Do they still make these for Stove pipes?

City Bound · #1 02/27/12, 07:16 PM

FarmboyBill · #2 02/27/12, 07:25 PM

Id say no, but Lehmans would know.

billooo2 · #3 02/27/12, 07:30 PM

It looks like that was home-made .......not purchased.

I don't know if Mother Earth News may have some of those old artlcles (like 'Blazing Showers') on-line or not.

One of my neighbors in Maine had something similar. Pete just mounted some copper pipe on the side of his wood stove. And when that pressure relief valve would pop-off....it would certainly 'get your attention!!!'

watcher · #4 02/27/12, 07:34 PM

I'd say definitely not like that, there's no pressure relief valve. I'd not want to have anything like that on my stove w/o a relief valve.

And to be honest with you it looks home made.

City Bound · #5 02/27/12, 07:38 PM

the guy said he got it at an estate sale, maybe it was an old model. it needs to be attached to a tank. Couldnt the tank have the pressure valve?

Bearfootfarm · #6 02/27/12, 09:14 PM

The tank could have a valve, or it could be an unpressurized open tank

Harry Chickpea · #7 02/27/12, 09:30 PM

That setup, especially with a simple box stove, is a chimney fire waiting to happen. I've been around that block a few times back in the 1970s. Here is the scoop:

Stack temps need to be above the condensing temperature of the water in the waste gasses, just as a starting point. Otherwise, the gasses and creosote quickly coat the cold surface, you get smoke in the room because the fire doesn't draw properly, and so on. What happens when the inside surface gets coated with soot? The coating acts as an insulation, quickly keeping the device from extracting heat the way you think it might. Eventually, enough stuff condenses out that a spark can ignite it during a hot fire. Viola, chimney fire. The concept is an idea that is based on the thoughts of people who used coal, or had extremely clean burning fuels. I would not have one around.

You can extract extra heat safely around the firebox (if you keep the firebox temps hot enough for proper combustion). If you want to scavenge heat get a wood burning water heater (which I also don't trust, but they are safer) or scavenge outside of the living space, like in an outdoor boiler.

mrs whodunit · #8 02/27/12, 09:53 PM

There is somebody that makes stainless steel one in Austria I think it is. Trying to find the link................. its driving me nuts as I cant find it. Wasnt even smart enough to bookmark it LOL

Edited to add its Australia Axemans Fire-Flue water Systems

solidwoods · #9 02/28/12, 07:13 AM

If he plumbs it to his domestic water heater it has a pressure relief valve.
I'd use copper from the hot water out pipe to the domestic HWH.
I don't like the design he shows on his computer. I'd hook up the stove water heater directly to the HWH tank and convection would circulate the hot water, or use an electric pump to send the stove hot water to the tank.
The vid says "it is the rising column of hot water that forces the hot water through the system". But the pic shows that is incorrect. The rising column of hot water cant go anywhere till a fixtures valve is open and BOY OH BOY are you going to get some scalding water for a few feet.

I've considered building one of those to plumb to my outdoor woodfired water heater plumbing. That system has continuous circulating water in the feed/rtn lines.
I'd go with a little different exchanger design.

Yep Harry that's definitely a chimney fire looking for a place to happen. Also the horizontal pipe adds to the effect because if creosote does crack off inside the pipe, gravity can't send it back to the stove. The horizontal pipe is a common mistake people make.
jim

City Bound · #10 02/28/12, 07:31 AM

Harry, do you think a coil inside the stove is the safest way to attach a hot water tank to a wood stove?

ET1 SS · #11 02/28/12, 09:44 AM

I have not seen anyone making that device.

We use a Vogelzang Double-barrel woodstove, We have 50' of copper-tubing coiled inside the upper barrel that heats our water. You seriously need to have a pressure-relief valve on it. Otherwise a water-heater can make a huge explosion.

solidwoods · #12 02/28/12, 10:10 AM

If you have a pipe picking up heat the water in the pipe must be circulated and regulated so the total water quantity doesn't get over scalding temp !
If its not circulated the water will boil and make steam pressure.
jim

Ken in Maine · #13 02/28/12, 10:17 AM

Get a camera on that so you can send the explosion to America's Funniest Videos... although this would not be a joke. Can you say " dangerous"... Not only can it explode but if not properly installed at the water heater you've got a scald bomb waiting to happen. Imagine just how hot that water can get....

Harry Chickpea · #14 02/28/12, 10:41 AM

Quote:

Originally Posted by City Bound

Harry, do you think a coil inside the stove is the safest way to attach a hot water tank to a wood stove?

I've thought about the whole concept from time to time. IF I was to attempt something along those lines, I would zigzag a copper line across the bottom of the firebox, then up the interior wall of the stove that was closest to the house wall, then chink between it with firebrick and fireplace cement and use an open tank above that - possibly even in an attic. If I needed pressurized hot water, I'd run another copper coil inside the top of the tank to act as heat exchanger.

Why like this? There is heat from most woodburners that "cooks" walls and floors. Keeping those areas cooler (but not cold) serves a double purpose. An open system is inherently safer. The two worst case scenarios would be a steam burst into the open tank, which would make a noise and other than that do no damage, and a burst pipe in the firebrick would create a leak that would put out the fire and get some water on the floor. I could live with that.

The use of the firebrick both mediates the temperatures and acts as a physical barrier to keep the pipe from getting hit by logs tossed in.

To properly do a boiler, you need to design around the idea of a boiler. To scavenge heat, the way I described is about the simplest and safest I've been able to think of.

City Bound · #15 02/28/12, 10:54 AM

hmmm a lot to think about about.

tinknal · #16 02/28/12, 04:46 PM

Harry, those old box stoves are horribly inefficient. Smoke needs to cool to around 240 degrees F before creosote condenses out. I doubt that that devise would cool the smoke down that much.

Harry Chickpea · #17 02/28/12, 07:23 PM

Quote:

Originally Posted by tinknal

Harry, those old box stoves are horribly inefficient. Smoke needs to cool to around 240 degrees F before creosote condenses out. I doubt that that devise would cool the smoke down that much.

With a proper hot fire, you are absolutely correct. There is a big however though... Ramp up and ramp down, plus improper use of draft controls, plus typical messing up with damp wood, incomplete combustion and so on makes it much more likely that there will be significant periods when creosote condenses. Remember that water temp is going to be under 160 degrees at all times under "normal" operation, and the transfer zone temp will be about 200 at best.

The method I described is far superior.

tinknal · #18 02/28/12, 08:08 PM

Quote:

Originally Posted by Harry Chickpea

With a proper hot fire, you are absolutely correct. There is a big however though... Ramp up and ramp down, plus improper use of draft controls, plus typical messing up with damp wood, incomplete combustion and so on makes it much more likely that there will be significant periods when creosote condenses. Remember that water temp is going to be under 160 degrees at all times under "normal" operation, and the transfer zone temp will be about 200 at best.

The method I described is far superior.

True, but for the very facts that you stated, there will never be a consistent enough temperature for condensation to occur uniformly. I used to be a chimney sweep and I ran into a lot of those old stoves. My bigger concerns with that setup would be that long horizontal section of the stovepipe. As close as that water heater is to the stove my guess is that as soon as any does accumulate it will burn off quickly. There is quite a bit of wisdom in the notion that it is better to have a small chimney fire every day rather than one big on some time in the future.

Harry Chickpea · #19 02/28/12, 10:16 PM

I remember a couple three grange and church halls with those long horizontal pipes... BUT the small stoves they used were obviously designed for coal, and if they did use wood in those huge halls, they used what most people would call kindling and cranked to the max to heat the hall for the meeting, then let it completely die out. TMEN had all sorts of disputes on those long reaches being safe or not. Never bothered to get involved.

haypoint · #20 02/29/12, 06:36 AM

I had a water heater in my wood cook stove. The key here is to set up the water tank so that the water will NATURALLY circulate into and out of that tank. It can’t get scalding hot, because is circulates before it can get that hot.
But you MUST have it plumbed to a tank and arranged so that the hot water goes up, into the top of the tank and the lower pipe is close to level to the bottom of the tank and the bottom of your coil heater.
As the water in the coils warms, it rises and flows into the tank. That draws cooler water in from the bottom of the tank. Water will continue to circulate until the whole tank is hot water. I’ve never been able to get the water anywhere near 200F. Yes, it should have a pressure relief valve.
It will cool the stove pipe a little. But in that setup, it is right out of the stove and isn’t going to cool it much. As a side note, that stove pipe damper he has right on the stove, should be moved to just above the stovepipe heater coil.
He also has a long running stove pipe. That helps heat more of his house, but it also gives you a few places for creosote to leak on stuff. That long run could cool the smoke enough to crate excess creosote. Then after that long run, he has a heat saver. I had one and it plugged up so fast with creosote, I had to remove it. Water heater, long horizontal stove pipe and a heat saver, in combination spells chimney fire, to me