Common problems guide

The most common Heatline Capriz 25 System problems

The faults most likely to send a Heatline Capriz 25 System into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

This model is discontinued. Parts can be harder to source and expensive. If repair costs are mounting, a new A-rated boiler may be the smarter choice.
20 documented codes
6 most common
4 DIY-safe checks
2 engineer needed

The 6 most common faults

01
F0 High DIY-safe

Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.

What to try first

Locate the external filling loop, which is usually a small silver braided hose with one or two valves located underneath your boiler.Gradually open the valve(s) to allow mains water into the system while watching the pressure gauge on the front panel.Stop filling once the needle reaches the green zone, typically between 1.0 and 1.5 bar, then ensure the valve(s) are fully closed.

Est. cost
£80-120
Parts
Filling loop, Pressure relief valve, Pressure sensor
Full guide for F0
02
80 Flashing High DIY-safe

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

What to try first

Locate the filling loop (usually a silver braided hose under the boiler).Open the valves on the filling loop to allow cold mains water into the system.Monitor the pressure gauge on the front of the boiler until the needle reaches the green zone (typically 1.0 to 1.5 bar).Close both valves tightly and ensure the boiler resets.

Est. cost
£80-120
Parts
Filling Loop, Pressure Relief Valve, Pressure Sensor
Full guide for 80 Flashing
03
Bar LED Flashing High DIY-safe

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

What to try first

Locate the filling loop, which is a silver braided hose with one or two valves underneath your boiler.Open the valve(s) slowly to let water into the system until the pressure gauge needle on the front of the boiler reaches between 1 and 1.5 bar.Close the valve(s) tightly and the boiler should automatically restart.

Parts
Pressure Relief Valve (PRV), Expansion Vessel, Pressure Transducer
Full guide for Bar LED Flashing
04
F.22 High DIY-safe

Your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.

What to try first

Locate the external filling loop (a flexible silver hose with one or two valves) connected to the pipework underneath the boiler.Slowly open the valve(s) to allow mains water into the system while watching the pressure gauge on the front of the boiler.Close the valve(s) tightly once the needle reaches the green zone, typically between 1.0 and 1.5 bar.

Est. cost
£80-150
Parts
Pressure relief valve, Expansion vessel, Filling loop
Full guide for F.22
05
F1 High Engineer

Your boiler is failing to light because it cannot detect a flame, meaning you currently have no heating or hot water.

Est. cost
£120-250
Parts
Ignition electrode, Gas valve, Printed circuit board
Full guide for F1
06
F2 High Engineer

Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.

Est. cost
£120-250
Parts
NTC sensor, System pump, Primary heat exchanger
Full guide for F2

on the Heatline Capriz 25 System

Filling loopPressure relief valvePressure sensorFilling LoopPressure Relief ValvePressure Sensor

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Heatline shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
See the full 20-code list for the Heatline Capriz 25 System