I have a bypass installed with ball value. It was closed during the summer, but I opened it for the winter after noticing the temp of the boiler dropping a lot when circulating hot water for the baseboards. It seems to reduce the temp drop in the boiler when the heat is on multiple zones. I also reduced the temp of the L6006 to 120 (had it set to 140 in the summer) that I have for sensing fire outage after watching the boiler temp swing with the value closed. Should I leave it full open during winter and summer?