System design - getting close to something that may work

[MrEd]

I think I am getting close...

I've been studying piping diagrams for weeks from the many examples on this site, and finally nofossil posted this one on another thread that looks like it is the closest to what will work for me. Just what I wanted, find one that is almost exactly what I want and then tweak as necessary...

I have a few questions about this one to see how I need to customize it for my setup (or at least understand it better).

My setup is the same. Oil burner in the cellar with 6 zones controlled by zone valves. Tarm in the garage about 40 feet away. Storage somewhere in the middle.

In this diagram, I like how if all the zones are closed, and wood boiler is running, heat will be forced into the tank by default. Even with no zone valve this would be the default behavior. If all zone vales are closed, 100% of the heat goes to the tank. First question is, how to prevent the tank from taking heat when a zone is open. Do this system need a zone valve that is closed when any of the others is open, and vice-versa, or do we assume that if a ZV is open, that the tank will only steal a certain amount of the heat and the other zones will still be satisfied in a timely manner?

If you do need a "close if any other ZV is open" setup, what is the simplest electronics that would accomplish this?

If a baseboard zone is open, and oil burner is off, what prevents water/heat from flowing thru the oil burner? anything? or is it just because the tarm is "pulling" water away that it won't be wasted in the oil burner?

What/how would the heat from storage be put onto the system...I understand a ZV calls for heat, tarm is off, storage is plenty hot, what kind of electronics do you need to tell the storage circ to turn on only if the temp is hot and turn on the oil burner if it is not? Does this entire setup assume a microprocessor-like control board with C++ programming to run it all? or is there some sort of 'simple' version that I could put into use?

Where does this system need backflow/check valves to work properly?

Could someone explain the simplest amount of electronics/control logic that will make this work? I understand house electric, and plumbing a bit too, but control logic for a boiler is all new to me....

Nofossil: What did you draw this in? any chance it was done in Visio and you could make available the "raw" file for me to edit?

 

[chuck172]

It seems like you and I have started this wood-boiler adventure at about the same pace.
What is really helping me out is buying a few relays (cheap) and playing with them and a multi-tester. You'll soon learn what they can and can't do. Remember the zone valves have switches which when wired in parallel, can activate the relays.
I had to do quite a bit of re-piping to my existing heating system. I had to add some check valves also. Remember you can buy new circulators with checks built in.

 

[MrEd]

Good suggestion chuck...any links to some relays that I could purchase that I could play around with and likely to actually be used in the real system?

Also, can you give me a few real examples of something that I could do with a relay (or relays), that I couldn't otherwise? Never used a relay so I want to be able to ponder their purpose while I have some on order...

 

[chuck172]

I order from Grainger. Very fast shipping and the shipping is free if your a member of a Farm Bureau. (at least in NJ)
Grainger part # :
4DG59 socket
2XC02 120 volt relay
2W929 24 volt
Relays and sockets are cheap.

An example of what you can do with relays:

You can use a relay wired with the Tarm aquastat.
If the Tarm is 140 degrees or more, Tarm circulator is hot
If the Tarm Aquastat reads less than 140 degrees, Oil Boiler Circ. is hot.
This can be switched by relays. The relay would be signaled by the switches wired in parallel from the zone valves.
Just get a relay and play with it for a while, You'll see how they work and it all will come to you.
I'm sure NoFos and others will help you out.

 

[Nofossil]

I think I am getting close...

I've been studying piping diagrams for weeks from the many examples on this site, and finally nofossil posted this one on another thread that looks like it is the closest to what will work for me. Just what I wanted, find one that is almost exactly what I want and then tweak as necessary...

I have a few questions about this one to see how I need to customize it for my setup (or at least understand it better).

My setup is the same. Oil burner in the cellar with 6 zones controlled by zone valves. Tarm in the garage about 40 feet away. Storage somewhere in the middle.

In this diagram, I like how if all the zones are closed, and wood boiler is running, heat will be forced into the tank by default. Even with no zone valve this would be the default behavior. If all zone vales are closed, 100% of the heat goes to the tank. First question is, how to prevent the tank from taking heat when a zone is open. Do this system need a zone valve that is closed when any of the others is open, and vice-versa, or do we assume that if a ZV is open, that the tank will only steal a certain amount of the heat and the other zones will still be satisfied in a timely manner?

If you do need a "close if any other ZV is open" setup, what is the simplest electronics that would accomplish this?

The load circulator runs if ANY zone valve is open. It should be the same size as the wood boiler circ, or perhaps a size smaller if the wood boiler is oversized. It forces a goodly portion of the boiler output through the zones. If only one or two zones are open, you probably want heat going into storage as well, since the boiler can put out way more heat than one or two zones can absorb. Zone valves provide flow restriction - the more of them that are open, the higher the flow through the zones and the lower the flow through storage.

If a baseboard zone is open, and oil burner is off, what prevents water/heat from flowing thru the oil burner? anything? or is it just because the tarm is "pulling" water away that it won't be wasted in the oil burner?

The load circulator has the effect of pressurizing the hot manifold above the oil boiler. The oil and wood boiler circs both need integral check valves to prevent reverse flow.

What/how would the heat from storage be put onto the system...I understand a ZV calls for heat, tarm is off, storage is plenty hot, what kind of electronics do you need to tell the storage circ to turn on only if the temp is hot and turn on the oil burner if it is not? Does this entire setup assume a microprocessor-like control board with C++ programming to run it all? or is there some sort of 'simple' version that I could put into use?

The logic is explained in my 'simplest pressurized storage' sticky at the top of the boiler room page.

Where does this system need backflow/check valves to work properly?

Could someone explain the simplest amount of electronics/control logic that will make this work? I understand house electric, and plumbing a bit too, but control logic for a boiler is all new to me....

Nofossil: What did you draw this in? any chance it was done in Visio and you could make available the "raw" file for me to edit?

Visio. Here's a link to the Visio source file - have fun.

 

[MrEd]

OK, another question, I didn't realize the schematic I posted is really the same as the "Simplest Pressurized System" schematic, but with the components re-arranged. This one, showing the "outside/inside" layout makes much more sense to me because it closely mimics the parts I already have in place...

Anyway, I really like the concept, but can you explain better why its better to have a "Load circ" (as you call it), that is always on when any ZV is on, instead of just having a storage circ that goes on when heats being pulled from the tank? Basically it would just move that circ out of series with the other circs, and the way I envision it, only one circ would ever be running - either wood, storage or oil and all three would be in parallel.

You probably have a good reason why you did it your way, but it seems to add complexity...what am I missing?

 

[Nofossil]

You're right - a dedicated storage circ would be a little more efficient. In fact, that's the way I do it. It's quite a bit more complex from a controls point of view, though, and requires an additional zone valve. Unless you get really sophisticated, it doesn't deal well with part of the output going to storage and part to loads.

My 'simplest' posting is just that - the simplest approach that I could come up with. I actually think it's better in many ways than a lot of more complex approaches, perhaps including my own. If I ever go with pressurized storage, I think I'll go with something very close to the 'simplest' approach.

Here's what I'm actually running right now. I'm also in the process of transitioning to a tankless DHW heater to replace my oil boiler.