Medium
D.h.w. operation on Biasi Riva Compact 24S (M90E.24S)

Your boiler is currently providing hot water but ignoring heating demands, or it may have a sensor glitch causing it to stay in hot water mode.

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.

What the manual says

Manufacturer manual

Lamp 2 ON (or Lamp 4)

From this model's manual
Verified against the Biasi Riva Compact 24s installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check all hot water taps are fully turned offEnsure there are no dripping taps or leaking shower headsTry resetting the boiler by turning the selector knob to 'R' for five seconds

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like D.h.w. operation: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →