Medium
Noises in CH system on Chaffoteaux Calydra 23 Green

Your boiler is making unusual sounds because the water pressure is too low or there are air bubbles trapped inside the system.

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

Air presence in C.H. system or Insufficient pressure

From this model's manual
Verified against the Chaffoteaux Calydra 23 Green 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 the pressure gauge and use the filling loop to top it up to 1.5 barBleed your radiators using a radiator key to release any trapped airRestart the boiler to see if the noises persist

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 Noises in CH system: 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

Boiler keeps losing pressure

Six most common causes of dropping pressure.

Read →

Low pressure — repressurise guide

Step-by-step using the filling loop.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →