Error S.22

Safety precautions:

1. If you smell gas, leave the property immediately and call the gas emergency number—do not attempt any checks. 2. Turn off the boiler at the mains before touching any external components. 3. Do not open the boiler casing, attempt gas work, or carry out electrical repairs yourself—these must be done by a Gas Safe registered engineer.

Initial homeowner checks you can safely do:

1. Look at the boiler display and note whether S.22 is the only code. If there are additional F-codes, write them down or photograph the screen. 2. Listen: can you hear the pump running continuously or intermittently? 3. Check the system pressure on the gauge/display—it should normally be around 1.0–1.5 bar for most systems. 4. Check thermostats, room controls and hot-water taps to confirm whether the boiler is being asked to run. 5. Check that the filling loop is closed and there is no visible leak on pipework or radiators.

Basic diagnostic and simple fixes you can try (safe, non-invasive):

1. If you recently topped up pressure or the boiler is purging: wait 10–20 minutes. The pump may run to purge air and then stop when the boiler finishes its automated cycle. 2. Reset the boiler once using the normal reset procedure in your manual; note whether S.22 clears and whether any other code appears. 3. If pressure is low (below ~1.0 bar): repressurise the system using the filling loop to ~1.0–1.5 bar following Vaillant guidance, then observe. Do not over-pressurise. 4. Bleed radiators to remove trapped air—airlocks can cause prolonged pump operation. After bleeding, re-check pressure and top up if needed. 5. Power-cycle the boiler: switch off at the mains for a minute, then switch on and observe whether the pump still runs continually. 6. If you hear loud or grinding noises from the pump, or the pump runs when there is no demand for heating or hot water, this suggests a mechanical or control fault.

When to call a professional and what to tell them:

1. Call a Gas Safe engineer if S.22 persists after the simple checks above, if there are additional fault (F) codes, if the pump runs continuously, if pressure repeatedly drops, or if you have no heating/hot water. 2. Tell the engineer: the exact code(s) displayed, when S.22 first appeared, what you did (reset, repressurised, bled radiators), the boiler pressure before/after, and any noises or leaks you observed. 3. Possible professional checks: pump electrical supply and wiring, pump impeller condition and seals, pressure sensor and wiring, diverter valve operation, blockage/airlocks in pipework, and PCB diagnostics.

Important notes:

1. Do not attempt to dismantle the pump, boiler internals, gas valve or PCB yourself. 2. Continuous pump operation is generally not an immediate gas safety hazard but will cause wear and may indicate a developing fault—arrange engineer attendance if it doesn’t clear quickly. 3. If in doubt, or if safety-related symptoms appear (gas smell, leak, major pressure loss, no pilot/ignition and additional fault codes), isolate the boiler and call a Gas Safe engineer.