Plumbing to and from garage..?

[chew72]

I'm in the process of buying a house and planning out the heating system. We are doing a major Reno so the heating system can be what ever we want. We are planning on hot water rad (stelrad), infloor in the kitchen, bathroom and basement as well as DHW. Also there is a shop/garage that will have in floor radiant. Down the road we'll have a wood boiler in the shop with storage.

The problem I'm having is how keep the plumbing simple and allow the boiler in the house to heat the shop when the wood/storage is cold. Any ideas?



Edit: The diagram is just for the main boiler loop. So the in floor will have mixing valves etc that are not shown.

 

[ewdudley]

That all looks good.

But need a check valve between the tee at the top of the vertical leg coming up off the top of the 500 gallon tank and the tee that feeds the the shop in floor. Without the check valve, when the house boiler is feeding the buffer tank, colder water would tend to fall through the 500 gallon tank and would pull hot water over to the 500 gallon tank until the hot water level was the same in both tanks.

Also in the same section as the check valve discussed above, need a zone valve or a manual valve that will force the shop in floor pump to pull all the way from the buffer tank when the wood boiler storage tank is not on line. Without a valve there would be a parallel path through the 500 gallon tank and the shop in floor circuit would not necessarily be able to get enough hot water from the buffer tank.

An entirely different approach that would work very well would be to have the shop in floor circuit draw from the line that comes from the bottom of the buffer tank somewhere to the right of the pump that brings house return water to the bottom of the storage tank.

Then to the left of the point where the shop in floor circuit draws place a check valve, and then let the shop in floor circuit return to the left of the check valve.

This way the shop in floor circuit pulls 'spent' water from the bottom of the buffer tank that will normally be plenty warm enough for in floor radiant purposes. If for some reason it is temporarily too cool for in floor radiant the circuit continues to call for heat until cool water at the bottom of the buffer tank is depleted and hotter water reaches the bottom of the buffer tank.

This would do away with the need for a manual valve or a zone valve to force the shop in floor circuit to draw from the buffer when the wood boiler storage tank is off line, plus it would help minimize the return temperature to storage, which means increasing the amount of heat that can be stored between burn cycles.