hi people im new here, i have fitted a shower pump to pump the hot water in a house the shower pump is a whole house pump and is working fine the problem i have is the cold water tank on top of the cylinder( fortic tank) is getting warm water in it and then overflowing, would you say i needed a anti gravity valve fitting on the 22mm distribution pipe or could this be the hot water getting to hot and venting? answers soon as would be great