Descale Mega flow unvented system

[Mark Godfrey]

Hi

I have an unvented Megaflow system, which is 10 years old. Since October last year we have had low pressure in the shower, I have had to take off the shower mixing valve every few weeks and clean out what I believe to be scale from the hot water inlet mesh (see photo attached) . The pressure then returns to normal.

The TPRV valve is slowly dripping in the tundish, even after i reset the airgap via the instructions on the front of the megaflow, could this be causing the buildup?

We have no problem with heating the water or running out for showers baths etc (4 of us in the house)

A new megaflow cylinder direct replacement is 2K + vat

Is it possible to descale the cylinder? Or could the solid on the mesh be something else?

Thanks
Mark

 

[ShaunCorbs]

That’s not scale it’s the internal baffle breaking down it is a know issue

 

[Mark Godfrey]

That’s not scale it’s the internal baffle breaking down it is a know issue

Is this fixable? And if not do you know if MagaFlow warranty would cover?

 

[ShaunCorbs]

Is this fixable? And if not do you know if MagaFlow warranty would cover?

New cylinder and you can try but good luck

 

[Chuck]

Keep a photograph record and the bits you fish out of the strainer as 'evidence'. I think there's a good chance you will be able to get Baxi (reluctantly) to fit an external EV and outlet strainer under warranty but they will probably refuse to replace the whole cylinder. I used to be a fan of Megaflo's (because they used high spec SS and were good at welding) but their reluctance to deal with this, and other, manufacturing issues under warranty in recent years has put them on my 'naughty list'.

Check the actual wording of the warranty that came with the cylinder. On one occasion, a Baxi rep tried to tell me that it was a lot more limited than it really was. If it comes to an argument, remind them that the small claims court will normally interpret ambiguities in your favour.

 

[Frelon]

....and think about installing a water softener! A lot less expensive than a replacement Megaflow - which you may have to buy anyway!

 

[Mark Godfrey]

Hi, it looks like they already fitted an expansion vessel (see attached)? This was like this on install, we were the first owners of the new build. Does this change things? I.e. do I still need a new cylinder?

Thanks
Mark

 

[ShaunCorbs]

That’s the heating expansion vessel

 

[Brian Woolley]

Same issues, but as an unvented qualified engineer, I removed the T&P relief valve and used an endoscope into the cylinder; finding the internal baffle plate badly disintegrated.
Contacted Baxi, who stated I’d require to pay a diagnostic fee for a representative to confirm my findings. When he visited, I showed him the baffle debris removed from pipes/shower valve filters/fully completed Benchmark logbook.
Soon afterwards, I received a callback from Baxi, confirming my request for a warranty replacement, which I would be responsible for fitment.
More than happy with the outcome, but prime importance of regular maintenance of the inline filter and depressurisation of the air gap.
My original MegaFlo was approximately 16 years old at time of warranty failure and replacement.

 

[Brian Woolley]

Photo of the hot water discharge pipe and minimal remains of the baffle.