Common problems guide

The most common Potterton Ultra 2 30 DV problems

The faults most likely to send a Potterton Ultra 2 30 DV 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.
18 documented codes
6 most common
3 DIY-safe checks
3 engineer needed

The 6 most common faults

01
Red Neon High DIY-safe

Your boiler has stopped working for safety reasons and needs to be manually restarted to begin its ignition sequence again.

What to try first

Locate the reset button on the underside of the boiler towards the right-hand side.Press and release the button firmly to attempt a reset.Wait a few minutes to see if the burner ignites and the red light turns off.

Est. cost
£100-250
Parts
Ignition electrode, Gas valve, Printed circuit board (PCB)
Full guide for Red Neon
02
Green light flashing slowly High DIY-safe

Your boiler is currently in standby mode because it is not receiving a signal from your thermostat or timer to turn on your heating or hot water.

What to try first

Check that your heating timer or programmer is set to 'ON' and the screen is active.Increase the temperature setting on your room thermostat to see if the boiler responds.Ensure your external controls have power and replace their batteries if applicable.

Est. cost
£90-180
Parts
External programmer, Room thermostat, Wiring centre
Full guide for Green light flashing slowly
03
Low system pressure High DIY-safe

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

What to try first

Locate the external filling loop, usually a small braided metal hose connecting two pipes near the boiler.Open the small valves at either end of the loop slowly until you hear water flowing.Watch the pressure gauge on the front of the boiler until the needle reaches 1.5 bar, then securely close both valves.

Parts
Filling loop, Pressure relief valve, Expansion vessel
Full guide for Low system pressure
04
Permanent Live 'On' High Engineer

Your boiler is receiving a constant electrical signal telling it to run, which prevents it from properly starting or finishing its normal heating cycle.

Est. cost
£150-300
Parts
Ignition printed circuit board, Wiring harness, External programmer or timer
Full guide for Permanent Live 'On'
05
Reversed Polarity 'Off' High Engineer

Your boiler has detected that the electrical wiring supplying it is connected backwards, which prevents it from operating safely.

Est. cost
£90-160
Parts
Fused spur, Electrical wiring
Full guide for Reversed Polarity 'Off'
06
Lockout High Engineer

Your boiler has stopped working for safety reasons and has locked itself to prevent starting until a professional technician can investigate the internal fault.

Est. cost
£150-350
Parts
Ignition PCB, Gas Valve, Flame Sensing Electrode
Full guide for Lockout
Parts most often replaced

on the Potterton Ultra 2 30 DV

Ignition electrodeGas valvePrinted circuit board (PCB)External programmerRoom thermostatWiring centre

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 Potterton 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 18-code list for the Potterton Ultra 2 30 DV

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →