Hi...first post here hope you can help me,  My Baxi 105e will not switch from hot water over to C/H I have found the problem its the 3 way valve (Hydraulic outlet assembly).

what happens is the valve switches over to the hot water but when the tap is turned off it should then switch back to the C/H, but the pin which the switch pushes in is sticking. if i apply a small amount of pressure manually it switches over and the C/H starts working again, but when ever the hot water is run it sticks again.

My question is how easy is it to remove the pin and clean it and do I need to drain the system of the C/H to do it.  or is it best to remove the full assembly and strip and clean it all.  any parts internal I should be aware of while doing this .

hope I have made it clear any advise would be helpfull

This'll be the diverter valve.
One thing to check before you begin to dismantle the boiler.
Make sure the pump is running properly. If it isn't, the valve won't lift enough to make the switch mounted on top. I learnt this through bitter and expensive experience! The pump looked as if it was running ok, but it wasn't. I only discovered this after removing the valve and changing the diaphragm needlessly!!

If no joy and the pump is actually working ok........

Be careful with the rubber diaphragm when you take the valve apart after removing it from the boiler.
It is advisable to get a new replacement ready to fit in case you hole the diaphragm when pulling away from the valve body.
They're not expensive.

The valve is!

Check that the diaphragm you remove does not have any holes in it.
Also, clean the valve out thoroughly before refitting.
Make sure you flush the system completely with some good flushing chemical, then top up and add a good quality inhibitor.
If the valve is stuck because of heavy muck and debris, it's time to take the radiators off and flush out each in turn with a hosepipe.

TT
(Not a plumber, but someone who has 'been there' with the BAXI 105e!)

As Scruff doesn't seem to be on at the moment PM me your email address and I'll send you a copy