Expansion tank overflowing

Dreamscometrue

Hi,

Over the past week or so water has been flowing out of the overflow for the small expansion tank whenever the water is heating. I've taken a look in the loft and the water is hot. I've noticed that the hot water has been very hot out of the shower recently. I've just this minute turned the boiler thermostat down. Both tanks are full to the brim. At this very moment it's not dripping! I'm guessing that it can't be the float valve as the water in the tank is hot? Praying it's not the cylinder as I can't afford a new one and that would tip me over my overdraft limit. Helllllllllllllp!!! Thanks in advance.

southcoastrgi

Empty it out the water when cold should only be 1" or 25mm above the outlet, adjust/replace the ballvalve if needed, then see what happens

Dreamscometrue

Just washed my hair & the thing is dripping onto the patio again. Will go to Screwfix tomorrow to get a new valve. I replaced the one on the main tank a few years back so fingers crossed that bit should be fine.

southcoastrgi

Needs to be a Part 2 brass ballvalve

Ectophile

Check that you haven't got an immersion heater that is stuck on. Given enough time, an immersion heater that won't turn off can boil the water in a hot water tank.

Dreamscometrue

Ectophile wrote: »

Check that you haven't got an immersion heater that is stuck on. Given enough time, an immersion heater that won't turn off can boil the water in a hot water tank.

Thanks. Definitely not that as the immersion has never worked & the fuse box makes a huge bang if anyone mistakenly switches it to the on position!

markin

If its got hot water in the tank im not sure it is the ball valve, it should be easy to spot if its just that.


Guess in the dark, A blocked pipe or the coil is leaking into the tank? How old is it?


Is the tank thermostat working correctly?

Dreamscometrue

Got the bits from Screwfix & changed the float valve. Turned the water & fired the boiler up for the hot water. No leaks & the valve shut off at the right point. It had a minor drip before. Unfortunately hot water started spouting from a copper pipe into the tank coming from the cylinder I suppose. I shut off the boiler for a while to let it cool a bit. Adjusted the boiler thermostat again. It was originally at 6 and is now at 3, Put the boiler on again for the water. I might even move it down a tad more as the water temp was fine when I had a shower. I believe it has stopped dripping for now. Hope the patio is completely dry by morning. Glad I changed the valve anyway as did have a minor drip and was ancient but seems to be a boiler thermostat issue?

FreeBear

Dreamscometrue wrote: »

but seems to be a boiler thermostat issue?

That would have been my first suggestion. But as in post #7 - Is the thermostat on the tank working properly ?

If there isn't a thermostat on the tank, it is well worth fitting one - It will save quite a bit on gas and is a simple/cheap thing to fit.

markin

Also if you have valves on the rads and they are all closed the water has to go somewhere so also try a lower pump setting.


Having the boiler thermostat set at 6 seems over the top who set it?