Simple storage system for the simple minded?

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muleman51

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Hearth Supporter
Feb 18, 2008
246
SE Minnesota
I have read posts till my eyes hurt, but is there a simple system for storage. I have an adobe boiler, no other boiler on the system, I have a 1000 gallon propane tank for storage and 2 25 gallon tanks for expansion. The house has various heat system and zone valves and a sidearm hot water heater. The boiler and storage and expansion tanks will be located in an insulated room 100 ft from the house. Can this be done with one pump or do I need one pump to get heat to storage and one to get heat to house and I think I need a input protection valve. Man I wish I had bought a Garn. Help please. Thanks Jim
 
You'll need two circulators - one for the wood boiler and one for the storage. Can't get by with one, because the storage needs to be charged with top-to-bottom flow and withdrawn with bottom-to top flow.

My 'simplest pressurized storage' sticky at the top of the boiler room is the simplest I've been able to come up with. Just ignore the oil boiler and associated controls, which makes it pretty straightforward. In the simplest possible case, the load circulator is controlled by the zone valves so that it runs if any zone valve is open - you'll need a relay for that. The adobe needs a circulator that runs whenever the adobe is hot, and you should have some form of input protection - a Danfoss type thermostatic valve is probably the simplest.

The load circulator should be the same size (or slightly smaller) than the adobe circulator. I don't know the output of the adobe, but I've used a Taco 007 in this type of application. A Grundfos 3 speed circulator would be another choice for both circulators, and it would let you manually select different circulator speeds to tune the system.

Hope this helps....
 
My load pump runs all the time in a loop through the side arm and zone valves open as neededto heat various parts of the house. Do I need 2 fittings in the bottom of my tank or can I get by with the bottom withdrawl tube for 1 of the pumps.
 
My load pump runs all the time in a loop through the side arm and zone valves open as neededto heat various parts of the house. Do I need 2 fittings in the bottom of my tank or can I get by with the bottom withdrawl tube for 1 of the pumps. From your drawing I don't follow the bottom to top flow for the load , am I missing something.
 
muleman51 said:
My load pump runs all the time in a loop through the side arm and zone valves open as neededto heat various parts of the house. Do I need 2 fittings in the bottom of my tank or can I get by with the bottom withdrawl tube for 1 of the pumps. From your drawing I don't follow the bottom to top flow for the load , am I missing something.

I hope that your load pump doesn't run ALL the time. No point at all in having it run if there's no load calling for heat.

Without a schematic, I can't answer your question about tank fittings. I would assume that one would be enough.

In my drawing, consider what happens when the wood boiler is not running. There is no flow through the wood boiler - that whole loop is still. If there's a heat demand, the load circulator turns on. It draws water from the top of storage, circulates it through the load (baseboards or whatever) and returns the cooled water to the bottom of the tank.
 
nofossil said:
I hope that your load pump doesn't run ALL the time. No point at all in having it run if there's no load calling for heat.

What is the best way to have the system sense a load for a sidearm water heater?
 
twofer said:
nofossil said:
I hope that your load pump doesn't run ALL the time. No point at all in having it run if there's no load calling for heat.

What is the best way to have the system sense a load for a sidearm water heater?

A sidearm is not typically driven by a demand, and it's not typically a zone. Instead, the sidearm shell is plumbed in series as part of the main loop or as part of a loop that is active most of the time. Sidearms don't transfer a lot of BTU/hr into the DHW - they just transfer a little over a long period. By the way, if you use a sidearm you MUST have a mixing valve on the outlet of the DHW tank to prevent scalding. The sidearm can eventually bring the DHW tank up near the boiler outlet temperature - around 180 degrees. Extremely dangerous without a mixing valve. I use a Honeywell AM101 set to about 120 degrees.

In general, a DHW tank with a sidearm still has its original heat source (electric or whatever) intact as backup.
 
My pump does run continually, it heat part of the basement in an open loop and through the sidearm which does have a mixing valve.
 
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