Geminox Boiler Repairs London

Is gas working at other appliances in your home? If not, check your meter and any prepayment credit.

Pressure should read around 1.0 to 1.5 bar when cold. If below 1 bar, you may need to repressurise using the filling loop.

Is the room thermostat set above current room temperature? Are the batteries working?

Is the heating scheduled to be on? Check the clock is set correctly.

Locate the reset button on your Geminox boiler. Press once and wait. If the fault returns, do not keep resetting. Call an engineer.

In cold weather, the external condensate pipe can freeze. Look for a white plastic pipe exiting through an outside wall. If frozen, pour warm water over it gently.

The boiler tried to light and never proved a flame within its safety time. This is the Geminox equivalent of an ignition lockout and the most common reason one stops. Check gas is on at other appliances, and in freezing weather check the external condensate pipe. Reset once. If 133 returns, call an engineer.

The burner lit normally, then lost the flame while running. Usually the ionisation electrode, gas supply pressure, or flue gas being drawn back into the air intake. Reset once, then call an engineer if it repeats.

The limiter has cut the boiler out because the heat exchanger reached an unsafe temperature. Almost always poor circulation: a failing pump, sludge, closed radiator valves, or a blocked exchanger. Do not keep resetting a limiter lockout. Call an engineer.

Specific to systems with underfloor heating. The limiter protecting the floor circuit has tripped, usually because flow temperature has run too high for the floor build up. Call an engineer.

Flue gas has gone past its permitted limit, which usually points at a scaled or sooted heat exchanger or poor heat transfer into the system. Call an engineer.

System pressure has dropped below the minimum. Top up through the filling loop to between 1.0 and 1.5 bar with the boiler cold. If it falls again within days there is a leak, a weeping pressure relief valve, or a failed expansion vessel. Call an engineer to find it.

The fan is not reaching the speed the boiler needs before it will light, so combustion cannot be proved safe. Call an engineer. Never remove the casing or work on a flue yourself.

An internal fault in the Siemens burner management unit, the boiler's main control. Reset once. If 151 returns, the control needs testing. Call an engineer.

The control's settings are wrong or incomplete for the boiler it is fitted to. Common after a control board swap or a part-finished commissioning. Call an engineer.

The boiler has been deliberately locked out at the control, not stopped by a fault. Often left that way after servicing. Worth calling us before assuming something has broken.

Not a fault. The boiler is telling you a service interval has been reached. It will keep running, but book the service. See boiler servicing London.

On systems with a hot water cylinder, the anti legionella cycle did not get the water hot enough. Worth attending to rather than ignoring. Call an engineer.

A sensor has been wired to a configurable input that has not been assigned a job, or the sensor has failed. A commissioning fault rather than a broken boiler. Call an engineer.

An add on module, typically controlling a mixed circuit or a cylinder, has a fault or has lost communication with the boiler. Call an engineer.

An external contact wired into the control has signalled a fault. What it means depends on what was wired to it at installation, so it needs someone who can read the commissioning settings. Call an engineer.

If the display is blank or the boiler simply is not firing with no number shown, check the room thermostat, the programmer and its batteries, and the fused spur. If those are all right, call us.

Code 133 is the one you are most likely to see on a Geminox. The boiler attempted to light and no flame was proved. Common causes include a gas supply problem, a worn or sooted ionisation electrode, or a blocked condensate pipe in winter. Check gas is on elsewhere in the home. Reset once. If the lockout returns, stop and call an engineer.

If your Geminox shows 323, system pressure has dropped below the minimum operating level. Top up via the filling loop to around 1.0 to 1.5 bar when cold. If pressure drops again within days, there may be a leak in the system or a failing expansion vessel. Call an engineer to find the cause.

If your Geminox shows 119, the heat exchanger limiter has tripped and the boiler has locked out for safety. This can indicate a circulation problem, pump failure, or a blocked heat exchanger. Do not keep resetting. Call an engineer to check the system.

On Geminox combi boilers, you may get heating but no hot water, or the reverse. This often points to a diverter valve issue. The diverter valve directs hot water between taps and radiators. When it wears or sticks, hot water delivery becomes unreliable. Call an engineer for diagnosis.