F.22
Vaillant F.22, Low water pressure, system below 0.5 bar
MEDIUMRepressurise to 1.5 bar via the filling loop. If it drops again within days, there's a leak, book a trace and repair.
Read our full Vaillant F.22 guide →Same-day repairs for every Vaillant model, ecoTEC, ecoFIT and older ranges, by Gas Safe engineers who work on Vaillant boilers every single day. Most faults diagnosed and fixed in one visit, with genuine or manufacturer-approved parts.
Average reply under 10 minutes. No obligation.
Call 020 3000 0000Vaillant builds some of the most reliable boilers in the UK, the ecoTEC plus is practically the default boiler of the London loft conversion. But every design has its patterns, and after thousands of Vaillant callouts across the capital as part of our wider London-wide boiler repair service, ours are predictable: pressure-related F22 lockouts (often a slow leak or a tired expansion vessel rather than the boiler itself), F28 and F29 ignition failures as electrodes age, and F75 pump or sensor faults on units that have run hard through a few London winters. Hard water plays a part too, limescale shortens the life of heat exchangers and sensors across the whole city, which is why an annual boiler service is worth the money.
The good news: Vaillant parts are plentiful and well-documented, which is why our first-visit fix rate on Vaillant boilers is one of the highest of any brand we service. Our engineers carry the common ecoTEC parts, electrodes, sensors, expansion vessel kits, diverter components, in the van.
Repressurise to 1.5 bar via the filling loop. If it drops again within days, there's a leak, book a trace and repair.
Read our full Vaillant F.22 guide →Check other gas appliances first. If they work, the fault is internal, electrodes, gas valve or PCB. Gas Safe engineer required.
Read our full Vaillant F.28 guide →Often gas supply or flue related. Don't keep resetting, book an engineer.
Check your meter and emergency control valve. Persisting F.54 needs an engineer, never investigate gas supply yourself.
A restart may clear it once. Recurring F.75 means the pump or sensor is on its way out, book before it becomes a breakdown.
Electronics or wiring fault around the gas valve. Engineer only.
Showing a different code? Call 020 3000 0000 and read it to us, we'll tell you what it means over the phone, free.
Full guides: Vaillant F22 explained · Vaillant F28 explained
If your Vaillant is over 12 years old and facing a major repair, we'll give you the honest repair-vs-replace numbers on site, see our new boiler installation options.
Fixed quote before work begins, 12-month workmanship guarantee, genuine or manufacturer-approved parts.
"F28 on a Sunday morning. Engineer arrived within the hour, new electrodes fitted from the van, running by lunch."
"F22 every week for a month. They found the actual leak under the floor instead of just topping up the pressure like the last company."
"F75 diagnosed over the phone from the code, correct part brought first visit. Exactly how it should work."
Vaillant-trained Gas Safe engineers across all 32 London boroughs, 24/7.