Life in a Dol house
2016 - Week 41
How to be an instant expert
We seem to have drifted into winter this week, at least a month earlier than last year, with the first snow on the top of the Dinaric Alps visible on the mainland, some 70 or more kilometers to the east.
With that in mind I had a discussion with my friend Cvjetko, the master builder, about moving the chimney from my wood burning, water heating stove, so that there is more pull or draught in the chimney to prevent it smoking whenever the door is opened.
He said he had been thinking about it, but there was a problem with using 120mm steel flue pipe - condensation. As a new chimney will be part of the forthcoming building work, he felt it would be better to continue with the current arrangement, short term, then construct a proper chimney, with flue cleaning access and connect the fire to it.
I could not fault the logic and I was not relishing having the new dining room ceiling opened for the pipe route to be changed, with all the attendant redecoration work afterwards.
The wood stove sits in the corner of the dining room, where the previous owner also had a solid fuel stove. It uses the same horizontal wall exit as their stove did.
That was my first mistake. I made the presumption that if there had been a stove there for more than half a century, then it must be OK.
After my conversation with Cvjetko, I did some research on line into how to stop fires smoking. What I found in several places was that you should never, ever have a horizontal flue. I have one which is a metre long!
Chimneys should be lined to prevent condensation (not just a steel tube) and should extend above the height of close roofs, to prevent downdraughts.
So as my flue has four 90 degree bends, when you count the two at the cowl on the top of the flue pipe, which even after having been raised once, is below the level of the ridge tiles, it really couldn't be much more wrong.
So having become an instant expert in flue construction, I set about trying to work with what I have - two 90º bends and a through-the-wall horizontal pipe, and turning it into a better functioning temporary solution for this winter.
One gem of information I discovered was that if you have a 3 metre, or 10 foot flue, and you add a two foot extension, the increase in height will improve the draught by 20%. Also, a rotating cowl, powered by wind at the chimney top, will also pull air through the flue and will increase the draught. In fact there is a warning that it might cause the fuel to burn faster or hotter.
A trip to the hardware store in Stari Grad let me obtain a one metre length of pipe and a rotating cowl.
But before making any alterations, I put a meter onto the flue in the dining room. The result was zero, 0, nul, siff - draught in the chimney. That could just be a reason for the fire smoking. Not really believing the meter, I lit a small piece of paper. It smoked, the smoke rose inside the flue pipe, then came back into the room. The meter was correct, there was no pull or draught present.
Dismantling the pipe at the external 90º bend, I found one possible reason. It was more than ⅓ full of a very light, shiney black residue.
It wasn't soot as you can hold it and not get dirty fingers, but it is the result of the combustion of wood. Not only was it in the horizontal section, but it was also backed up the vertical pipe as well.
I realised that I needed to construct a device to scrape out the pipe this winter, as I am sure it will fill again. Drawing a pattern onto a piece of aluminium sheet, I cut a half circle using tin snips, then drilled the top to take a metre length of threaded bar.
The result is a custom fit rake to remove any residue which collects at the 90º degree bend at the bottom of the flue.
I suspect it is the condensation issue that is causing the black deposit.
The cold pipe is causing the results of combustion to condense on the inside of the pipe, but unlike soot which sticks, this falls to the bottom, accumulating in a heap at the bend, eventually reducing the gap and hence the draught.
With the stack pipe removed, I attached the additional one metre length, together with some home made brackets for guy wires, to hold it steady in a winter Bura. Then the rotating cowl was attached to the top.
With the help of my neighbour Steve, to steady the now three and-a-bite metre long stack, I reattached it to the wall pipe. Tightened the the support brackets, attached the guy wires and moved inside.
I have also added an air radiator immediately above the fire, so that I can extract the maximum amount of heat for the room from the fire. The meant I had to cut some pipe to fit. I also took the opportunity to paint everything to match the walls.
Just to test the new flue, I put a piece of paper over the pipe end in the room. It was almost sucked up the chimney. So with a hole in the centre, I put the meter over the hole and immediately the air vanes started spinning. It registered 3.7 to 4.9 metres per second. A check outside confirmed the new cowl was rotating.
