How to mend Vaillant Exomax 824/2

how do I rectify the fault as detailed below?

Vaillant eco plus 531 boiler?

Valiant thermostat , BMU-Err ?

Vaillant vcw gb242 eh central heating problem?

my vaillant boiler is saying a code com on it ?

vaillant ecoTEC plus boiler fault code - how to fix?

Boiler over pressure on the hot-water side?

How do I fix f22 error on my Vaillent Ecotec Plus boiler?

What does f.25 mean?

Vaillant ecomax 828/2 e water pressure sensor?

Vaillant ecotec plus 630?

Vaillant Ecotech Plus 831 F22 fault?

Valliant Eco tec 28?

Problem with the pressure in combi boiler?

Vaillant condensing boiler ecoTEC plus?

Vaillant F22 fault?

Vaillant Thermocompact Fault?

Advice?

Vailliant turbo max plus 824e?

Vaillant igniting issue ( domestic ) not CH?

can i replace my Potterton EP2 2 way programmer with a Center EHE0200361 RF?

Hot water comes and goes!?

Why is heating on at night?

Vaillant 828E - no hot water?

Vaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?

how do I vent the heat exchanger?

my boiler will no work?

No hot water, intermittent when air temp drops?

Vaillant ecotec 831 plus?

how to fix water pressure its down at bottom of grey part?