Vokera Linea 28 Pressure Falling

[Sarah2]

Hi, my boiler pressure keeps dropping. I am having to top up more than once a month which I know is not a good thing. I have had another problem with the boiler recently and last week the engineer told me that everything was OK and when I said that I had noticed the drop he just asked if we had any leaks.When I said 'no' he gave no further advice. The boiler is regularly serviced and we have no leaks at all in the system and apart from this pressure drop and the water upstairs not being as hot as I would like, no other issues with the heating.
Any ideas please...

 

[gas4you]

Have you checked the prv pipe outside? Is it dripping?

Tape a plastic bag over it for a while to check.

If the prv isn't letting by, then it will have to be a leak on your system somewhere.

Have a look at the auto air vent on the boiler, these can dribble constantly when scaled up and stuck.

What pressure do you set the boiler to when you top it up?

Normally I would suggest isolating the boiler from the heating system at the valves under the boiler, but in your case I would almost guarantee the valves would leak if you moved them, then you would have around a £100 bill to replace them

 

[twgas]

pressure dropping means water leaking, whether it be a pipe, a valve, the boiler or whatever. The leak may be too small to be easily found, if all obvious candidates have been checked, (including taping a plastic bag over the pressure relief pipe) I would try adding some leak sealer to system and see how it goes.

 

[nickso]

if its not the suggestions above and you have checked all the rad connections etc then get the heat exchanger checked, very common leak and its obvious to the trained eye that its leaking.

its an easy check yourself if you feel confident enough to undo 2 clips.

 

[Sarah2]

Hi,
Thanks, I will put a bag over the outside pipe but we have not noticed any dripping before. We fill the boiler up to 1.5 ( we notice that the pressure dips slightly when the heating is on but then lifts again) We have an anti scale device fitted to our cold water pipe to cut down on scale too.
The boiler sits on the wall in the kitchen so surely we would notive any leaks from the boiler itself if they were happening?? Our house is old and small
We keep the topping up 'loop' attached to the boiler all the time - could that cause any problems ??
How much water is being lost when it drops from 1.5 to 0.5? - just so I have an idea.

 

[nickso]

if the heatex is leaking you wont see any water as it gets burnt off by the flames and heat inside the combustion chamber.

pressure may dip slightly when the boiler comes on due to the pump. if the pressure lifts up to 2.5-3 bar then there is an expansion problem.

there is no way of telling how much water is lost when the gauge drops. each system is different.