There is a small but constant leak from the diaphragm of this boiler, now for nearly a year, I think it is getting worse (faster) ! It is right infront of you when you open the front cover (and then front panel). A plumber who was doing something else at my place said it is from the diaphragm and not the little black electronic switch attached to it (it seems it comes from between the two !).

My question is, can I buy the part and change it myself ? Is the water circuit, that diaphragm is part of, is pressurized ? Is is a matter of turning off the main and simply openning and replacing the part or is it more to it ?

Thanks in advance.

Austin, June 2008

OK, I had a look. I think it is leaking from between the Domestic Hot Water (D.H.W) Micro Switch and it's diaphragm (there is another assembly very similar to this that is for heating and that is fine). I opened it and cleaned it a bit. The "Securing Clip" is rusted but the washer seems to be fine once cleaned. I wondered why there is water behind the diaphragm (is the diaphragm faulty !?).

The switch works fine but after cleaning and putting it back there is still a leak. So next step is to get a new switch and securing clip (it may or may not be the guilty party but this bit is easy to replace).

If that doesn't fix it then I might need to get the diaphragm, which is more difficult to replace.

Anyone knows if the part that goes faulty and leaks is normally the Micro Switch or the diaphragm ?!

Cheers,

Austin, June 2008

Thank you for the reply, I had another look in the manual and it seems there are 2 micro switches, very similar and with diaphragm behind them. One for hot water and one for heating it seems. I need to check to see which one is exactly leaking.

Also in the manual it only gives the part number for the micro switch, from the picture it doesn't seem to include the diaphragm. I wonder if the switch is the only part changable/servicable, or does the diaphragm comes with the switch.... ?! Not sure. The switch works as the boiler works fine. In any case I am not sure where the leak is from, where does this normally leaks from, the diaphragm or the micro switch ?! (or between the two, whose fault is it !!??)

Cheers,

Austin, June 2008

yes it is under pressure of the system, no you dont need to turn off the mains, just the flow & return isolators under the boiler, then bleed the boiler water down (use drain screw, not safety valve) the replace diaphram, you'll get it from your local merchant, part number is in your installation manual.

T, June 2008