Vokera Linea Max 04 error when hot water too fast

[Huddersfield]

Hi all,

(Boiler = linear max - it's a big floor standing one and has been serviced recently and at all other times works perfectly. Pressure always shows ~1.5)

I've searched through my manual and fault finding guide but cannot find a solution to the problem I have:

Hot water and C/h work ok except when hot water is run from one of the bath taps. If the bath taps are turned on full the boiler shows an error code 04.

Code 04 = Insufficient water pressure or poor flow in the system.

When the bath tap is shut and opened at a steadier flow hotwater is delivered.

I'm guessing my bath taps are piped in 22mm hence the problem being unique to them.

So what does "poor flow in the system" mean?

Anyone know what I can check.

Many thanks for any tips.

John

 

[nickso]

check the flow switch and diaphragm, lower left side, near pump.

 

[Andygasman2010]

04 just means overheat doesn't it? Don't think this boiler has a primary flow switch.

I'd go with a blocked plate heat ex.

 

[nickso]

they do have a flowswitch. later ones may have a pressure switch but i don't remember ever seeing one.