Overflow pipe had water coming out-why?

[MrMrMr111]

We have a back boiler system, with a tank upstairs in loft.

There is an overflow pipe I presume from the tank, tbh never noticed it outside before. The overflow actually now flows onto conservatory roof.

However never heard it flow before but this afternoon for unknown reason I heard what sounded like rain on the conservatory roof, I rushed out (as had washing on line!!) thought it was rain but it was the overflow pipe with water coming out.

What could cause this? Why now? Should I go into the loft and check it out? Nervous why it should do this, can't be 100% but I don't think it's done this before.

Very nervous also as going away soon and have visions of a flooded house?

Thanks

 

[longdogs]

The first thing to check is whether the float valve is shutting off properly. If the tank is still full up with water, bail some out and lift the float by hand. If its not shutting off you need a new one.

 

[MrMrMr111]

it only went on for a few mins to be honest, I then switched off the water and switched n the hot tap. It hasn't happened since.

So do you think it was just a one off? it was going to overflow - why?

Its a ball ache to go and check the tank, suppose I will have to, its just its in the loft, and awkward to get to

 

[Burnerman]

By using the hot tap, you have reduced the water level in the tank so the overflow stops......there's every chance it will return though - and the first sign is in the morning when the hot water hasn't been used for a while.
The overflow should prevent any nasties of course, but do get it checked out.
John