Modifying an insertable wood stove to add double combustion and fans

In this post, which had long been "waiting" for various reasons (my apologies to Alberto, intone the mea-culpa), an animated friend of sustainability we discuss how modified 2014 a stove without too much effort to optimize its performance , having fun how nice in the process.

Alberto tells us who dared to take pictures of it and write it done because it came in handy examples and information I put in this blog.

Adding steel tubes for double combustion and fans increase the combustion efficiency to deliver oxygen where it is needed, and also preheated, and fans are needed to optimize the extraction of heat to the room and extend the life of the stove by reducing the temperature of the structure , which otherwise would be very stressed by extreme temperature changes to increase performance. These modifications are safe (with the only danger plaster smoke, controllable and which will be discussed in detail). 

So, without further ado, let him be himself who tell us (apologies for the quality of the photos):

Presentation and project

The first is to introduce Alberto and I am not a professional in this sector, but I like the tools and I dare all.

I needed an insertable for the house in Ávila, at 1360m above the sea, as the chimmenie fire never could heat the cold granite house. And of course I wanted to double and double combustion chamber. 

I do not remember very well the extent of the gap in his fireplace; would be about 530mm, about, quite recently, I found an insertable fire made ​​of that size. The sides of the fireplace are also granite but the problem is securing a roof beam in the middle of the house and did not make me any grace the walls shake too.

So I Have This Test was willing to custom. I was asking for tempered glass in the door to start ... phew... 'find materials that work !!.

By chance I found a home at a low price approaching the measures, and for 250 euros I found very interesting in Leroy Merlin especially since half the work had already been done.

I fixed that has markings and grooves on the overlap in the area that would stick to the wall on the inside, suggesting that it could be mounted with double chamber plate, ask for some advanced model with the camera and fans, but not I know answer ... In the end I'll take it.

Modifying the stove

I step by Rivera Street Tanners 16, stoves Martinez, and I buy fans (special aluminum high temperature), silicone cable, switches, temperature switch, plate heat insulator and good advice they gave me (highly recommended people if you want to undertake a similar project) ... 100 euros everything.

In addition, I buy the plates sheets and tubes that I need ... another 60 euros.

I'll take the people ... as it weighs jod ** I have to remove the door and all parts to manipulate home alone.

I start chopping the wall a few centimeters on each side, I use for hard granite hilti a ejectors nailers . They are great for starting small pieces of stone:

As the air outlet holes of dual chamber are marked on the overlap,   I open based drill and lime.

I take this opportunity to give a shot to the flue-plated 1.5mm

Home "upside down", will I present the fans with aluminum blades and I will be measuring the metal structure as the hostel with the plate with the controls and electrical system:

White cardboard insulation is I got in Martinez, isolating the fan from direct contact with the melt.(Red arrows), also pay sheets to channel air and only pass by fans (blue arrow).

In the plate hole to place the switches. Finally I put some thick I had lying around. I put 3 to make an invention that then did not do for lack of time, but 2 work, each for a fan. I make the plate removable to repair or remove in the future fans:

Here is the bracket with fans installed with the electrical system and in the absence of superior insulation and thermal switch that is connected to the loose threads that are at the bottom:

Once amount all, I give special putty stoves enduring high temperatures in all the cracks to avoid losing forced by anywhere shot .

I start to weld the camera, with 1 mm plate in the photo is Mount Union fans with home, and the same substance. At the top a large plate for air vent, which will subsequently sealed with caulking hole:

 Although I did before, I put it now to bring order; this drill 20mm diameter, passes through the molten soil of home, and gets into the double chamber air circulation fans, for them I will draw tubes with grid to the main chamber, which will double combustion entering part of fan air tubes in the grid:

And this is the grid. This is a hollow tube rack with 20 sides and 14 on the cross, with little holes 2.5 mm (I'm not sure or maybe 3mm) which is where the hot air will come out.

