Boiler making rumbling sounds

[raj]

Hello,
we recently started to get rumbling noises from the immersion heater tank, in the airing cuboard. After a while it goes away. I took the precaution of turning down the heating. Anyone have any ideas? We have a IMI Flowmax unvented cylinder. It looks like it is a few years old. it came with our house, which we have been in for just over a year. I should confess, I no nothing about boilers. Could it be air in the system somewhere? Please help, the rumbling noise sounds like the boiler might go bang!! If anyone had similar problems, please let me know what to do!!

 

[breezer]

i am not a plumber or heating engineer, have you checked the tank in the loft? is it full of water (it should be) and does its ball cock work? (they sometimes jam closed)

 

[masona]

I had a similar problem.Could be your boiler thermostat need replacing or cleaning. I took the boiler thermostats apart and blew out the dusts & hoover and turn the setting slightly down.It's now okay ! I think what happening, the boiler is overheating the water too quickly and therefore expanding to the expansion tank via the vent. I also turn up the pump setting to number 3 to speed up the water flow to reduce overheating. This is the cheapest way of finding out !