will this simple plumbing plan work?

[infinitymike]

I want to keep my initial plumbing costs down as low as possible.

I want to hook up to my EOB in series temporarily because it is old and I dont want it to stay cold for long periods.
I'm willing to sacrifice the btu loss for now.
Later I will replace it and then plumb in parallel.

I have a tankless DHW coil in the OB and I bought one for the Wood Gun as well, realizing I could have bought a indirect storage tank.
So now I will just buy a buffer/storage tank.

Will this simple plumbing plan work.
Basically I'm just cutting the heat loops and sticking the WG in between.

Should there be more valves, circulators or any thing else.

The next question is the wiring.
Do I just tap into the t-stat wire off of the EOB and run it over to the WG?

EDIT

Forget the first design HOWS THIS ONE
oops forgot the expansion tanks and probably some things!

 

[ewdudley]

Sorry Mike, just can't read it.

 

[infinitymike]

Sorry Mike, just can't read it.

Cant read it because of picture quality or because it drawn in such as it doesn't make sense?

 

[ewdudley]

Sorry Mike, just can't read it.

Cant read it because of picture quality or because it drawn in such as it doesn't make sense?

Sorry, should have been more specific. Turns out I couldn't read it on the monitor I was using at the time, now I can make it out pretty well with a brighter screen (but won't be able to study it until tonight).

Cheers --ewd

 

[maple1]

Off the top of my head, I don't see how your DHW tank will get hot again if it cools off - unless it is electric, or you just turn the hot water tap on and let it run until the hot makes it through again (a whole tank of cool water?). I might think about not using a DHW tank at all, and just running DHW thru the oil coil then the wood coil to the tap (in series). Or maybe vice versa might be better, if you'd be using the oil for DHW when your wood fire is not burning.

EDIT: Also, you should be able to use just one circ for both zones - one pipe & circ between wood & oil, then split the supply after the oil to two pipes with their own zone valves, one for each zone. Or maybe you don't use zone valves, just the circs?

 

[Gasifier]

Mike, I am not sure if I am understanding your drawing or not. The buffer/storage tanks we are using store the hot water from the boiler for heating the house or then going through a zone to heat the DHW in an in-direct tank. That water never mixes with your DHW for showers, sinks, etc. Others use a coil like you said you have. So if you have a coil in your oil boiler and wood boiler what is the water storage tank for? If that is not heated, like Maple said, it will cool down and then only be reheated when hot water off of your coil is going to it again. But in the meantime you will be getting a lot of cool water from it if it has cooled down. Wouldn't your system work with out the DHW storage tank? Just make sure there is a mixing valve somewhere before it goes to supply everything in the house so the water is only 110-120 °F . Again, I am a rookie, so maybe I am missing something or not understanding your drawing. I would still suggest that the buffer/storage tank be used, but just for heating house. It allows your boiler to crank out the BTUs and then saves them for you. Insulate it well. Let us know what you decide and good luck man.

 

[maple1]

Also (again), I don't think you'd need a circ in your DHW flow - water pump pressure (or water main if on town water) just pushes that thru when the tap is turned on.

EDIT: also think you'll need a tempering circuit between your supply & return on the wood unit.

 

[infinitymike]

Off the top of my head, I don't see how your DHW tank will get hot again if it cools off - unless it is electric, or you just turn the hot water tap on and let it run until the hot makes it through again (a whole tank of cool water?). I might think about not using a DHW tank at all, and just running DHW thru the oil coil then the wood coil to the tap (in series). Or maybe vice versa might be better, if you'd be using the oil for DHW when your wood fire is not burning.

EDIT: Also, you should be able to use just one circ for both zones - one pipe & circ between wood & oil, then split the supply after the oil to two pipes with their own zone valves, one for each zone. Or maybe you don't use zone valves, just the circs?

I was thinking of an electric DHW storage tank and I assume they are insulated. So my thought was that this would hold the hot water created by the coil in the wood or oil burner. I didnt think it would lose a lot of heat while in stand by. But if it does wouldnt the electric kick on?

I dont have zone valves on the existing oil burner. One supply line comes out of the top of the unit and tee's off to the 2 zones.

i know my pic isnt drawn like this on the wood side but both zones would come together with a tee and then one pipe into the wood gun as well as one pipe out and another tee.

I realized after I posted it that I dont need the circ or zone valve for the DHW but probably need back flow valves at the wood side. Right?