I anchor the grid in the 20mm hole made in the bottom of the home, using a shoe and screw m8, (you have to give the molten thread).

The following photos correspond to the fireplace lined with galvanized sheet metal and an insulator paste as those put behind radiators, which proved to be very useful because it took off and scorched the first power; that if .... It was lovely in the photos. (Note to David: I suggest placing high temperature insulation in place, as inconel textile enduring 1000C).

After screwing granite galvanized and seal the holes with putty sheets.

Chapon 3mm Nivelo one that will support the weight of the insert, and also leave room for cold air to pass underneath. Already it has done the hole where the power cord passes.

Then pay a shield platen that will received with cement to the wall with a pin, which is where the overlap of home support. On the top of the shield I put a metal grid inside so that the flue pipe is not seen. It will be attached with magnets

Finally I make the fireplace. It is a big problem that arises me, as the shot is not straight, but back in oblique, and also not for the hole in the base of the chimney with the hole is in the air vent, is much smaller. I have very little height space between home and vent. It forces me to entroncar, or twist the exit and as I am not very good boilermaker, and I also have no tools to do so, it strikes me make it through a square box, which was first thought to cross tubes 20mm with a fan behind and output hot on the grid ahead shield air (hence 3 switch controls), or what is the same a heat exchanger in the flue, but due to time constraints I leave it for another time. I only chimney-shaped drawer. The second picture is the position that is at home, with the top up, crossing the galvanized sheet and being free in the original hole of the chimney.

Total 410 euros materials, without light, electrodes, gas to get back and forth ....  Later in another Leroy Merlin found the same home and become insertable with its fans etc ... that if, without double combustion and a very good price 550 euros .... It made ​​me wonder if it was worth me so much grief work, I have concluded that if it was worth the hours of enjoyment doing things myself and almost self - taught , with the help that if the previously published materials in blogs and forums. Sure I will have made ​​mistakes, but next time I'll do better.

Stove operation

In the winter of 2015, after several months of use, home works great , fuelwood consumption was once continuous, every so often had to put a couple of logs to keep the fire burning, but the room was never hot. It is a little isolated stone house in Avila (harsh winters area) as I said before, with the gabled roof, with fairly high ceilings, the living room and fireplace in the middle of it; The fireplace was not even able to heat the room.

With this new system consumption has considerably decreased, a single hard trunk several hours (keeping the shot reduced air), making the very comfortable lounge (too much for my taste, that if my delighted woman) even I open the doors of the other rooms to warm them.

The double combustion household works well , looks like enters the air above and burned by the smoke, as if gas is involved, but I have to try enlarge the holes, at least the center of the grill, because I It gives the feeling that not enough hot air enters and leaves still some smoke up the chimney.

A mistake I made was to put the temperature switch in a somewhat elevated and has already ruined my position, it is locked with the closed contact so that when I connect the switches are set to immediately turn the fans without waiting for is hot molten. I'll have to unmount it to peel it off or replace it.

As for safety, something that I am also pending is the ability to revoke or change of direction in the flow of smoke into the grid double combustion, entering it into the room. In Martinez they explained to me that good and expensive insertable have a check valve to prevent this, although not usually very common operation and insertable thermodynamics itself. 

Note David : Alberto checked this possibility closing shot and in this case the fire was extinguished without plaster, I guess that's the difference of temperature and pressure, so the moment is safe, but it is recommended that there is a minimum opening calculated in the chimney flue so that in case of failure of the shot, the smoke continues to have the tendency to go until the wood runs out .

I hope these lines you like and give you ideas for your project.

Legend: GREY: The profile of the original stone.

BLACK: Original Home.

BROWN: The plate surrounding the home or double chamber.

BLUE: The double combustion grid.

MORADO: Fireplace with heat exchanger.

GREEN: Top fan heat exchanger and forced draft fans down.

Greetings and thanks to Alberto, Great job, congratulations on the success and thank you for sharing your ideas and impact on the Community! Surely more than one would fail.