Boiler leaking slowly cold water

[Glen10]

Hi, I have a biasi m90e24s boiler. 4 weeks ago it started a slow cold leak. I realised because the system was empty. I went... filled up the system... bled the radiators... and then when I returned to the boiler I saw the leak. I then gave it another blast thinking I'm going to have to fill this up until I can get a plumber, and the leak stopped. Now all of a sudden, the leak has returned. Really not got a clue about what's going on. Can anyone help?

 

[jtsplumbing]

To be honest no one can help with out seeing it, you need to call out a boiler engineer, put on your location, someone of this site may be close to you.

 

[Glen10]

Ok, thank you. I was wondering if anyone had any idea why it stopped for a chunk of time and then started again. I have an engineer coming later today, but was wondering if someone would have an idea so I don't stand there looking completely gormlus. My area is Cheshunt, Just north of London.

 

[Riley]

With the greatest of respect Glen they really aren't good boilers unfortunately. It could've just been luck that you blasted a bit of muck into the thread that was leaking. I think it will have been fluke rather than anything else

 

[Glen10]

That sounds exactly like what I would have done. I had no idea what I was doing and just hoping to get it through the evening. Then funnily enough it stopped. Hopefully it's just a washer or something like that which needs replacing. We're planning on selling and moving in about 6 months time!

 

[Glen10]

Just an update... I took a plumber (gas engineer) up to see the boiler this afternoon. When we got there, there was no leak anymore. The bucket under the boiler has a small amount of water in. But nothing was coming out of the boiler. We switched the boiler on, turned taps, let it cool down and did almost everything else... and no water came out! So I have no idea why it's no longer leaking! He opened up the boiler and it looks like it's either coming from the diverter valve or the return loop valve. But he had no idea why the water was cold, because in both instances it should be hot! So we're all confused at the moment.

 

[jtsplumbing]

Take it the boiler is working ? was there any sign of rust marks inside ? any heavy rain last night ? could be rain water running back into boiler from flue !!

 

[Glen10]

I'm not sure there was much rain last week. There didn't seem to be any sign of rust anywhere either. Had I not seen it with my own eyes I would be convinced I was making it all up! The boiler is working all fine as if there isn't anything wrong. I wouldn't be bothered about it, except every 2 or 3 weeks it seems to completely empty it's tank out, which makes the pressure drop down to 0 and switches off all the heating and hot water... oh and the issue of all the water in the bucket! I'm honestly stumped. I wonder if I'm actually going crazy!

 

[Glen10]

So the point where it's leaking seems to be at the bottom where the pipe turns into the boiler. It's the return pipe from the CH. Is there a valve there? Is there a chance that occasionaly the valve get's stuck and causes the leak? But most of the time it shuts properly and there isn't any issue? Would that cause water to come out?

 

[jtsplumbing]

All you can do is keep an eye on it and you may find where it's leaking from, make sure all joints have been dried off and then check every day. Only valve on return is service/isolation valve that may drip but a bucket of water ?? have you tried adding extra pressure to see if that shows up the leak,

 

[Glen10]

Hi, Yes I've tried adding extra pressure. Put it all the way up to 2 bars... and nothing. When I saw it leaking it was only a couple of drops. But then it stopped. So maybe it turned into a couple of drops over 3 weeks when I wasn't looking. On the user manual and instalation instructions, it shows that it's leaking right at the point when it's called CH flow valve. Which I guess is the isolation valve. I assume that's much cheaper to replace than the diverter valve. Thank you