Overview
E160 on Potterton Promax Combi/System/Store boilers is a fan fault code. It means the boiler control has detected a problem with the flue/combustion fan or its related circuitry: the fan may not be running when it should, it may be running more slowly than expected, there may be a wiring or connector fault, or the control board may not be getting the correct feedback from the fan. Common root causes are a failed fan motor, a seized impeller, broken or loose electrical connections to the fan, a fault on the PCB or a blocked/obstructed flue causing the system to report a fan issue. Severity is medium to high. A faulty fan prevents safe removal of combustion gasses and will usually cause the boiler to lock out; the boiler should not be used continuously in that condition. If the fault is intermittent you may get repeated lockouts and unreliable heating/hot water. Some basic checks and a power-cycle/reset can be done by a homeowner, but most diagnostic and repair actions involve live electrical work and gas isolation and therefore require a Gas Safe registered engineer. Any physical work on the boiler’s combustion parts, gas connections or internal wiring must be carried out only by a suitably qualified engineer. If E160 appears, a simple reset may temporarily clear the code, but persistent or recurring E160 should be diagnosed and repaired by a professional. A qualified engineer will confirm whether the fan itself needs replacing, whether wiring or the PCB is at fault, and will perform the necessary safety and commissioning checks after repair.
Possible Cause: Fan fault
Troubleshooting Steps
Safety precautions:
1) If you are not a Gas Safe registered engineer do not attempt to remove combustion covers, disconnect gas fittings, or work on live mains wiring inside the boiler. Those tasks are hazardous and illegal for unqualified persons.
2) Before doing any visual checks switch the boiler off at the programmer and isolate the electrical supply at the fused spur or consumer unit. Do not work inside the boiler with power applied.
3) If you smell gas, evacuate the property, do not operate electrical switches, and call the gas emergency number immediately.
Initial homeowner checks you can safely do:
1) Check the boiler display and any fault history. Note whether E160 is steady or intermittent and whether other codes appeared simultaneously.
2) Try a simple reset: turn the boiler off at the programmer and at the boiler’s on/off switch, wait 30 seconds, then turn back on and observe. If the fault clears and does not return, monitor for recurrence.
3) Check the mains power supply to the boiler: ensure the fused spur or isolator hasn’t tripped and the house fuse box is OK.
4) Check the flue external terminal and air intake/ventilation are clear of leaves, bird nests, debris or snow which could cause airflow problems. Don’t attempt to push objects into the flue.
5) Listen when the boiler starts: do you hear the fan spin briefly before ignition/lockout? A complete absence of fan noise on start suggests the fan is not running.
6) Check system pressure is within the normal range (usually about 1–1.5 bar). Low pressure can cause unrelated faults; top up only if you know how to and the boiler instructions permit it.
Safe visual checks with power off (homeowner can do if comfortable):
1) Isolate power at the spur/consumer unit. Remove the outer casing only if you are comfortable doing so and the manufacturer manual permits access for homeowners. Many boilers require Gas Safe engineers to remove combustion covers — if in doubt do not remove.
2) With power isolated, visually inspect accessible wiring connectors to the fan for obvious loose connectors, burn marks or rodent damage. Do not pull on wires or attempt electrical repairs.
3) Check that the flue fan’s plastic ducting and grommets are intact and that no foreign object is visible. Do not try to spin the impeller by hand on a powered motor.
Diagnostic and fix steps (for Gas Safe registered engineer only):
1) Engineer isolates electrical supply, gas and water as per safe working procedures and follows manufacturer instructions and local regulations.
2) Confirm fault using service mode/logs. Measure supply to the fan when the boiler calls for pre-purge to check for correct mains/controlled voltage at the fan connector, and measure motor current/rotation. Verify fan tachometer/feedback signal if the fan has one.
3) Inspect fan impeller for seizing, debris or mechanical damage. Check bearings and motor windings for continuity and insulation.
4) Inspect and test wiring harness, connectors and earths between the fan and the PCB. Repair or replace any damaged cabling or terminals.
5) If fan motor is faulty, replace the fan assembly with the correct OEM replacement. Follow manufacturer procedure: isolate power/gas, remove front and combustion covers, undo relevant fixings, disconnect electrical connectors and sensor/sensing pipe, remove and replace fan assembly, ensure gaskets/grommets and injector position are correct, refit covers and seals as specified.
6) After replacement, engineer must restore supplies, carry out gas tightness tests, flue/spill testing, and verify correct combustion and safe operation. Run the boiler through full operating cycles and confirm no further E160 or related fault codes. Record service actions and any parts replaced.
When to call a professional:
Call a Gas Safe registered engineer if the fault persists after a reset, if you hear no fan noise at start, if you find damaged wiring or anything suspicious, or if you are asked to open the combustion casing by the manual. Only a qualified engineer should carry out electrical measurements on live circuits, disconnect or replace the fan, isolate and reconnect gas, or perform combustion and safety checks. Repeated E160 faults can indicate a failing fan, wiring/PCB issues or return problems from the flue that require professional diagnosis and repair.
Helpful Resources
Boiler Manual
Download the official PDF manual for the Potterton Promax Combi, System, and Store.