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Overflowing central heating header tank?

Postby ddentrec » Mon Feb 21, 2011 6:17 pm


I am living in a 10 year old house with gas central heating. Over the past 6 weeks I am hearing an intermittent loud (metallic?) banging or rumbling noise from the loft. It lasts about 10 mins with no obvious pattern.

Today it happened again and I noticed the overflow pipe was gushing with water (not sure if this was from hot water feed, or cold water feed tank as it all stopped by the time I could get into the loft!!!). The loud noise was definately coming from the direction of the hot/cold water tanks and was possibly caused by the water rushing though the plastic overflow pipes which rattle a bit. The central heating was on and there was also faint metallic 'tinkle' sound coming from the downstairs radiator.

I went into the loft, noise has stopped, and noticed the cold tank was full, and the hot water feed tank was also full and very warm to the touch.

Heating system seems to work fine.

Any ideas?! Your help will be much appreciated so I can understand the problem before calling out a plumber.
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Simply Build It

Postby stoneyboy » Tue Feb 22, 2011 8:32 pm

I suspect you amy have more than one problem because both cold water tanks are not as they should be. I can only suggest that the coil in your hot water cylinder has perforated and your boiler is furred up causing the water in it to boil. Other forum members may have alternative suggestions but I suspect it is going to be an expensive time for you.
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Postby uk_ducati » Wed Feb 23, 2011 7:29 pm

Sounds like the water in your hot water tank is boiling and it is venting into the cold water tank in the loft. There are a few possibilities. The tank thermostat could be stuck on constantly heating the tank another possibility is a zone valve or 3 port valve is stuck open or the immersion heater is stuck on. A temp fix to stop it from happening until you can get a plumber is turn the thermostat down on the boiler so the water isn't so hot

Hope this helps

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Postby ddentrec » Thu Feb 24, 2011 7:20 pm

Thanks stoneyboy and uk_ducati for your excellent feedback. This makes a lot of sense. I just need to prepare my wallet :P
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Postby ls20 8qq » Sun Mar 06, 2011 7:39 pm

maybe the heating system is blocked and needs flushing or the pump is set to high. could also be the boiler stat not working ..would need to look at it to know for sure
ls20 8qq
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