I could see it was apparently coming from what I thought was a grub screw missing that holds the DHW Pressure Differential Valve to the Diverter Manifold. Replaced with a suitable set screw........ still a leak.......looked further and find another screw hole but no screw in it? But wet, suggesting it is coming from there. On installation/sevicing instructions diagram it only shows 2no. screws but 4no holes, so maybe there wasn't a screw missing, other than intentially. if that is the case why is there water leaking out of the empty holes? Baxi won't help me insisting I contact a Corgi Engineer.......who has already supposedly looked and didn't know where it was coming from!! The leak is not always apparent. Can anyone please advise I don't want to pay 20 quid for a tiny screw to be screwed in! Should there be four grub screws in etc. Thank you in advance for taking the time to read my query.

Compulsive DIYer!, January 2009

I have a leak coming from the pin on my diverter valve what can I do to stop it thanks

Darrell, July 2012

Hi Dan, with the DHW pressure diff. assembly removed---- according to manual instructions-----you look the diverter ass, square in the face. The part with the gub screws is actually a large nut, undoing the nut reveals a seal and spring ass. but as far as I know you cannot get a replacement for this ass, you have to buy the whole 3 way diverter valve. current price circa £99. The primary circuit has to be drained before working on the diverter valve. Refer to manual page 35-36.

Haitch

Haitch, April 2012

Changing a diverter valve on baxi 105e a straight forward job ?

dan, March 2012

i have a leak on my baxi 105e and theres little drips coming out now and then from where the grub screws go, theres 2 grubs screws in already, then the drips are coming out of one of the spare grub screw holes. any advise on what parts to get to solve the leak

gavin q, March 2011

Hi Must be common I have the same problem.I have yet to tackle it bought a diaphram kit for outer part of diverter valve having problems locating a kit for the actual three way valve but is it worth it I cannot believe the three way valve is not servicable anybody knows different please post and good luck to you all.I have tried contacting Baxi but so far no luck

Roger Partridge, February 2011

when i start the heating up water passing down the back of the boiler and then pressure loss.is the boiler kaput or could it be a seal or somethoing on rear.

ray scaddan, April 2009

Fixed it!

Had to change the three way diverter manifold £84 (ouch), they don't sell the innards for it so have to get a whole one. Was a bit fiddly as my boiler is in a cupboard but I managed it.

Definitely was the , leaking around the 'inner push pin', running really nicely now I have bled it all.

Good luck everyone else.

Neil from Rayleigh, February 2009

Exactly same issue/fault on my Baxi 105e Combi.

I can confirm is two screws on my 105e, threw me for a while that one!

I have also replaced both diaphragm kits presuming a split to be the cause of the leak and it now seems to be worse! Not to proud of myself there.

Leak is dripping from the join of the hot water Pressure Differential Valve and the the Diverter Manifold. Seems to emanate from within the diverter manifold itself.

Losing all pressure on the heating circuit so definitely coming from there. Must be some internal seal or 'gate' either corroded or not closing properly which is allowing the leak.

I am not a boiler engineer but I can't believe that joint is intended to be water tight? It seems to be a mechanical join intended to align the rods that push each other.
There is no compression seal or washers there, the parts simply engage and are secured by the two grub screws gripping the flange/collar of the join. Can't believe that was ever intended to be water tight?

If anyone knows the answer do post please. May need to call a plumber to this one, will post solution here if I crack it.

Neil - Rayleigh, February 2009

I'm in exactly the same boat. I have actually disassembled the diverter valve and reassembled it with sealants between joints which has reduced the leak from 1/2 a litre a day to a 1/8. inside the area that you refer to it is badly joined. where you would imagine that there would be a o ring or maybe a fibre washer there is not and two parts of brass press against each other,via the two grub screws. I'm going to research a better sealant and have another go. i'll let you know how I get on.

Damo the builder., January 2009

No, it comes with 2, not 4. Sounds like your diverter valve is leaking. Its difficult to tell whether its coming from the pressure differential or the diverter valve pin you see as you crnt actually see inside.

Joe, January 2009