How to mend Vaillant 837 R1 Eco Tec

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

how do I rectify the fault as detailed below?

how do I vent the heat exchanger?

my boiler will no work?

Vaillant ecotec 831 plus?

Vaillant Thermocompact Fault?

Hot water comes and goes!?

Vaillant ecotec plus 630?

Valiant thermostat , BMU-Err ?

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

vaillant ecoTEC plus boiler fault code - how to fix?

Vaillant condensing boiler ecoTEC plus?

No hot water, intermittent when air temp drops?

Boiler over pressure on the hot-water side?

Vailliant turbo max plus 824e?

Vaillant Ecotech Plus 831 F22 fault?

Advice?

Vaillant ecomax 828/2 e water pressure sensor?

Vaillant vcw gb242 eh central heating problem?

Why is heating on at night?

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

Vaillant F22 fault?

Problem with the pressure in combi boiler?

What does f.25 mean?

Vaillant eco plus 531 boiler?

Valliant Eco tec 28?

Vaillant igniting issue ( domestic ) not CH?

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

my vaillant boiler is saying a code com on it ?

Vaillant 828E - no hot water?