Wood boiler

[Saidrich]

Here are a few pics of a wood boiler system Which as set me free from the gas company.



You will notice a red box mounted on the wall. This is a thermalcouple powered temperature control which starts my pump when the flue temperature rises.

This design has 60 feet of coils (40'- 1/2" on the bottom and 20'- 3/4" on the top. This allowed for an opening in the middle of the boiler for loading wood.

The system has full battery backup power with automatic switching from grid.I also tried my hand as lathe work and machined the headers



I also have a stainless heat exchanger that heats my domestic hot water. There are fan coils in the bedrooms. The entire system draws about 150watts

[harrie]

It is a good feeling when a guy can make up something that makes you not only self sufficant, but to save money at the same time!!.Those copper coils, work very well. do you have a expancion tank, and pressure releif valve in the system? I have put coils in a 30 gallon water tank, that is for potable water. My outdoor wood stove, sends 180 degree water thru the tank for my heating system, and heats up the coils for instant hot water at the facets. works well. Good job, Harrie

[Saidrich]

The pipe in the boiler is scd.80 steel pipe but I use copper tubing for all my zones better for taking the heat. Yes I have feed water and pressure relief valves along with expansion tank. Also put a small hot water tank up by the ceiling for storage and to give a little convection flow.

 Here is a picture of the battery backup which didnt upload for some reason.

[Volvo farmer]

That's pretty neat. Do you have any safety concerns with this thing? The way I've always understood boilers, if the heat can't be shut off and the pump fails, there's a decent chance of making steam in those pipes which could turn schedule 80 pipe into a bunch of flying shrapnel.

[Saidrich]

"Flashing" the boiler was taken into consideration. There is a pressure relief valve that lets the pressure of at 30psi or 230degrees The hot water tank mounted by the ceiling moves the water through convection (not very fast though) and the battery backup runs my water pump in case of a power failure. Just remember, you WILL flash your boiler no matter what fuels it. Always have a pressure relief and expansion tank. When this boiler flashed in the past it was because the pump failed. Thus the battery backup for the pump.

[WXYZCIENCE]

Pressure relief is required on all boilers. The water tube boiler of this design has very little water in it. In the case of a flash the water is expelled through the relief valve and the steel tubes can operate without water. The tubes are pressure tested to 300 psi. The system runs at 7-10 psi, this removes air from the water which is corrosive to steel, a drawback to open air systems. Joe

[Ampman354]

really neat system and congrats on getting away from the Gas Co.

[maker of toys]

Nicely done-  I like the way you've recycled some of the gas company's stuff too. <G>

one minor nitpick-  I think you will be unhappy with the effects of the galvanized fittings in your headers.  (yeah, yeah, I can see that you have brass dialectric sections between the copper and the iron, etc, etc. . . ) my experience is that steel and copper get along fine, unless there's zinc anwhere in the system. . .  then things seem to corrode, and often where you don't expect them to.  as an example:

We build my dad's place with all copper pipe except for the laundry shutoff valves, which were galvanized with brass dialectric isolation.  it took me a lot of head scratching to figure out why 2 washing machines rusted to nothing in 5 years each  (I'm talking 'push your hand through the case' rusty), while the drier right next to them had no rust at all.  we finally changed out the galv. shutoffs (which were fine) for brass ones and eliminated the 'stainless'-braid feed lines (which were corroding(!)); the current washer is 15 years old and going strong.  Maybe it's just the wierd water we have here? In any event, I recommend changing the zinc-plated fittings for black iron at your earliest convienience.

Just a thought.  I'd hate to see that nifty little boiler die a premature death.

-Dan

[Saidrich]

Thanks for the heads up. I really like your last sentence, I think I might take your advice. My first header was all black iron what a mess. I have seen 1/2" black iron fittings you couldn't fit a pin into when they are removed. I would like to change all the fittings to brass, there are only three.

[warznorth]

There is a site wich has user reviews on wood boilers, I used to own a central boiler outdoor wood stove, I was able to put in my 2 cents on the smokey monster living in my back yard.

http://www.woodboilerheat.com/

I moved away from that smokey monster and the next house I purchased needed cheap heat so I looked at outdoor wood boilers again, dont ask me why, I found a local guy who was building them, his was half the price of one of those commercial stoves so I decided to try it, best $4000 I ever spent, it didnt smoke had a 12 hour burn and performed better than the name brand one I had paid $9000 for, just goes to show what old fasioned homebuilt craftsmanship is worth

[Saidrich]

this unit cleanly burns a small fire and gains its efficiency by taking the heat off the fire via the steel tubes. I have walked up to my house in -30 and was unable to see smoke out the chimney. (I'm not kidding)