In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Twin boilers, two circs, 1 zone, 1 circ fist stage, 1 circ 2nd stage, 40 psi relief valve on both boilers. 4 floors of heating w 2 indoor sensor on each floor which is averaged w 1 t stat on first floor boiler in basement, circs on return when boiler is at 130 degrees pressure is at about 12 psi and when at 160 is about 25 psi. For some reason when a-stat set for cold start relief blows off when it makes temp at 180 when I have it set for 160-180 relief doesn't. There's no real problem I'm just curious if anyone had any ideas why this is so.
Thanks in advance.