bob except for the last bit. It has a very good scientific basis. Low fire box/ furnace temperature will give poor combustion. The large wood burners I run burn best/cleanest if they are run hard and I don't see any different principle for the smaller ones. I'm sure that is what Andrew (openspaceman) was endeavoring to find out but his query was not answered.

Sounds like it might even be something to do with wind or some other factor affecting the flue draw. Could this affect your secondary air input and cause your smoke. If your secondary air input is too low why not feed some in higher. Probably not difficult job and I expect it would improve your problem. Primary air under the fire , secondary over it

Bark is a couple of % down on energy and high in minerals so not top class fuel, according to Joseph Binder ( Binder Boilers ) who I met about 10 years ago. Looking back now he gave us some very good info, pity our installers didn't spend more time with him. Never knowingly burnt willow in the boilers but we have had ash melting at one stage in the early days when the Austrians changed the settings remotely. Looked bit like Portland cement and water with no sand. I sometimes burn willow in my Rayburn but funnily enough it doesn't seem to get quite that hot.

We notice the difference when burning slab wood compared to round wood. I'm farly sure that bark has a bit less energy as well

Could you be burning smaller diameter logs so more bark for the same volume of wood. More bark = more ash

I'm not familiar with the boiler you mentioned but I run a couple of larger chip boilers. Smoke is normally due to not enough secondary air in relation to the primary air. Incomplete combustion of the volatile gasses driven off, increase secondary or reduce primary whichever suits the output you require.

As a rough guide for you if you want to move 1 KW from a room at 30 deg C to another room at 10 deg C you will need to move almost 2.5 cubic Metres of air every minute. As Gillsgardening said you need a wood burner designed to do this. Feed your system hot air then the flow drops to a sensible rate.