Thursday, September 19, 2019

Answer to Request for a Diagram of the Cookstove Hot Water System

Yesterday, I received a request for a diagram of our hot water system from a reader who is installing a similar system.  I apologize for my extremely poor artistic ability, but here it is.  I put together two views since the plumbing is divided up that way.  Below the diagrams, you will see a key to the red letters in case the words on the diagrams are too difficult to read. The scan is long, though, so you'll have to scroll down through quite a bit of white space in order to see the key.


A. Temperature Pressure Relief (TPR) Valves
B. Hot Water Line which exits the top of the waterfront on the cookstove, carrying hot water into the top portion of the boiler.
C. Check Valve which allows cool water from the bottom of the boiler to only flow toward the stove, not vice versa.
D. Cool Water Line through which cool water from the bottom of the boiler flows into the bottom of the waterfront on the cookstove.
E. (left side diagram) All TPR valves are connected to a common drain pipe which empties toward the floor drain in the basement.

E. (right side diagram, sorry!) Hot Water Pipe exiting the top of the boiler.
F. Tempering Valve-Hot water from the top pipe enters this valve and is mixed with cold water from the supply line in order to have control over the temperature of the water in the household system.
G. Cold water enters the boiler at the mid point opening.
H. Hot Water Line to household system.
I. Cold Water Supply Line

Here are some actual pictures of the system:





I hope this answer's the reader's question.  If not, let me know in the comments what more I could help with.  The system certainly works well!

9 comments:

  1. Thank you so much! I'm planning a total plumbing renovation/cook stove install. Pretty much all of the current system will need to go. How hot is the water, approximately, coming out of your cook stove? My stove is a yet to be installed Tim Sistem North with DHW coil.

    I take it the last photo with the valve with black handle is the tempering valve. Does your Vaughn range boiler have a port on the bottom? I was considering using this to feed cold water into the DHW coil and then using one of my top ports for water going back in. However, your system looks like a much better setup. Is all of your piping 1? I'm pretty sure the DHW coil on my stove is a 1" pipe.

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  2. Well, it looks like I was mistaken and after taking an actual measurement it seems everything is 3/4" on the range boiler and cooker. This is much easier. Do you know of any 200f temperature and pressure relief valves? Most of what I'm finding is meant for a bit higher and I'd like to use pex tubing for plumbing.

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    1. I don't know what the temperature of the water coming out of the stove and flowing into the boiler is. I have measured our tap water (post tempering valve) at 170ºF, but we suspicion that our tempering valve is temperamental because the plumber bumped it hard enough to break the black handle off of it during the install.

      You are correct that the black valve is the tempering valve. The handle is supposed to have a little metal plate on it, but alas, see above paragraph.

      Our boiler does have a port on the bottom. However, it sits on a slab of black marble, and the plumber could find no fittings that would make the right angle in as short a space as there is between the bottom of the boiler and the black marble slab. Therefore, the port just remains plugged.

      Sorry, but I don't know where one might find TPR valves for different temperatures. However, I wouldn't recommend pex tubing between the stove and the boiler, and I also wouldn't advise relying on the TPR valves to protect the rest of the house system from water that is too hot. For that, you really need to rely on your tempering valve.

      The water traveling between the stove and the boiler is VERY hot, and you don't want your TPR valves releasing on a regular basis.

      Before installing our system, we looked at a set up in an Amish home. They had a 40-gallon tank hooked to their cookstove, but they had to manually lift buckets of water into the open top of the tank and would just draw water through a valve on the bottom of the tank for use. Obviously, they didn't use as much hot water as they would have if it were on tap, and they told us that in the winter when their stove was continuously fired, the water in their tank wanted to boil.

      Hope that all helps! When you get everything installed, I hope you'll be willing to send pics and let me do a Reader's Cookstove Post about your installation.

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    2. I will certainly come back when I'm done. Your input has been really great since most folks don't do this anymore.

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  3. This is bookmarked. Thank you so much for this information.

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  4. How long did it take for your tank to come up to temperature? I just got my system operational!

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    1. Yeah!
      I'm not sure how to answer your question. With a good fire, we can have enough hot water in the tank for a shower in about a half an hour. However, if you run your hand down the outside of the boiler, you'll notice quite a fluctuation in temperature with the hottest part being at the top, of course. The whole forty gallons of water will be hot after several hours of having a fire, but of course this also depends on how much hot water is used in the mean time. Let me know how yours works out!

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    2. So far I've gotten the water coming out of the RB quite hot, above 120 df. I think it would be higher, but my wife likes to take baths and she's been feeling quite ill lately. I think your water jacket is more robust than the simple coil in my cookstove. Perhaps when we put walls up and finish remodeling the kitchen the cooker will get a water coil with a loop or two for more surface area. I've been able to bring the tank above 100 df from 65 df after my wife's morning baths after a few hours of burning in the stove. Another part of this is my apprehension of burning the stove really hot. I don't think I've even gotten the oven above 350 df. This evening I plan on cooking some chicken thighs at 375 df or higher, so we will see how hot the tank gets.

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    3. Sounds like you're getting there. You are probably right about the water jacket heating better than a simple coil. We've got probably two square feet of surface area making direct contact with the fire, so it makes sense that we'd have greater water heating capacity.

      Hope your wife is feeling better soon. At least the hot water for the baths isn't costing you anything extra!

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