Error 102

Safety precautions:

1. Before doing anything, turn the boiler off at the power switch and, if you can safely do so, isolate electrical supply at the consumer unit. Do not attempt any internal repairs while the boiler is live.

2. Do NOT attempt gas valve, burner or internal component repairs unless you are a Gas Safe registered engineer. If you have any doubt, stop and call a professional.

3. Keep children and pets away from the boiler while you inspect it. Avoid touching hot surfaces or hot pipes.

Initial homeowner checks you can do (safe, no internal access required):

1. Note the exact fault code and any accompanying messages or lights on the display. Record whether the fault is steady or intermittent.

2. Try a single reset using the boiler reset button. Wait for the boiler to restart and observe whether the 102 error returns. Do not repeatedly reset more than 2–3 times; repeated resets may lock the boiler out.

3. Check the boiler pressure gauge (usually on the front of the boiler): normal cold-system pressure is typically about 1–1.5 bar. If the gauge shows very low (<0.5 bar) or very high (>2.5–3 bar) pressure, note this value. If it is low, you can top the system up using the filling loop per the manufacturer’s instructions. If you are not confident, leave this for an engineer.

4. Inspect visible pipework, valves and radiators for any obvious leaks or recently damp areas that could cause pressure loss. If you find a leak, isolate water and call an engineer.

5. Bleed one or two radiators to remove air if you suspect airlocks are causing odd pressure behaviour. Recheck the pressure gauge and top up if needed.

Specific diagnostic steps (some are for a qualified engineer; homeowner actions limited to visual checks):

1. If the pressure gauge reads normal but the boiler still shows 102, it strongly suggests a faulty pressure sensor, its connector, or wiring rather than actual system pressure. Record the discrepancy to tell the engineer.

2. If the 102 fault appears after plumbing work, system bleeding or power interruptions, mention this to the engineer—wiring or connector disturbance is a common cause.

3. If you are a competent DIYer and the pressure sensor is externally accessible WITHOUT removing sealed covers, you may inspect the sensor wiring for loose or corroded connectors. Only perform visual checks; do not probe live terminals or remove components unless qualified.

4. For an engineer: measure the sensor output with a multimeter (voltage/current as specified by the boiler manual), check continuity and earth, compare the gauge reading to the transducer reading, and inspect the connector and harness for water ingress or damage. If the sensor is out of specification replace the pressure transducer with the correct OEM part.

5. The engineer should also check the PCB for faults, verify system pressure hydraulically (pump, valves, pressure relief), and check for airlocks or obstruction in the hydraulic block that could affect sensor readings. After replacement or repair, run the boiler through several heating cycles and confirm stable pressure reporting.

When to call a professional:

1. Call a Gas Safe qualified heating engineer if the 102 error persists after the basic checks, if the pressure is out of range and you cannot safely stabilise it, if you find a leak, or if any internal component needs inspection or replacement.

2. Tell the engineer the exact fault code (102), what the pressure gauge reads, whether reset cleared the fault and any recent work or events (power cut, plumbing work, freezing temperatures). This saves diagnostic time.

Final notes:

1. Do not attempt electrical or gas repairs yourself. Pressure sensor replacement and electrical diagnostics are best left to a qualified engineer.

2. Regular annual servicing reduces the chance of sensor failures and other faults. If the fault recurs after repair, insist the engineer checks wiring, sensor mounting and the boiler control board for any intermittent faults.