Medium Warning
4.14 on Ideal Vogue Gen2

Your boiler is providing hot water to your taps correctly, but there is a communication or mechanical fault preventing it from heating your radiators.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

No CH But Cylinder Temperature Ok

What causes this fault?

This fault occurs when the boiler's internal components fail to switch the flow of heated water from your taps to your central heating system. The most common reason is that the diverter valve, which acts as a motorized gate, has become stuck or the motor driving it has failed. This means while the boiler is burning gas successfully, the heat cannot physically reach your radiators.

This issue is frequently seen at the start of autumn when the heating is turned on for the first time after being inactive all summer, which can cause internal moving parts to seize.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
Search the official register →

Related fault codes

4.12View →

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Radiators cold at the bottom

Sludge build-up — needs flushing, not bleeding.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →