Hot water from your stove

[electrathon]

I am starting a new thread. I will try to explain what I did to install the hot water system in my stove. I will start by saying, I have a good knowledge of construction, plumbing, electrical, contracting. I am not a beginner when it comes to making things. If you are not comfortable with what you are thinking of doing, please step back and stop or regroup. Wood stoves can be dangerous, so can water heaters.

I have heated my home with a wood stove since I moved in in 1986. I always wanted to integrate the water heat into it and finally did in 2013. In the winter I run my stove constantly, it is able to heat most of the hot water used in my home.

The stove is a Hearthstone Heritage. It is installed into the opening of the original fireplace. The home was built in 1932. I debated what and how to install the coil for a long time. I was originally going to drill into the soapstone to run the coil in, but felt I was committing some sort of soapstone stove sin. I settled on machining a new block off plate for the top of the stove that I drilled to run the tubing through. The coil is 3/4" stainless tubing. It goes into the top, loops in a rectangle above the internal heat deflector and exits through the top plate. I had the tubing bent by a friend who works at a local tubing shop. It has been a while but memory says the tubing was about .080" thick, this was not thin walled tubing. The interesting side to the coil bending part of the story was the guy is Russian. When he was a young boy his father installed water coils in wood stoves to make extra money. In the area they lived many people did not have water heaters, unless they added coils into their wood stoves.

I knew that the piping would be very visible. I opted to go for a Steampunk look, adding extra gauges and dials. There is a check valve 6" away from the entry point to the stove. Directly at the exit point there is a thermostat. It is fun to watch it as the water cycles. Next, 6" away is the thermo-switch to the solar controller. The system works almost identically to a roof solar panel. If you are familiar with them just envision the part in the stove as the part on the roof of a solar install. I installed the thermosensor a little away from the stove to help lengthen the runtime of the pump cycle. Next is a water per assure gauge. Not necessary, but looks cool. It usually is at about 64lbs, I am on a city water system, nog a well. There is an air blend valve by the pressure gauge but it was not really necerry, water velocity purges the air well.

I will jump to another post to describe the rest of the tank side of the system. I am afraid of loosing what I have already typed.

 

[begreen]

Previous thread on same topic:
https://www.hearth.com/talk/threads/wood-stove-water-heat.146326/

 

[jharkin]

Do you have safety valves integrated to protect you from a steam explosion if power goes out or the pump fails and you boil the water in the coil?

 

[Wisneaky]

Do you have safety valves integrated to protect you from a steam explosion if power goes out or the pump fails and you boil the water in the coil?

And here we go again. Please read the previous thread.

 

[jharkin]

And here we go again. Please read the previous thread.

Excuse me????
It was a photo without any detail. I did not know there was a previous thread...

All I know is that my insurance would cancel me if they found something uncertified like that in my house, so I asked a valid question about its safety features.

 

[begreen]

Link to original thread now posted. That should answer most questions on safety features and design considerations.

 

[Highbeam]

Excuse me????
It was a photo without any detail. I did not know there was a previous thread...

All I know is that my insurance would cancel me if they found something uncertified like that in my house, so I asked a valid question about its safety features.

You're right, it's like a guy using single wall stove pipe through the ceiling, attic, and roof up to a cap. Sure, he hasn't burnt his house down yet since he has smoke detectors but all forum members have a duty to call BS on the safety.

 

[jharkin]

Ok now I see the thread link... looks like BG was typing at the same time as me and his post hit first. I see you argued it all out, im done.

 

[Wisneaky]

If it was up to me I wouldn't even let this thread start back up. It's a unique setup. Is it dangerous? Yes it could be.

 

[electrathon]

For water storage I have a 50 gallon electric water heater. There is no electricity going to it, just was a low cost storage tank. The water is drawn out of the bottom of the tank, at the drain, and is pumped to the stove. My tank is in the basement about 35 feet of pipe away from the stove. When the SolarHot water controller sees a 15 degree difference in the tank and the stove, the pump turns on. The tank sensor is located at the water drain point. The pump is a Taco 007 stainless pump, located in the return line, at the tank. The slug of warm water enters the tank at the water "in" point, so that it runs low in the tank, mixes with the water and heated water will rise up to the top of the tank. When the temp equalizes, the pump then turns off, usually less than a minute.

When I first installed the system I was expecting water overheat. I was actually hoping for it. I was going to use a tempering valve to redirect hot water to a baseboard heater in the basement. Sadly there was not enough excess heat to do that. There is an expansion tank in the hot water piping to control any expansion as the water is heating, there is a pressure pop off valve if the water gets too hot. I never get any place near that point. I have ran the system as a test for over an hour without the water temp even coming close to boiling. I for a long time did not have, but now have put a UPS on the pump (my bottom was sore from getting chewed on here about not having this). The meter on the ups says it will run for 187 minutes with the load the pump has, and that is run time, so it will run for hours of clock time. I have generator I will plug it into if there is an extended outage, which is rare around here.

When the water leaves the preheat tank it goes to a Renii insta hot heater. If the water is fully heater I just turn the water heater off. If it is only partially heated the water heater just works less heating the water.

I want to clarify, this is how I did this. I am not telling anyone what to do. The system is not that different, except for the pump, to the millions of systems all around the world. We used to do this in America in the past too. My Grandparents lived in a cabin that had no hot water unless you built a fire in the cook stove. Energy was so cheap we just started using propane, natural gas or electricity instead. This is a step back to energy independence. I like that feeling. I cut wood, I heat my house. I also heat the water as I heat the house.

 

[electrathon]

Yes, there are safety features. Wood stoves can be very dangerous, I am aware. Water heaters can be dangerous, I am aware of that too. Mix the two and you do need to use caution. This system is basically a solar water system, but the coil is in the stove, not the roof. I get no where near the heat that is generated in a solar system, not even close. If there was an over heat the pop off valve is capable of opening if/when that did happen.

If you look at the pictures of stove explosions you can find on the Internet, the blow up issue is generally caused because someone closed both the inlet and outlet valves to the stove, trapping the water inside the stove. Why this was done, I don't know, but as the saying goes, you can't fix stupid.

I think a lot of the fear is from lack of understanding. I do realize that wood stoves harm and kill people. We still use them. I am cautious with mine, I maintain it. I know water heaters also kill people, yet every person here has one of them in their house. Many do not inspect the pop off valve, and that can lead to a very dangerous explosion. Solar systems are common all over Americe, they can boil water too, which can cause harm. Our government encourages us to add them to our houses.

I did a lot of research before building this system. There was not a lot of information easy to find. Solar information was the most plentiful. I have background and knowledge in construction. I did the stove install myself, dropping the liner down the chimney was not a fun task, my house/brick chimney is tall. I work with/am friends with two different plumbing inspectors (I work for a small town). The one told me he used to work in a more rural area and used to see these systems often. He had no problem with them. He was the guy that I thought would cringe a little when I told him about it.