I have a sealed Y-plan oil-fired system that was upgraded from a gravity HW, pumped CH in the last year. I now find that, having successfully removed all the air from the system by adding a separator, there is a brief second of water hammer when the 3-way valve changes its position. This happens even when the pump, Grundfos Alpha, is at its minimum setting. What I would like to know is: will I solve the water hammer issue by changing to an S-Plan system using two 2-port valves instead of the 3-way one ? Perhaps a shock arrestor maybe the answer ?
Thanks
Alec