Baxi 105e pressure drops

Hi guys,

I found this forum searching for answers on pressure drops, think the expansion vessel has gone as well as PRV.

Been up in loft checked pressure after heating has been on for an hour and its gone upto 2.5 bar from 1 bar t could be re-pressurised maybe.

Then tried turning hot water on as well and the pressure went upto 3 bar then back down to 2.5 didn't notice PRV kicking in !

I read that these boilers are instant ones so you can't readily install an external vessel as there are 2 pipes going to the vessel one for heat and one for the water expansion !

Is this the case ? Thanks

I have noticed a drip for sometime now from under boiler which is in loft but not a lot it drys up its that little also noticed the outside pipe drips at times so lead me to the PRV and from the picture its fubar.

Took front of the boiler to take pics and about 6 months ago I put Leak Sealer F4 Express through filling loop to see if it was a leak on the heating pipeworks!

So how big a job is it to replace this I read another thread that said you need a boiler/gas engineer to do this ?

stevestomp said:

So how big a job is it to replace this I read another thread that said you need a boiler/gas engineer to do this ?

Click to expand...

crack on ...

Changing the EV is a pig on this boiler, Its quite simply boiler off the wall.
Needless to say only an GR engineer should deal with it.

Your choices are either replace the faulty vessel, which can usually be done if you have about 18" above the boiler, but this will most likely involve removing the flue, which could damage it. Unless it's installed with silicone! If it's a vertical flue, then it can stay put.

Other wise just diy bodge an external vessel into the filling loop connection, between the jig and the non return valve. As long as the vessel isn't leaking externally.

If the boiler is a 105e instant, I would honestly say you need to weight up whether it's worth pi***ng around with. They are notorious for failure and leaking, esp at that age.

Cheers for replies, have not got 18" above boiler so would go with external vessel and get the PRV replaced as don't need the expense of a new boiler, know a couple of plumbers who are gas safe guys !

I would rather lock horns with a Baxi 105 than mess about with some WB and Ariston leakers. iMHO, Baxi is a joy to work with. Have several components for possible one visit repair

Oh agree, Baxi are great to work on, we did their warranty work non stop for 4 years. But the instant just proved to be too unreliable, and age hasn't improved things
I'd hate to be a WB warranty engineer, ouch!

I doubt the ex vessel has split I suspect a recharge and prv change would sort it