My 2 element immersion heater is making a bubbling sound and hot water is overflowing into the cold water feed tank above it This only happens overnight on economy 7. I have a thermostat on each rod each set to 50c. I have been told by a plumber that the overheating is due to "two thermostats at 50c equals a water temp of 100c resulting in overheating" but this overheating never happened before.

Pedro, July 2007

what kind of plumber is he then? if he don't know a basic answer like that.
don't care if you had four set to 50 they will all still cut out at 50 degrees. not 200

you need to change the stat in the bottom immersion it is faulty and not shutting off a 50

plus your stats should be set to 60 not 50 for health reasons

hi-spec plumbing, July 2007