Need your thoughts.

SeanBeans

Gravity hot water system.
New cast iron boiler.
Primary secondary piping.
Side arm off of this boiler.
....pool heater off same boiler.

Please chime in with whatever your thoughts are!!

How can this be done right and safely

Zman

Why not mod/con boiler?
Primary secondary for sure.
Smart mixing valve with outdoor reset on gravity side.
Pool heater and circ should be separate from gravity.
Do you have a sketch of what you are thinking?

Ironman

Load calcs for both the house and the pool are necessary. Unless it's a very larger load for the house, the boiler may not be sufficient for the pool.

Using a CI boiler to heat a pool is not a wise choice and will require boiler protection controls. It will also require the chimney to be properly lined and insulated. A mod/con would be less expensive and more efficient.

Zman

@SeanBeans I did a similar project up the hill from you with snow melt, radiant space heat and outdoor pools and hot tubs. We estimated the switch to mod/con would save them 20%. When we saw the actual year over savings it was ~32%.
Send me a PM if you want to a copy of the design.

ChrisJ

I could really go for some bacon right now.