Main E317 / 162 fault code explained

Main boiler fault code E317 / 162 means the appliance has detected the wrong electrical power-supply frequency, measured in hertz (Hz). Main’s current error-code table lists this meaning for the Main Eco Compact Combi and Main Eco Compact System ranges.

This is an electrical-supply and boiler-control issue, not a gas-pressure code or a heating-system water-pressure warning. Keep the boiler casing closed. Do not test mains electricity, open the fused spur or attempt work on the boiler’s wiring.

What does Main E317 / 162 mean?

The UK mains supply normally alternates at a set frequency. The boiler’s electronics expect the incoming supply to remain within the conditions for which the appliance was designed. Code E317, sometimes displayed as 162 depending on the control format, means the boiler has detected an electrical frequency that it considers incorrect.

The number on the display identifies the type of condition; it does not explain why it happened. An engineer may need to consider the boiler, its electrical supply and the circumstances in which the code appeared before deciding what repair is needed.

Which Main boilers use E317 or 162?

Main’s official error-code page groups this code with the Main Eco Compact Combi and System boilers. It also appears in a wider table covering several related Baxi and Potterton products, but model names and displays vary. Do not assume that every Main boiler uses E317 or that 162 always has the same meaning on an unrelated appliance.

Find the model on the front casing or in your paperwork without removing panels. When booking a repair, give the engineer the exact code and model. A clear photograph of the closed boiler and display can be helpful.

Is E317 the same as low voltage?

No. Main lists E317 / 162 as wrong electrical supply frequency. The nearby E385 / 165 code is listed as under-voltage. Frequency and voltage are different properties of the electricity supply, even though either type of problem can prevent the boiler from running normally.

This distinction matters because a generic description such as “power fault” can send a homeowner towards the wrong advice. Record the complete code rather than relying on a partially remembered number.

Why might the code appear?

The code can appear when the boiler electronics detect supply conditions outside their expected range. The display alone cannot show whether the condition came from the external supply, a temporary interruption, a generator or backup-power arrangement, or the appliance’s own control electronics. Those are possibilities to assess, not conclusions a homeowner should draw.

Make a note if the fault followed a power cut, electrical work, use of a temporary power source or a wider issue affecting neighbours. Do not connect the boiler to a generator, inverter or extension lead as an experiment. Its permanent electrical supply must be assessed safely.

What symptoms may accompany E317 / 162?

You might notice:

• the boiler display is on but heating and hot water have stopped;
• the code appeared after power was restored;
• the boiler attempts to start and then stops;
• the fault returns when demand begins; or
• other lights or appliances in the property behaved unusually at the same time.

These details help build a useful timeline, but they do not prove the location of the fault. A boiler can be the first appliance to report an electrical irregularity because its control system monitors its own operating conditions closely.

What can I safely check?

Limit your checks to simple observations:

• Write down whether the display shows E317, 162 or both.
• Check the visible model name and whether heating and hot water are both affected.
• See whether ordinary lights and appliances have power, without removing covers.
• Ask whether neighbours experienced a power interruption if that is easy and safe.
• Note any recent power cut, electrical work or use of backup power.

Do not remove the boiler casing, test sockets, probe the fused spur, inspect the consumer unit, alter wiring or measure frequency or voltage. These actions expose you to mains electricity and can interfere with safety-critical controls.

If the exact user manual allows one ordinary user reset, follow that published instruction once. Do not repeatedly reset a returning E317 / 162 code. Repeated attempts will not correct an unsuitable supply condition or a confirmed internal fault.

Should I call an electrician or a boiler engineer?

A Gas Safe registered boiler engineer is a sensible first contact when E317 / 162 is shown on the boiler. They can confirm the code, appliance model and whether the boiler itself needs repair. If evidence points to the property’s electrical installation or incoming supply, an appropriately qualified electrician or the local electricity network operator may also be required.

If several appliances are behaving abnormally, lights are flickering significantly, there is a burning smell, or the property has repeated electrical tripping, switch off affected equipment only if it is safe to do so and seek urgent electrical advice. Do not keep operating the boiler to see whether the problem clears.

What will the engineer consider?

The engineer can review the boiler’s fault history and model-specific service information, confirm the permanent supply arrangement and assess the boiler controls safely. Any electrical measurements, wiring checks or internal control-unit work require appropriate equipment and competence.

The aim is to separate an external supply problem from an appliance fault before parts are replaced. Once the cause is confirmed, the correct repair can be completed and the boiler’s operation checked.

What if I smell gas or suspect fumes?

E317 / 162 is an electrical-frequency code, but normal gas-safety rules still apply. If you smell gas or suspect a leak, do not use electrical switches or naked flames. Leave the property and call the National Gas Emergency Service on 0800 111 999 from a safe place. If a carbon-monoxide alarm sounds, leave immediately and follow the alarm manufacturer’s emergency instructions.

Book a fixed-price repair for Main E317 / 162

This code needs careful checks rather than DIY electrical testing. A fixed-price boiler repair gives you a clear price and an engineer visit focused on getting the Main boiler working safely again.