Error 202

Safety precautions:

1. If you smell gas, leave the property immediately and call the gas emergency number — do not operate electrical switches or the boiler.

2. Do not remove covers, tamper with gas valves, igniters, the PCB, or internal components. Work on gas appliances must be carried out by a Gas Safe registered engineer.

3. Only perform visual checks and basic user-level actions (thermostat, reset button, pressure gauge). Keep children and pets away from the boiler area while checking.

Initial homeowner checks you can safely do:

1. Verify there is an actual heat demand: raise the room thermostat set temperature well above the room temperature or turn on the heating via the programmer/central control and watch the boiler display to confirm a call for heat is active.

2. Check hot water mode/priority — some boilers delay CH when DHW is running or vice versa.

3. Check boiler display for any other codes in addition to 202. If other fault/lockout codes are present, note them for the engineer.

4. Check system water pressure on the boiler gauge. Typical cold pressure should be around 1–1.5 bar. Re-pressurise only if you know how and the manual allows it; if unsure, wait for an engineer.

5. Check that wireless thermostat batteries are OK and that any wired external switching contacts are connected and closed.

6. Look at the condensate discharge externally in cold weather for frozen condensate pipe (if applicable) — a blocked/frozen condensate will usually give a different fault but is worth checking in winter.

Specific diagnostic and simple fix steps to try safely:

1. Confirm thermostat/programmer call: increase thermostat by several degrees or force heating on via the programmer. Observe whether the boiler moves from 202 to a pre-ignition status (often shown by messages like preparing for burner start or codes such as 283/270/200). If it does, the boiler is operating normally and just waited a short time.

2. Wait a few minutes. Anti-cycle protection can delay burner starts for a short period to prevent rapid on/off cycling. If the boiler starts after a short wait, no further action is needed.

3. Try a single reset of the boiler using the control panel reset button if the boiler will not respond to a legitimate demand. Wait at least 30 seconds before restarting. Do not perform repeated resets more than once or twice — persistent faults need an engineer.

4. If the boiler does not start, check for other displayed warnings or codes and the pressure gauge again. If pressure is low (well below 1 bar), top up the system following the manufacturer’s instructions, then try a demand again.

5. Check external controls: if you have a separate room thermostat, smart thermostat or an external on/off contact (programmer, relay), ensure it is showing a call for heat and that wiring/communications are intact. For wireless controls, check the thermostat is paired and batteries are good. For wired controls, ensure the HW/CH switching wires are secure at both the boiler and the thermostat/receiver.

6. Note any behaviour: does the boiler try to start (fan/pump run) then stop, or does it stay in the waiting state with no fan/pump activity? If the boiler attempts to start and then fails, or other fault codes appear, this points to ignition, gas valve, fan, sensor or PCB issues and requires an engineer.

When to call a professional and what to tell them:

1. Call a Gas Safe registered engineer if the boiler stays on 202 despite a confirmed heating demand, if additional fault or blocking codes appear, if you cannot restore normal operation after the safe checks above, or if you are unsure how to top up pressure safely.

2. When you call, provide: boiler model (Worcester Bosch GB162), the exact error code (202) plus any other codes or indicators shown, what actions you have already taken (reset, pressure check, thermostat checks), when the problem started and whether it is intermittent or continuous.

3. Ask the engineer to check the external control wiring/thermostat communication, anti-cycle settings, flow and return temperature sensors, and the boiler control/burner start sequence. Do not attempt repairs on gas or electrical components yourself.

Final note: Error 202 is often normal anti-cycle behaviour and not an immediate safety fault. Persistent refusal to fire when there is a confirmed demand needs a qualified Gas Safe engineer to diagnose and repair.