Vaillant pro 28 intermittent hw problem

[g60rge]

new style vaillant pro 28

heating on,
open tap,
tap symbol flashes,
displays 0 degrees temp next to the tap symbol
tries to ignite continuously, programmer goes blank then comes back on each time

i tried it without the programer plugged in and the problem remains

if i turn the heating off and try hw on its own it works

vaillant said change the pcb £220 lighter and the problem still remains..

it was all working fine until i got home and the tennants called me

fuming....

any ideas?

i have a spare pcb if anyone needs one

 

[kozak1968]

Is it not under warranty?

 

[g60rge]

mate i wish it was, i asked the landlord already he just wanted me to fix it
im involved now so need to sort it!

 

[IDCHAPPY]

It's no fault I've ever seen on them, I'd have guessed pcb too TBH.
So it's not switching over from heating to hot water?

 

[g60rge]

no, but on the odd occasion even with just hw selected it will do it

annoying because it doesnt do it long enough for me to realise exactly what the boiler is doing, should have left it to keep doing it instead of pressing buttons lol

 

[stevetheplumber]

get the fault codes up?

 

[Masood]

mate i wish it was, i asked the landlord already he just wanted me to fix it
im involved now so need to sort it!

Sounds like it might not have been registered?

 

[g60rge]

it doesnt lock out so no fault code

 

[g60rge]

get the fault codes up?

wouldnt be surprised, looked like a bodge it and leg it installation

 

[Ermintrude]

Move thread any one? It's in the pubic domain

 

[bigads28]

Those display modules can do funny things to the boiler, you won'y know unless you try one though sadly.

 

[g60rge]

i was thinking it had something to do with the diverter sticking. hmm il have to give them a call once im back there tomorrow, i spoke to two different people today and they both sounded a bit miffed and said swap the pcb, so not holding much hope for anything further than that..

 

[jtsplumbing]

Some times its better to call out boiler manufacture on a fixed price, Had it a few weeks back with my own boiler, mystery fault, out they came and just kept replacing parts over £500 worth went in (Fan/PCB/Diverter motor/ electrodes ) cost me £260

 

[AWheating]

Call the manufacturer out for yourself and add yourself a percentage and give the landlord the bill.

 

[Leo21]

Some times its better to call out boiler manufacture on a fixed price, Had it a few weeks back with my own boiler, mystery fault, out they came and just kept replacing parts over £500 worth went in (Fan/PCB/Diverter motor/ electrodes ) cost me £260

What he said, sometimes your beaten.

 

[g60rge]

so vaillant have no idea, one even suggested the dreaded thermal fuse, i cut my losses on the pcb (good customer) and got the landlord to call vaillant for a fixed price repair

 

[IDCHAPPY]

It's for the best sometimes dude 🙂

 

[g60rge]

i have a feeling its due to the system not being flushed i got the tennant to message me when the problem re occurs and tell me the s numbers while its giving the problem

s.31 central heating thermostat knob turned off or no heat demand from by the ebus control unit - its set to max
s.97 water pressure sensor check is running demand dhw or ch is blocked - all valves are open for the record

must be something floating around in there

vaillants problem now

 

[moogwai]

ive had that problem before, vaillant tech told it was summat to do with the display thing not being plugged properly in the board. I worked ok when the flap was in the down postion but as soon as I lifted flap back up it would conk out again... I replaced the display unit and pcb...I do insurance work so cost wasn't an issue.

 

[moogwai]

.

......just remembered..... It wasn't a pcb fault....let was the low water pressure switch was faulty drawing the power from the board!! Replaced it and it was fine!