Wood/ Coal Temp Difference

This is my 1st year burning coal and I wish I started years ago . I often work 12-16 hrs a day and needed that long burn times to keep the fire going between fill ups. I also heat 100 gallons of DHW with my stove ( I just hooked up this year) so that's a plus for the electric savings. I do have a slight problem and a question. When temps get low somewhere in the low 20s and lower the stove isn't keeping the house as warm as I would like . My propane kicks on when it hits about 69 and its running at nights.( we like it in mid 70s ) I turned the bimetal damper up to around 3/4 open but the heat still kicks on . When it's cranked up my hot water tanks are popping the high temp valves and dumping hot water. We are a family of 5 so there's several showers every day. This house is well insulated with 2x6 walls and insulation poured in the basement block . It's 11 yrs Old 1980 sq feet with a full unfinished basement where the stove is. There's a hood over the stove that funnels most of the heat into my return and a stat that kicks on when the temp gets high above the stove to circulate the heat through the house. When burning wood the house was a lot warmer ? I used to have condensation on my Windows and a warmer house. My question is , I thought coal burned hotter? It's around 350 on stove top now . Wood was at least that but short between fill ups. Should I unhook my DHW and crank it up more to keep the house warmer ? Or is there something I'm missing?

Actually stove top is about 425 now with bimet set at 3/4 open

Please tell us more about the domestic hot water heating system you have in place.

Lightning wrote:Please tell us more about the domestic hot water heating system you have in place.

It's 2- 50 gallon elect tanks hooked up next to the stove elevated on stands . No pump to circulate or fail. Just thermal circulation that has the coil in stove. It works great but gets to hot when the stove is cranked up. There's an air vent installed to bleed any air in system. I also put in valves to bypass the stove if needed. ( I know that's a poss danger problem ) but I'm the only person fooling with it . This hook up is in the middle of my house my drain is a 5 gallon bucket that I check whenever I'm tending the stove. Prob is it can and does over flow when the stoves hot.

Subscribed to this thread. I want to set up a system like this. I'm affraid if I put too much coil in the stove I'll end up blowing off, not enough and I wont make enough hot water. One thing I have going for me is that I have a 300 ft pex run in the basement floor where I can dump extra heat to prevent popping the relief valves

Do you know what temperature your water is getting up to when the relief valve blows?
Are you sure it's not blowing due to pressure?
Are you using an expansion tank?
Maybe you need to forget about using your stove for hot water when it gets to cold out so you can increase the temperature in your stove.
Or use a pump and hook up something to dump off extra heat when your water gets to hot.
Scalding is a serious danger.
Also if you are shutting valves isolating your coil in your stove with it full of water I highly suggest you install a drain valve to drain that coil.

Waswood wrote:

Lightning wrote:Please tell us more about the domestic hot water heating system you have in place.

It's 2- 50 gallon elect tanks hooked up next to the stove elevated on stands . No pump to circulate or fail. Just thermal circulation that has the coil in stove. It works great but gets to hot when the stove is cranked up. There's an air vent installed to bleed any air in system. I also put in valves to bypass the stove if needed. ( I know that's a poss danger problem ) but I'm the only person fooling with it . This hook up is in the middle of my house my drain is a 5 gallon bucket that I check whenever I'm tending the stove. Prob is it can and does over flow when the stoves hot.

Okay, do the electric tanks have power hooked to them? I take it the two tanks are connected in series? Shut off power to the one that the coil runs into. Use that tank as a preheater. Or is that what you are doing? Have you taken any temperature readings?

Eb426 wrote:Do you know what temperature your water is getting up to when the relief valve blows?
Are you sure it's not blowing due to pressure?
Are you using an expansion tank?
Maybe you need to forget about using your stove for hot water when it gets to cold out so you can increase the temperature in your stove.
Or use a pump and hook up something to dump off extra heat when your water gets to hot.
Scalding is a serious danger.
Also if you are shutting valves isolating your coil in your stove with it full of water I highly suggest you install a drain valve to drain that coil.

It blows when the temp gets a little over 200.( if I recall correctly its 210?) Yes I have valves to shut off stove coil and a drain to empty that section of pipe going through the stove . We are on a well and there is an expansion tank but it's a ways away from the stove. I originally had similar problems but I changed some plumbing. ( the pic was of original hook up) . It all stopped except when the stove is turned up. If we all 5 get showers every day it may be ok . Although the kids skip days sometimes.

Here's the current hookup. Please don't make fun of my plumbing , it was my 1st time soldering copper . I was told it looks like a moonshine still. as you can see the temp about 190 now and that is with 1 shower just taken.

It isn't blowing on temperature. The water in the coil isn't moving and he is running the stove hard and that is trying to make steam. The pressure builds and poof goes the valve.

coaledsweat wrote:It isn't blowing on temperature. The water in the coil isn't moving and he is running the stove hard and that is trying to make steam. The pressure builds and poof goes the valve.

How can you tell if the water is moving? The bottom cold pipe fluctuates . If there's hot water being used the cold side can drop bellow 100 but it slowly rises back up and is often 160 .

The blow off valve is set to blow at 210 degree or 150 psi.

Are you running power to one or both of the tanks?

Lightning wrote:Are you running power to one or both of the tanks?

Power is only hooked up to 1 tank but the power has been off for a month or so. When I run the stove I shut off the power . I left it on 1x and the tank tripped out anyhow due to high water temp.

Wow. Can I see the coil itself in the stove? I have a similar hot water system like yours but very seldom have any over heating issues.

Are the two tanks hooked in series or parallel?