 

[infinitymike]

Mike, I am not sure if I am understanding your drawing or not. The buffer/storage tanks we are using store the hot water from the boiler for heating the house or then going through a zone to heat the DHW in an in-direct tank. That water never mixes with your DHW for showers, sinks, etc. Others use a coil like you said you have. So if you have a coil in your oil boiler and wood boiler what is the water storage tank for? If that is not heated, like Maple said, it will cool down and then only be reheated when hot water off of your coil is going to it again. But in the meantime you will be getting a lot of cool water from it if it has cooled down. Wouldn't your system work with out the DHW storage tank? Just make sure there is a mixing valve somewhere before it goes to supply everything in the house so the water is only 110-120 °F . Again, I am a rookie, so maybe I am missing something or not understanding your drawing. I would still suggest that the buffer/storage tank be used, but just for heating house. It allows your boiler to crank out the BTUs and then saves them for you. Insulate it well. Let us know what you decide and good luck man.

No the storage tank is not a regular storage tank.

I would use an electric dhw tank. so in the summer if I choose not to burn it would kick on. Also i assume that the coil in the wood gun would send hot water to this tank which should be insulated and hold the water hot for a while.

Yes there will be a tempering line for the return to the wood gun as well as a tempering valve for the dhw.

 

[infinitymike]

can anyone help

 

[Clarkbug]

Mike,

I see that you have the oil DHW coil also hooked up as well as the WG DHW coil. Are you intending to still burn oil during the winter for heating your domestic water? I would think that if you have an electric tank, you would leave that on, heat the incoming feed with the WG, and just disconnect the feed line from your OB.

Also, I would be a little worried about your tempering line. If I am reading that right a slug of cold water thats in your house could come in and hit the wood gun. I know you have that line there, but is the intent just to have the cold water bypass the boiler? Im not sure what keeps the water flowing through the boiler as it heats up, since you are pumping towards the OB.

If you add a backflow/check valve to the DHW line, make sure you put a potable water expansion tank in place.

 

[stee6043]

I have my coffee now and this seems like a good way to start the day!

Your layout is a little confusing to me only because you are using similar graphics for both warm street water and hot boiler water. It took me half a cup to get past this. ha.

I think I would tee your DWH supply from the oil boiler in before the wood gun coil, not after. Or perhaps install shut offs on the oil burner DHW loop for winter operation? I'm not sure you're going to get proper mixing from your DHW loops without some kind of shut off on one or the other (or both so you don't heat the woodgun in the summer).

Why two circs and two lines on the supply from the woodgun (I assume those circles are circs)? Seems like one properly sized line would be better than two. For best longevity of circ pumps they should be installed on return side (lowest temp) and at the lowest point of the system as possible. Many folks will install it right at the boiler return AFTER the Danfoss/mixing valve. Any system return should be forced through the Danfoss valve to avoid the situation Clark mentioned.

Perhaps a round two sketch is needed? For ease of reading I'd recommend drawing all supply (hot) off the top of your appliances and return (cold) off the bottom. And perhaps do something different to show DHW flows. Add your expansion tank, pressure relief and circs. Many pro's recommend a full-port ball valve on both sides of every circulator or any other device you might need to service in the future. They are also very useful if you need to isolate heating loops during operation. Make sure you add vents at the high points (more than one will make your life much easier). A place to hook up a garden hose for filling is also useful.

You probable weren't looking for the little details. Hopefully some of it helps. I'd redraw, simplify (reduce supply lines), add in your devices and repost. It certainly looks like a good start.

 

[Clarkbug]

My guess is the two circs and two supplies were in place because the original system used one pump per zone. So, when a pump turned on, it would flow that zone only. But it looks like the WG is going in the middle of those zones. Stee brings up a good point here, that you would need to move your circ pumps to be before the WG, and then you could have a single line from the WG back to the oil boiler.

If installed the way you have drawn, you lose the ability to have separate zone control, since when either pump runs it would pull/push through both of the house zones.

 

[Hunderliggur]

I agree with the redraw. I think want is needed here, for a "simple" hook up with low initial plumbing costs, is to add the WB after the output of the OB with a set of closely spaced T's and add a dedicated circulator to force the water into the WB return (after a Danfoss of course). No storage is not my design experience so I am a little concerned with boiler overheat if there is no zone load. The control wiring could be such that if the WB is producing heat the OB does not fire. Ideally, if you could plumb the OB with its own closely spaced T's you would not be running water through either of them unnecessarily. Right now, electric is cheaper to heat DHW than an OB (or tankless high efficiency propane for that matter). I would shut off the OB water heater and preheat the water through the WB and top off the heat in the Electric water heater.

Good luck, ask questions, and take your time. Don't rush it.