Plumbing

[maple1]

That seems odd - all thermostatic valves I have seen are right at the boiler. Even mounted on the back of it, if it's an OWB. With the underground heat loss, I don't think it's doing it's job correctly & the boiler is getting return water that is cooler than it is supposed to be.

What you said about the manifold should work unless I'm still missing something - each boiler circ would simply turn on when it needs & calls for heat, shouldn't be any 'balancing' needed. You would need a supply manifold, and return manifold. Also have no idea what your existing controls are either - so that might need some work too. And still don't know about pumping at each indoor boiler. Might need some flow checks but might already have them?

 

[Bill322]

If I do a manifold setup the 2 circulator would run 24/7 as to keep HX up to temp so when any zone calls the HX would be hot. All my returns flow through their respecting Has. The TV doesn't mix return water only activates or closes when supply water drops in temp

 

[hondaracer2oo4]

Bill

Something like this

https://www.google.com/url?sa=i&rct...ZZMsUU0bgN7For5PhtAyo1Ig&ust=1489073544929246

Think of the conventional boiler in the pic as your wood boiler and those closely spaced Tees would be the secondary loops to each boiler in the house. The pumps on those secondary circuits would only turn on and run when a thermostat going to the respected boilers called for heat, it would turn the pump on and send water to the hxs.

 

[Bill322]

From what I've been reading that way takes up a lot of space and I'm limited on that. Also wouldn't the inside boilers fire for a little while as HXs wouldn't be up to temp?

 

[maple1]

The TV thing is getting a bit of a sidetrack - but TVs don't usually mix return water per se, they cut it off & bypass the supply back to the boiler. Just seems that the heat loss underground in the return line would result in colder water than desired making it back to the boiler return, with the TV at the other end of the underground. Not an issue with very good underground pipe, but would be a vulnerability with much heat loss from anything less than very good piping & could increase corrosion potential back at the boiler. If CB says inside, I guess that's their call.

Do you know how much head loss that TV is presenting? Could it restrict flow on your new underground piping?

Anyway, talking the manifold thing - if you are running circs 24/7, that should only need to be the one circ at the OWB that supplies the HX, to keep the HX up to temp. The two circs at each indoor boiler would only start when that boiler needs heat or when that part of the system calls for heat. Which may or may not turn out to be most of the time depending on heat demand.

 

[Bill322]

From what central boiler says TV doesn't present much loss but i will be up sizing mine to 1.25" when I redo underground pipes. If I wire 2 indoor pumps to run only when heat calls hx2 wouldn't heat up for awhile as it's 50 feet away and it would have to pump all that cooler water thru hx b4 heated water would arrive. So I guess I don't understand that approach or maybe I'm missing something or misunderstood

 

[hondaracer2oo4]

Bill, 1 inch pex holds 3 gallons per 100 feet. If the water has 50 feet to go that is 1.5 gallons in that 50 feet. That means at 7 gpm or so it would take about 12 seconds for the 180+ degree water to reach the flat plate 50 feet away, not to mention the water is probably never going to be below 130 or something because the boiler will be calling for water often enough.

 

[Bill322]

Bill, 1 inch pex holds 3 gallons per 100 feet. If the water has 50 feet to go that is 1.5 gallons in that 50 feet. That means at 7 gpm or so it would take about 12 seconds for the 180+ degree water to reach the flat plate 50 feet away, not to mention the water is probably never going to be below 130 or something because the boiler will be calling for water often enough.

Ok so that does make sense. So do we think this is the way to go? And if so what size circulator? 007? I have 2 spares right now. Now just will have to figure out wiring but that shouldn't be a problem

 

[Bill322]

What is the difference in just adding 2 circulator 1 for each HX to the way it is plumbed now?

 

[hondaracer2oo4]

Bill, that would be in conjunction with 1 1/4 supply line into the basement. We know you don't get enough gpm to the house. After that is solved we can talk about how to split the flow between the two boilers. I would still like to hear about someone expierenced with balancing valves placed on each of the two circuits to balance the delta t across each hx. Even though it is warm out you can still test balancing the two circuits with the ball valves to see what you can do to balance the temp drop across the hxs. Just crank all thermostats in the house to 80 degrees so everything is calling from both boilers then balance the valves to achieve the same temp drops across each hx.