Boiler leaking from the heat exchanger, fixable?

robowen

It's been a while since I worked on boilers so plz if anyone can tell you for definite then rely on them.

I think you are referring to the Automatic Air vent. This allows air from the heat exchanger to escape. I'm not sure if you have to manually release the air in which case it wouldn't be automatic. Usually you'd open it for filling the heat exchanger.
Does it have a pipe coming up right through the case and the vent is a separate part ?
is it a soldered on part or nut and olive kind of fitting you can tighten up ?

Edit> In the manual it says it's screwed on.
Drain primary circuit first.
Unscrew vent from 'pump body' (I think that's wrong as it's the same instructions for the air vent on the pump body.)
Anyway, unscrew it from what it's screwed into.
Examine the O ring seal and replace if necessary. Replace air vent if necessary.
Reassemble in reverse order and refit the large grommet.
Ensure the grommet is sealed correctly to the top panel.

Edit> Manual. add the w's. potterton.co.uk/downloads/Potterton_Gold_Combi_HE_Install.pdf

Piece of p*** if you ask me. What's the worse that can happen ? you de pressured the system which it does anyway and you've take the vent off.

Alex1983

I’m not 100%, southcoast likes his baxi group boilers so he may know for definite, but I think the air vent sticking out the top is attached to a 8/10mm copper pipe with a nut and fibre washer and then the copper goes into the top of the heat exchanger with o ring and held in with a clip. I’d suspect the o ring has failed and it’ll be a cheap and easy repair.

southcoastrgi

aftonandpaul

Thanks all who have helped thus far. I'm hoping for a happy ending here, almost there.

So I'm willing to try this myself, and I think I'm right I'm saying I need to
1) isolate the boiler and drain it independently of the rest of the system
2) remove the part (diagram above, thanks South) replace the O ring
3) reassemble
4) refill the boiler with water

It's number 1 and 4 in not sure about. How can I drain and refill the boiler properly?

Thanks

aftonandpaul

Ok this is as far as I have got.

1) Isolate power supply to boiler
2) close heating return valve, heating outflow valve and mains inlet valve
3) ensure Auto air valve cap at top of boiler is open
4) attach hose to drain valve and run hose to suitable drain
5) open drain valve and allow water to flow out
6) gain access to the offending joint (have to unmount the spark box. Detach the condensate drain pipe from the White tray above the heat exchanger. Rotate the White tray anti clockwise 90 degrees.
7) remove Auto air valve and pipe from top of boiler.
8) inspect and replace O ring
9) replace arv and pipe.
10) replace White tray, condensate pipe, spark box
11) open main inlet valve
12) refill boiler using filling loop, ?how do I know when to stop? Will the arv seal up automatically and then I keep going till approx 1.5bar?? Do I need to do anything to the arv??
13) close filling loop
14) open heating valves
15) switch on and check for leaks and loss of pressure

See I'm putting some effort into research here 😋
How's that? Please correct if there's an error.

Thanks

aftonandpaul

All gone very quiet...:(

Alex1983

The thing is mate, I’m happy to help on here to diagnose problems so you don’t get ripped off by someone coming to repair it but you need to be gas safe registered to do what you want to do, there are tests that need to be carried out in the boiler once you’ve repaired it.

BorisThomson

robowen wrote: »

Piece of p*** if you ask me. What's the worse that can happen ? you de pressured the system which it does anyway and you've take the vent off.

What's the worse that can happen when randoms mess around with gas?

Crikey.

aftonandpaul

Correct me if I'm wrong but I'm not interfering with any gas circuits here, water only. Therefore should be fine to do this myself?

aftonandpaul

Ok so thanks to all those who gave *encouraging* comments on here. Through a combination of a lot of help from here and a little research of my own, the problem seems to be fixed.

Here's the problem, the offending O ring from the top auto air valve. Had lost its spring and gone hard, perhaps shrunk a little too. Water was leaking from the top of the heat exchanger where the ARV pipe entered. O ring about the size of a 20p, but cost £10.29. No, it wasn't made of platinum despite the price. !!!!!! rip off.

tinypic.com/r/zv33ox/9

All reassembled, boiler refilled, switched on, pressure seems stable at 1.5 bar. Prior to the repair, 1.5 bar = water steadily leaking. Post repair, seems dry so far.

Here's hoping it lasts. Thanks again.