Low pressure/ Humming noise every so often/ Boiler works fine when heating on

[lightsaway]

Hi

I hope someone can help one with this one. At this moment of time my boiler is not playing ball with me and a issues keep popping up.

* Every time the heating is off the pressure in the boiler keeps dropping, and we have to fill it back up again as the red flashing lights come one. ( daily now)
* Certain time when we flush the loo, a humming noise starts appears and im sure it coming from the loo and boiler.

* when the heating is on pressure is fine and everything is run happily. I have had it served a few weeks, and since that point the above started to really take off, before that the both issues were around Humming loo and having to fill the pressure back up back it was like every 7 - 12 days)

Can anyone tell me what could be wrong? Did I get a cowboy in to do a serving?

I hope you can help

Cheers

 

[Dotty]

Is this a new installation? A new boiler on an existing installation or just an existing installation?

Do you have a combi or a system boiler?

 

[Simon F]

when the heating is on pressure is fine and everything is run happily.

what do you class as fine?
what pressure do you fill to cold?
what pressure do you get to when hot?

 

[lightsaway]

Is this a new installation? A new boiler on an existing installation or just an existing installation?

Do you have a combi or a system boiler?

* existing installation for about 8 years
* Combi Boiler

what do you class as fine?
what pressure do you fill to cold?
what pressure do you get to when hot?

when cold, I fill it to Green area, anywhere between 0.5 - 1.5. I do not add anything when hot

cheers

 

[JCplumb]

The humming noise when flushing the loo is the valve in the loo, nothing to do with your heating. As for the combi losing pressure it could be a few things, get a gas safe engineer to come and have a look at it. Depending where you are one of the GSR's on here may be able to help.

 

[lightsaway]

we had it served and it got worse, also The humming is coming from the boiler aswell as the loo when it flushing, when the boiler is running hot water etc..

 

[SimonG]

Do you have water leaking from the pressure relief pipe outside?

 

[DalesPlumbing]

Slightly loosen off the big nut on the ball valve to the cistern.. 'Slightly'
This cures the humming 80 percent of the time.
The pressure drop is either the PRV letting by, a leak on the system or expansion vessel needs changing/recharging.
Check the small pipe that is outside generally around a metre underneath the flue.
if there's water dripping from it then you need an engineer to replace..
The two problems aren't connected..

 

[Howsie]

we had it served and it got worse, also The humming is coming from the boiler aswell as the loo when it flushing, when the boiler is running hot water etc..

If the service made it worse then get the people that serviced it back.