Glowworm Flexicom 30cx F9 fault code

Glowworm Flexicom 30cx F9 fault code

This is a clip of a Glowworm Flexicom 30cx Combi boiler with an F9 fault code.

On these Glowworm Flexicom boilers if you see an F9 fault code(alternates between F and 9), it means that the printed circuit board hasn’t detected the pump running sufficiently to continue operating safely and has shut down as a safety precaution.

On these boilers there is a pressure sensor which sits upstream of the pump which does two jobs;

First it determines if there is enough pressure in the boiler to work.

Secondly it looks for a little rise in pressure when the pump runs, which is how it knows if the pump is running or not.

If you have an issue with the pressure sensor or the fault you’re likely to see and F9 fault code.

Glowworm Flexicom cx combi boiler F9 fault with noisy failing pump

Below is a clip of a Glowworm Flexicom cx Combi boiler with a failing pump, causing an intermittent F9 fault code.

It’s always worth checking that you have sufficient pressure in your boiler before calling anyone out to have a look at it.

If your pressure sensor isn’t reading accurately it may think there’s more pressure in the boiler than there actually is.

For example the sensor may think there’s 1.0 bars worth of pressure when it’s actually zero.

As such the boiler will try to work but if there’s not enough water in the boiler the pressure sensor won’t get the little raise in pressure its looking for and you will see the F9 code.

The F9 fault code can affect any Glowworm Flexicom Combi boiler(24cx, 30cx and 35cx), and any Flexicom sx system boiler(18sx, 30sx).

The Glowworm Flexicom range of boilers are essentially derivatives of Vaillant boilers, some of the parts and faults are the same.

The F75 or F.75 fault is the Vaillant equivalent of the F9 fault code on the Glowworm Flexicom range, and we do have a page that talks about the F75 fault code in a bit more details