Viessmann Vitodens 222-F B2TH-32 Fault codes & diagnostics

12 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

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11 High 1 Medium
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Fault codes

All 12 documented codes

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A.11

The boiler has noticed the water pressure in your heating system has moved outside its normal range, which is usually a sign that water needs topping up or there is a small leak somewhere.

Medium DIY-safe £90-250

What to check first

  1. Make sure the boiler is switched off and has cooled down, then look at the pressure gauge on the front of the boiler. A normal reading is roughly 1.0 to 1.5 bar when the system is cold.
  2. If the reading is below about 1.0 bar, use the filling loop (usually a flexible silver hose under the boiler with two small levers or taps) to slowly add water until the gauge reads around 1.5 bar. Close both ends of the filling loop tightly afterwards.
  3. Switch the boiler back on and check the gauge again after a day or two. If the pressure keeps dropping, or the warning returns, check for damp patches or drips around the boiler and pipes and contact a Gas Safe registered engineer.

Parts commonly replaced

  • Expansion vessel
  • Pressure relief valve
  • Filling loop
  • Pressure sensor

Related codes

Full explanation for A.11
F.59

The boiler's exhaust fan isn't starting when it should, so it can't safely run the heating or hot water, and it needs a qualified engineer to check the wiring and fan.

High Engineer only £100-350

What to check first

  1. Check the boiler is switched on at the wall and that the power isn't affected by a tripped fuse or RCD in the fuse box.
  2. Make sure the boiler's external flue and vent terminal outside are not blocked by leaves, snow, debris or nesting material.
  3. Wait about 10 minutes, then press the reset button on the boiler control panel once. If the code returns, stop and call a Gas Safe registered engineer.

Parts commonly replaced

  • Fan assembly
  • Fan connection cable
  • Fan power supply cable
  • Control PCB (if the fan signal or power circuit has failed)

Related codes

Full explanation for F.59
F.62

Your boiler has stopped because its automatic check of the gas and air mixture failed, which usually means it is not able to release its heat properly, so it has switched off to stay safe.

High Engineer only £150-400

What to check first

  1. Check the pressure gauge on the front of the boiler with the system cold. If it reads below 1 bar, top it up using the filling loop, then close the loop valves again.
  2. Make sure the gas supply tap to the boiler is fully on and the boiler is switched on at the mains.
  3. Press the reset button on the boiler once and wait about 10 minutes to see if it restarts.
  4. If the fault code returns or the boiler will not restart, stop and call a Gas Safe registered engineer. Do not open the boiler casing or try to adjust the gas or fan settings yourself.

Parts commonly replaced

  • Gas valve
  • Fan assembly
  • Combustion controller
  • Ignition electrode
  • Heat exchanger

Related codes

Full explanation for F.62
F.346

Your boiler's automatic burner settings check has failed, so it has likely stopped to stay safe, and a qualified engineer should look at it.

High Engineer only £150-350

What to check first

  1. Check the boiler display and pressure gauge. Make sure the pressure is between 1 and 2 bar, and top it up with the filling loop only if it is below 1 bar.
  2. Check that the flue terminal outside the property is clear of leaves, nests, snow or other obstructions.
  3. Turn the boiler off at the switch, wait 5 minutes, then turn it back on and press the reset button once.
  4. If the fault clears and the boiler runs normally, keep an eye on it. If F.346 returns, stop resetting it and call a Gas Safe registered engineer.

Parts commonly replaced

  • Ionisation electrode
  • Burner gauze assembly gasket
  • Flue gas recirculation seal
  • Burner gauze assembly

Related codes

Full explanation for F.346
F.357

Your boiler has shut itself down because it isn't receiving the gas supply it needs to start safely, so it can't currently provide heating or hot water.

High Engineer only £120-300

What to check first

  1. Check whether other gas appliances, such as the cooker or fire, are working. If they are not, the problem may be with the gas supply to your home rather than the boiler.
  2. Make sure the gas supply valve at your gas meter is fully open, and check that you have credit on a prepayment meter.
  3. Switch the boiler off at its on/off switch, wait 30 seconds, then switch it back on once. If it fails again, stop and call a Gas Safe registered engineer. If you ever smell gas, leave the property and call the National Gas Emergency number on 0800 111 999.

Parts commonly replaced

  • Gas valve (gas train)
  • Gas pressure switch
  • Gas filter

Related codes

Full explanation for F.357
F.359

Your boiler is trying to start up but isn't igniting its gas flame, so it has shut itself down to stay safe and isn't providing heating or hot water until it's checked.

High Engineer only £150-350

What to check first

  1. Check that the gas supply is on by confirming your gas hob or other gas appliances work, and that the boiler's gas isolation valve (usually under or beside the boiler) is open.
  2. Check the boiler pressure gauge is between about 1 and 1.5 bar, and top up using the filling loop only if the manual says to.
  3. Turn the boiler off at the power supply for 5 minutes, switch it back on, and press the reset button once. If the fault returns, stop and call a Gas Safe registered engineer.

Parts commonly replaced

  • Ignition electrode
  • Ignition module (ignition unit)
  • Gas valve
  • Ignition lead

Related codes

Full explanation for F.359
F.369

The boiler started trying to light but could not detect a flame, so it has stopped as a safety measure and will likely need a qualified engineer to check the flame sensing and gas supply before it can run again.

High Engineer only £100-220

What to check first

  1. Check that the gas supply is turned on at the meter and that other gas appliances, such as the hob, are working.
  2. Check the boiler pressure gauge and top up with the filling loop only if it reads below 1 bar, following the manual.
  3. Press the reset button once on the boiler. If the fault returns, stop and call a Gas Safe registered engineer. Do not open the gas line or repeatedly reset the boiler.

Parts commonly replaced

  • Ionisation electrode
  • Ignition electrode
  • Burner gauze assembly gasket
  • Burner gauze assembly

Related codes

Full explanation for F.369
F.373

Your boiler has stopped because it could not finish setting up its gas-burning controls, which usually means it is not getting rid of heat efficiently and needs a reset and a check by an engineer.

High DIY-safe £100-400

What to check first

  1. Check the boiler pressure gauge with the system cold. It should read between 1.0 and 1.5 bar. If it is low, top it up using the filling loop only if your manual says how to do so, and stop once the needle is in range.
  2. Make sure all radiator valves are open and bleed any radiators that are cold at the top. Check the flue outlet and air intake outside the house for obstructions such as leaves, nests or debris.
  3. Reset the boiler by pressing the reset button for about 3 seconds, or switch it off at the isolator or fused spur for 1 minute and switch it back on. Let it run for a few minutes to see if the fault returns. If it does, or the boiler will not reset, call a Gas Safe registered engineer and do not repeat the reset more than once or twice.

Parts commonly replaced

  • Combustion fan
  • Gas valve
  • Flue gas or combustion sensor
  • Heat exchanger (if scaled or blocked)

Related codes

Full explanation for F.373
F.377

Your boiler has run into a problem setting up how it burns gas safely, so it has stopped as a precaution and needs a qualified engineer to check it.

High Engineer only £120-250

What to check first

  1. Check the pressure gauge on the front of the boiler. It should read between 1.0 and 1.5 bar when cold. If it is low, follow the filling instructions in your user manual.
  2. Press the reset button once on the boiler control panel, or switch the boiler off at the mains for a few minutes and back on.
  3. Check outside that the flue terminal (the pipe or grille on an external wall) is not blocked by debris, leaves, or a bird's nest. Do not open the boiler casing or attempt any internal adjustment.
  4. If the fault returns or the boiler will not restart, turn it off and call a Gas Safe registered engineer.

Parts commonly replaced

  • Ionisation electrode
  • Burner gauze assembly
  • Burner gasket
  • Flue gas recirculation pipe seal

Related codes

Full explanation for F.377
F.380

Your boiler tried to switch on but could not detect a steady flame, so it has stopped for safety and is not currently providing heating or hot water.

High Engineer only £120-300

What to check first

  1. Check that the gas supply is on, including the meter and any isolation valve, and that you have credit if you use a prepayment meter.
  2. Check the boiler pressure gauge. It should read roughly 1 to 1.5 bar when cold. If it is very low, top it up only if you have been shown how to do so safely.
  3. Wait a few minutes, then reset the boiler once using the reset button or the control panel. If the fault returns or the boiler will not reset, stop and call a Gas Safe registered engineer.

Parts commonly replaced

  • Ionisation electrode
  • Burner gasket
  • Burner gauze assembly
  • Gas valve
  • Control PCB

Related codes

Full explanation for F.380
F.416

The boiler has detected that a part which checks the exhaust fumes is not sitting in the right place, so it has stopped or may stop working until a qualified engineer checks it.

High Engineer only £80-180

What to check first

  1. Press the reset button on the boiler once and wait a few minutes to see if the boiler restarts.
  2. Check that nothing is blocking the outside flue terminal, such as leaves, nests, or debris, without touching the inside of the boiler.
  3. If the fault returns or the boiler stays off, do not keep resetting it. Contact a Gas Safe registered engineer.

Parts commonly replaced

  • Flue gas temperature sensor
  • Flue sensor seal or gasket
  • Sensor retaining clip

Related codes

Full explanation for F.416
F.457

Your boiler's fan has not started when it was asked to, so the boiler has stopped and is not providing heating or hot water until it is checked.

High Engineer only £150-400

What to check first

  1. Check the boiler is switched on at its on/off switch and that the power supply (the fused spur or switch) is on.
  2. Check the display shows a water pressure between 1 and 2 bar, and top it up using the filling loop only if the manufacturer's instructions say you can.
  3. Press the reset button once, wait a few minutes, and see whether the boiler starts. If the code returns, stop and call a Gas Safe registered engineer, as the fan and its wiring must be checked inside the casing.

Parts commonly replaced

  • Fan assembly
  • Fan power and control cable harness
  • Main PCB (control board)

Related codes

Full explanation for F.457
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