Baxi Combi

[TankEngine]

My Baxi Combi appears to be over-pressurising and the overflow pipe that leads to the outside has a constant drip, drip, drip; this dripping gets worse when the boiler is on and the hot water is being pumped round the CH circuit or the hot water tap is on.

It has been suggested to me that this might be the heat exchanger leaking internally - I recently replaced this part due to an external leak on it. Is there anything else that could be causing this?

Many thanks,

Jon

 

[gas4you]

Firstly check that your filling loop is fully off and not letting by.

The plate HE being holed could cause this but not the main HE.

Drain the boiler and check the expansion vessel. See FAQ's on how to do this.

 

[TankEngine]

Thanks Dave - I have read post 31 in FAQ about Pressure Problems. Am I right that if the PV needs repressurising, the pressure in the boiler should drop massively once the boiler cools? On mine, the pressure stays high and the boiler keeps dripping even when totally cold.

 

[Agile]

Remove the flexible filling hose and see if the filling valve is leaking.

Leave it off for a couple of days and see what the boiler pressure does.

Which Baxi model? They are not all the same! Just as a Ford Fiesta is not the same as a Ford Pilot !

Tony

 

[TankEngine]

Cheers - it is a 105e.

Jon

 

[Agile]

Now is that a 105e Instant?

 

[TankEngine]

Erm - I don't know. How can I tell?

 

[gas4you]

Has it got 'Pre-Heat' written on the HW stat dial?

 

[TankEngine]

No - nothing written on it, just a plain grey dial.

 

[gas4you]

Just a standard 105e then.

Check filling loop as suggested first.

 

[TankEngine]

OK will do - if this doesn't sort it, from my earlier post am I to take it that the PV is no longer thought to be at fault and that the plate HE could need replacing again?

Thanks for your help with this.

Jon

 

[gas4you]

You will need to test the EV before making any decisions.

Press the valve pin down on it and if water comes out it is knackered. If just air comes out then you will need to drain the EV and test the pressure in it, as the FAQ's instruct.

If all of this checks out then start looking elsewhere.

 

[TankEngine]

Pressed the valve on top down - water came out!!! Does this mean that a new EV is needed. Interestingly, there is also a piece of mortar or plaster wedged between the EV and the boiler. Could this have caused it to fail?

Thanks,

Jon

 

[gas4you]

Yes new EV time I'm afraid

Hope you've got a good couple of feet or more above the boiler, otherwise it's boiler off the wall time.

Unless you want to fit an unsightly external EV somewhere?

 

[TankEngine]

I'll remove the shelves above if I have to - does this mean I won't need to take the whole boiler off? Do you know what part number the EV is?

Thanks for this.

Jon