The problem I have is with the pressure dial on the tank in bathroom. I was told that both needles should be at about 1.5, but the red needle rises up and then we have madly banging pipes, and rattling, and even when we release the small taps on the pipes, it can take a while to lower the needles to level. Also, this always trips the boiler out. Is it because it is very cold? We have had this system for about 2 years, and the problem is only intermittent.