Grant Spira Fault codes & diagnostics

25 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

System Oil 6-36 kW Discontinued

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Severity at a glance

Each cell = one fault code. Hover to identify.
1 Emergency 10 High 1 Medium 13 Low

All 25 documented codes

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03

Your boiler is currently idle and waiting for a signal from your thermostat or internal settings to tell it that your home needs more heat.

Low DIY-safe

What to check first

  1. Check your room thermostat is turned up to a temperature higher than the current room temperature
  2. Ensure your heating programmer or central heating timer is set to 'On'
  3. Check that any external weather compensation sensors are not faulty or obscured

Parts commonly replaced

  • Room thermostat
  • External sensor
  • Programmer module
15

Your boiler is currently moving its internal fuel grate to prepare for the fire, and it will automatically start once the process finishes.

Low Engineer only

Parts commonly replaced

  • Brazier motor
  • Brazier limit switch

Related codes

29

Your boiler is struggling to clear exhaust gases effectively because the internal fan or air sensors are not working as they should, causing the system to stop for safety reasons.

High Engineer only £180-350

Parts commonly replaced

  • Air pressure switch
  • Fan unit
  • Flue assembly seals
34

The mechanical component that manages the fuel or air flow inside your boiler is stuck and cannot move to its required position, preventing the boiler from starting.

High Engineer only £150-300

Parts commonly replaced

  • Pellet servo motor
  • Servo wiring harness
40

Your boiler is currently busy feeding wood pellets into the combustion chamber to get the fire started.

Low Engineer only

Parts commonly replaced

  • Pellet auger motor
  • Igniter element

Related codes

41

Your boiler is struggling to get the wood pellets to catch fire, so it is currently pausing its startup process.

High Engineer only £150-300

Parts commonly replaced

  • Igniter
  • