Brand specialist
Vaillant fault code diagnostics across Somerset
Vaillant fault codes are precise, but the F.75 in particular (no pressure change on pump start) trips a lot of engineers. Nine times out of ten it's a tired PWM pump or a blocked flow sensor — not the diagnostic mystery it looks like.
For: Owners of a Vaillant ecoTEC or ecoFIT with a fault code
Which codes we see weekly
F.22 low water, F.28/F.29 ignition, F.75 pump-pressure sensor, F.62 gas valve response. We test the actual electronics, not just guess parts.
Included in a Vaillant call
- Live pressure and pump-current readings
- Gas valve response tested with combustion analyser
- Ignition electrodes and lead resistance measured
- PCB error history downloaded from the boiler
- Repair vs replace priced in writing
Frequently asked
- Do you carry Vaillant parts?
- PWM pump replacements, ignition leads, pressure sensors and expansion vessels — yes, on the van.
- How long is F.75 to fix?
- 60–90 minutes for a pump replacement; the diagnostic itself is quicker.
- Are ecoFIT worth repairing?
- Absolutely — parts are cheap, they're reliable overall, and a well-cared-for ecoFIT easily hits 15 years.
Book the diagnosis
Send us the F-code and we'll come prepared with the most likely part on the van.
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