Baxi Duo-tec problems

[martyl]

Hello everyone. I have an issue with my Father's Baxi Duo-tec combi boiler which was installed in 2017.

The boiler hadn't been used for a few months. On first using the heating we had water dripping out of the bottom of the boiler so called a plumber. They found the Leak was coming from the top of the boiler as the condensate pipe was blocked. This was sorted.

After the plumber went we put the heating on again and water was still dripping out of the bottom of the boiler. Called plumber back to be told this time the leak was in the middle of the boiler as the expansion tank had failed and no pressure in system. Expansion tank and PRV was replaced.

Boiler now works but there is water coming out of the overflow pipe. The pressure gauge on the boiler is between 1-2 bar. There is no noise from the boiler and hot water and all rads heat up well. The boiler is not overheating and there are no error codes. Plumber is now telling me it's a blocked heat exchanger and a new boiler is needed. I'm finding this hard to believe.

Has anyone any ideas what could be wrong?

 

[BlueLoo]

The plumber.

 

[gas112]

your boiler should have 7 year warranty

 

[martyl]

Thanks. I don't think the boiler was serviced every year so I think the warranty is invalid now.

 

[CBW]

what exactly are you calling the overflow pipe?

 

[martyl]

The copper pipe that goes outside. I think it's where the prv feeds to.

 

[CBW]

The copper pipe that goes outside. I think it's where the prv feeds to.

Then I would say you have an expansion issue - could be the communication pipe is blocked, could be the new expansion vessel is flat, could be debris has got on the seat of the new prv.

 

[sugarlips]

when the boiler is cold, make a note where the pressure gauge is reading, leave a few hours or overnight, if pressure rises and you havnt had central heating on then the plate water exchanger is "passing" and you will need a new one, not an expensive repair.

 

[martyl]

The pressure remains at 1bar when cold and then rises to about 1.8bar when hot. The gauge is showing that the pressure is not going above 2 bar which is why I can't work out why the prv is letting water pass. The water only flows from the copper overflow pipe when the boiler is working e.g. heating is on.

 

[martyl]

Then I would say you have an expansion issue - could be the communication pipe is blocked, could be the new expansion vessel is flat, could be debris has got on the seat of the new prv.

Thank you. I have my usual plumber coming to have a look this week. Hopefully he can identify the issue and fix it without replacing the whole boiler but thank you for some areas to investigate.