Please help!! Combi problems

[danieldav]

Hi - im new to the forum but hoping someone can help? I have an Ariston MicroCombi boiler and for some reason i have water passing through the system, i spoke to a few people and they said to change the filling loop, i changed this and it didnt resolve the issue, still had water coming through the overflow and the Pressure up and above 3bar, so i was then told to change the PRV valve which again i did and still this did not solve the problem...

I have now had to turn the mains water supply off to the house as whenever its on the boiler pressure is rising to about 3.5 and you can here the water passing through the boiler and overflow flowing with water outside...

Any ideas??

 

[kevplumb]

secondary heat exchanger is passing then

 

[xr4x4]

The filling loop should be turned off, is it?

 

[danieldav]

Kevplumb - Secondary heat exchanger?? is that expensive?

xr4x4 - Filling loop is turned off yes..

 

[xr4x4]

So if you turn off the water, does the pressure drop on the gauge?

 

[danieldav]

No when i turn the mains off the pressure remains as it was until i drain the system again...??

 

[ServiceNumpty]

As a test, turn off cold water isolating valve under boiler, drain boiler to 1 bar pressure. Leave overnight if it hasn't risen as Kevplumb said plate heat exchanger replacementis required.

 

[danieldav]

KevPlumb - Is that the same as the HDW switch/valve?

 

[Agile]

No, its a part which transfers water from boiler into hot water.

That failure is pretty rare on your boiler model though.

Part may cost about £80.

Tony

 

[bengasman]

Which parts did you change exactly?