Pumping away & PD thru boilers

hr

you might need some checks or flow checks on those PS connections. Not sure if you have check circs or zone valves out of the picture.

That LWC might cause you fits on that dead end. Might be better to put a tee to the left of the Spiro so the probe is in a better "wet" location. Maybe that air vent will keep it wet?? A nuisence lock out would be a drag :( I prefer to see 'em in a horizontal position so they can't get an air bubble around the probe.

I like the position of the Taco box. Makes it easy to see those nice lights.

hot rod

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Mark @ Radiant Works Inc

Pres drop thru low-mass boilers

When using low mass, high efficient boilers, the manufacturer recommends pumping into the return in order to overcome the high pres drop through the boiler. When doing this with a primary-secondary system, will the pres drop through the boiler create problems at the jct of the primary/secondary piping, if the head pressure of the secondary loop, is greater than the head pres on the primary loop after going through the boiler. (the expansion tank is located at the suction end of the circ)

Tony_23

Head

Is resistance to flow, not a pressure to overcome. The heads of the primary and secondary do not affect each other, that's why that piping arrangement is used.

Your pic isn't large enough to include the piping to the right of the mixing valves. I can't tell definitively if that's P/S. Might be, might not.