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Central Heating Exspansion Tank Overflow Drip but Ball Valve is Fine

Postby JamieSmith » Tue Jan 16, 2018 7:35 pm

Hi, I have a dripping overflow from the CH expansion tank. the ball valve is fine and operates. i have checked the thermosat on the hot water tank and that operates and switches the heating on and off for water when at temperature.

I have noticed that when the heating is on and running there is a flow back from the bottom of the F & E tank as i can see the water flow. when i touch the water pipe at the bottom of the tank it is hot water coming back up.

the water tank is fairly new 4/5 years old, could it be that, how woudl water get back up the pipe.

the pipe that bends over the top is bone dry, so it is def coming in from the bottom.

our water pump was set to 3, so i have changed that to 2 with no difference, rads are all hot with no air?

please help
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Simply Build It

Postby Cosmo » Fri Jan 26, 2018 7:02 am


The level in your f&e tank is most likely set too high thus when the water heats up it expands. OR if you have a indirect hot water cylinder the coil may be passing. Try lowering the water first.

Hope this helps
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