The wind speed I was recording was only 3.2 metres per second, so it seems that the on-line information is right, that the cowl does indeed increase the draught, coupled of course with the longer pipe and the fact that it is now almost a metre above the ridge tiles.
This is not scientific, as I did not re-measure the flue after cleaning but before dismantling and the readings were taken over two days with different outside conditions. However the change in readings between zero and 4,9 should mean that my modifications have improved the draught.
I have been waiting for the plumber to return to connect up the new heated towel rail in the bathroom.
But after six months I have given up. On Friday I went to the only plumbers merchant on the island and bought a replacement Butane cylinder for my blow torch, and on Friday afternoon, I made the connections myself.
Using ready soldered Yorkshire fittings - items I had sent over from the UK, because I suspected I would have to do it myself - and working slowly and steadily, I made the connections, then filled the header tank. Going back in to check, water was oozing from one end of the rail. I swiftly placed a bucket under neath to catch the stream, then realised that I had not tightened a compression joint because after soldering, it had been to hot.
A couple of minutes later, the water had stopped. My immediate thoughts that my inexperience of soldering water tight joints was the cause had been proved wrong. It was just a simple error of failing to tighten a joint. With everything connected, I can now light the wood stove and test it, but that job I think I will leave until next week.
With the fire fixed, I will need to cut some firewood and I spent a day on dismantling, servicing and adding some replacement spares to my Stihl chainsaw.
It is at least 25 years old because it has the suppliers name, Campbells of Malton, on a label with their 0653 number, before BT added a "1" after the leading zero in 1992 and I think this is the first time it has had a proper service.
Another day has been spent this week on the old Land Rover. Some lighting issues - the front lamps not working - needed to be fixed. I knew that it was not going to be easy, because that venerable UK company 'Bodgeit, Dodgeit & Scarper' or their Balkan subsidiary seemed to have been at work.
Checking wiring at the headlamps, I found a white cable, which on opening had blue, brown and green/yellow cables inside - they had used a length of 220 volt mains flex to connect the headlamps!
Behind the instrument panel was not a pretty sight.
It took time and a digital multi meter to identify the wires and the various faults.
But after a days effort, the lights all work now, however the solution will be to buy a replacement wiring harness and do a complete rewire.
After the rain, which left puddles standing in various places, I saw several pairs of dragonflies, in their mating embrace, laying eggs.
Sadly as the puddles dry up, the chance of the eggs hatching is between nil and a minus quantity I think.
Although various dragon and damsel flies are evident throughout the year, here in Dol, where these aquatic breeders are successfully laying is a mystery.
The only permanent water is on the Stari Grad plain, some 4 kilometers away. Some species, according to my books, like clear running water, of which there is none on the island. But breeding they are, and judging by the numbers, they are quite successful.
I would like a small water feature in the big Top Orchard, but have not planned it in yet because I don't want a stagnant pool where Tiger mosquitoes will breed, and I don't want to attract snakes from the forest. The latter point was annulled when I spoke to the local snake expert in the summer and he said water would not attract the poisonous horned viper which people here fear, the Poskok. He also said if it attracted any snakes, like the harmless grass snake, he would come and collect them if I called him.
It would be nice to have a water feature, to attract amphibians and aquatic insects, so I just need to solve the mosquito larvae problem. With Herons around - I have seen one in the orchard - fish are probably not the solution, but in planning the plantings for next year, I think I will consider the idea further.
With the advent of cooler weather, the Tiger mosquitoes have disappeared, so another job this week has been the removal of the various insect screens over doors and windows and safely placing them in the store for next season.
Saturday has been wet and stormy. With an intensifying low pressure system sitting just 100 kilometers to the west of Hvar, out in the Adriatic, we have had strong easterly winds all day.
I'm pleased to say the new flue pipe has barely moved a millimeter. But there have been some very angry looking skies and there will be more rain tonight, before a fine and sunny day on Sunday, tomorrow.
We are in for another very wet week next week, so I am thinking about lots of inside jobs!