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Hot Rod, I have followed the pictures from idronics #10 page 29 figure 6-14. How does the boiler fill when piped like figure 6-14? The fill water enters on the return header next to the separator it goes through the return of the separator to the boiler return. Between the boiler and the return header is the Thermostatic anti-condensation valve. That valve prevents any water below 140* from going to the boiler. On the boiler supply side water leaving the boiler passes through a check valve. That valve prevents any water from getting to the boiler on the supply side.
The picture shown of the automatic fill and back flow preventer shows a shut off valve on the supply side . When I installed my Caleffi auto fill and back flow preventer I decided to read the directions, they are so simple to install reading directions is a waste of time. The directions said to install a shut off valve on both sides of the auto fill and back flow valve so the valve can be serviced. I said that makes sense and followed the directions. I wonder why the back flow auto fill is not pictured like that in the Idronics journals.
I am thinking about running a hose from a water supply either to the boiler drain or else to the drain port on a isolation valve to fill the boiler to the correct pressure.
Do you have any ideas or thought on this. Or did I screw up somewhere.