Worcester Bosch Highflow 400 - HW de-pressurises CH

[ESDavey]

CH off and HW off. Run the HW tap and the pressure in the CH drops.

I have a 2nd problem where the CH is drawing in air to the system.

I'm guessing their could be a heat exchanger problem & plan to replace heatexchanged & seals. I'm also suspecting the diverter valve.

Any thoughts ? What is replaced in a standard service ? The boiler is 8 years old.

 

[superdupergasman]

I have had this boiler do this very thing which is most unusual as the
pressure usually rises when there is a pinhole in the DHW HE!

What I would suggest is that you get worcester out on a fixed price call out to replace this heat exchanger... it is a swine to replace!! They will fix all the faults at the same time!!!

Last time I did it I got the full DHW HW ready assembled with the manifolds and it still took me 6 hrs as I got a leak after I had rebuilt it!

Make sure the top can come fully off the boiler so you can get good access.

The second problem with the air could be anything...you may have a small leak somewhere allowing air to be sucked in but I would reserve judgment until you have had the DHW HE done.... I would also not be changing the diverter valve if there is no problem with the CH working.

 

[ESDavey]

Good advice - thanks !!

I have also thought about replacing the whole boiler for a Highflow 440 or 550 but I will ask Worcester to look at the current on 1st.

 

[Agile]

Before you get too involved I hope you have not left the filling valve open and either have no non return valve or one that is jammed open!

Tony

 

[ESDavey]

Agile, good thought but I have become very used to re-pressurising the system lately !

Something has failed inorder for the HW and CH to interact. Heat exchanger is my only thought.

Local plumber suggests that Combi boilers have a life expectancy of 10years approx. Is that right ?

 

[Agile]

Local plumber suggests that Combi boilers have a life expectancy of 10years approx. Is that right ?

Evidently someone short of work installing new boilers with little skill at repairing them.

I often repair old Vaillant combi boilers that are 20 years old!

Tony