Vaillant Turbomax plus 828e Hot water problem

[ShadesVFR]

My Turbomax is taking 2 minutes to go into high fire for the hot water.

Open a tap on high flow wait 2 minutes hear the gas valve click into high fire,and temperature rises to whatever I have the stat set at.

Why the delay in going to high fire ?

Green light flashes as soon as tap is opened and boiler fires at low rate. Any pre-warmed water then dissipates and temp drops to 40.

Could it be the PCB. Aqua sensor ok presumably due to seeing green demand light flashing on tap opening. Gas valve only doing what it is asked,therefore must be a problem with whatever is giving the gas valve its information ie PCB ?

 

[Dan Robinson]

Flashing light is indicating the warmstart feature is topping up.

Are you getting S.10 or S.20 when you open the tap?


Press the i button to find out.

 

[ShadesVFR]

I get S20 then S23 then S 24.

 

[Dan Robinson]

So the boiler thinks it is going warmstart rather than hot water.

 

[ShadesVFR]

Yes. Not getting S10 at all.

Just tried when water was at 60 degrees after warmstart. Waited a while after tap opened to change from S30 to S23 then pretty quickly S24.

Aqua sensor fault ?

 

[Dan Robinson]

It's looking that way.

 

[ShadesVFR]

Is it worth just changing the Hall sensor first ?

Or would you replace the whole unit ?

 

[Dan Robinson]

Can't say I ever had one of these fail on me so wouldn't know.

Perhaps one of the Bunnymen will advise

 

[Bunnyman]

194819 change the lot an be careful you get the clip back on the dhw ht exch right, they have a habit of jumping off an flooding everywhere