Vaillant - F81 F91 no hot water

[chr!stian]

Hi,

My Vaillant boiler (eco tech plus) doesn't warm the water anymore.

This morning it flashed between F81/F91 faults.

When I put the heating on, that does work, the display shows s.97, then s.2, s.3, s.4, the flame and the radiators get how.

When I put the water on I get s.24, then s.26, flame goes off, then s.20, and no hot water.

In another Valiant fault discussion someone suggested it could be warm-start function, but I turned it off and on by turning the wheel left or right (and 'C' went off or on), but it made no difference.

Does anyone have any suggestions (other than call an engineer)?

 

[Terry lambert]

937 ?

 

[chr!stian]

Yes, sorry

 

[Terry lambert]

Most likely shift load pump, Non return valve

I wouldn't say it was a DIY job, you might want to go for fixed price repair from Vaillant

 

[chr!stian]

OK thanks