Coalpail.com Forum

This will get you started, it is not exactly accurate. there's a few extra PRV's that are unneeded and I'd have a check valve where the water enters the first tank. You don't need two tanks but with two tanks if you are using enough hot water you are always heating water , you have a lot of hot water etc.

Help on Plumbing for Thermosiphon

McGiever wrote:The circ. pump needs to be brass or stainless...never cast iron in a open loop circuit, such as this.
New oxygen is continualy being added with the new water...and oxygen = corrosion to iron/steel.

Just so I completely understand. If I put the storage tank in the basement it will not thermosyphon. However, if I add in a circulation pump I should be ok and the system will heat domestic hot water for me and I can keep the heat tank in the basement.

Is this assumption correct?

Yes. That is correct. Although if you loose power, the water in the stove will boil and create a pocket of steam since it will not be able to circulate on its own. I'm guessing it could be a problem when power is restored and cold water rushes back into the super heated jacket. This is my concern, maybe someone with more experience could verify.

I don´t want to appear over-cautious and clearly don´t mean to offend anyone who made the effort to make suggestions... but you better make sure the setup is 100% correct and not done by rule of thumb (again: I am in no way alluding to any of the statements above!). I´ve heard all sorts of stories about exploding backboilers on kitchen ranges from my English relatives -mainly my grandparent´s generation... From what I´ve heard we´re not talking about a little whiff of steam and an inconvenient puddle of water on the kitchen floor but a propper explosion with metal pieces and glowing embers flying in all directions
that picture´s taken from a DIY-blog (New Zealand or Australia if I remember correctly)

I agree wholeheartily with Firebug. If it cannot be done using modern safety norms,don't bother picking up the tools.I have seen what an improper water heater installation can do as it leaves the house via the roof and that image stays with you . Mike

I would be concerned about a power outage with no circulation resulting in an over heated water jacket then cold water rushing in that might crack it once power restored.

Edit: see next post below.....

In my previous life I was a boiler inspector for 27 years and saw lots and lots of damage caused by "That thing that would never happen."

If it is feasible it will happen.

DO NOT attempt this based on the supposition that you will always have electricity to run the pump. If you get a bump and the pump stops, you loose all circulation in that loop and the water WILL boil. You WILL develop a steam pocket and the metal WILL start to heat up to unbelievable numbers. At that point the probability turns into a certainty of having a BLEVE if circulation is restored and the cold water hits the overheated metal or it continues to heat until metal failure occurs.

The resulting BLEVE or Boiling Liquid Expanding Vapor Explosion will be more devastating than what you could imagine.

I suggest you go to a search engine and type in water heater explosion images and peruse them. Look at what a little old water heater can do when it's unleashed by improper installation or improper maintenance. Granted that those are mostly the water heaters that a lot of us have sitting in the basement. They replaced the ones in a stove and the engineering and safety devices that goes into them are some of the reasons why an exploding water heater is no longer a staple of the daily news.

Am I trying to shock you and play on your fears? YOU BET I AM and I hope everyone listens. Over my 27 years as a boiler inspector I have seen too many times the results of when people disregarded the laws of physics, thermodynamics, and the most basic installation and maintenance principles.

Follow the basic rules and they will keep you and your family alive. Install the heat source lower than tank that will be receiving the cool water from the tank. Pipe the hot water to a collection point higher than the heat source. Make sure that the heat source has an adequate safety relief valve installed and the receiving tank has one also properly rated at pressure and temperature to protect the tank. Make sure that there are no valves in the piping between the safety relief valve and the vessel it is protecting.

Rev. Larry

Yes sir! No argument there!

II appreciate all the advice. Do you all believe if I remove the water jacket that the stove could be operated safely without a jacket. Just a consideration I am contemplating.ll

Stevie wrote:II appreciate all the advice. Do you all believe if I remove the water jacket that the stove could be operated safely without a jacket. Just a consideration I am contemplating.ll

I don't know about removal of the water jacket... But you might reconsider removing it. Preheating your DHW with coal will save you a good chunk of money. Coal consumption is nearly negligible in a system like this BUT your gas bill will fall a respectable amount.

No way you can get a temper tank on the same level as the stove??

There are a couple right ways to do this and about 50 wrong ways. I went to a used book store and found a book printed around 1900 that had all the data and diagrams of how to do it right. You will boil the contents of the tank and must vent it outside but there are just a million ways to screw up. A fellow lost a foot back in the 70's because he took a shortcut. Find and old book on the subject and follow instructions.
I have the original waterfronts for some stove made in this area. Most are loaded with scale and will really never be save again. I scrap them from time to time. I do have a few that are bronze. They are like new.

ok thanks for all the good advice. Now can anyone suggest where to get a good used hot water storage tank to connect the stove to for storing the water?

I recently watched a YouTube video on hooking up a coal stove as I suggest. They had hot water tank on the second floor above the coal stove. I could place on tank directly above and to the right of the stove in the upstairs bathroom. I would use pecs to run the lines through the wall up to the tank. Would these be an alternative to having the tank on the same level as the stove? And would this eliminate the need for a circulation pump?

https://www.youtube.com/watch?v=HMf3wOb6NPw

Yes, up is good...down is bad. No pump for up.

Pex...maybe scarey...200*F Max. and as pressure goes higher, temp. rating goes lower. (it is plastic)

Maybe spring for soft copper instead of pex.

Yes that should work just fine with no pump. I'd choose to use copper instead of pex though. I used my old propane fired hot water tank for a temper tank. I just pulled the burner out of it and stuffed the burner area and hollow center with insulation. Works great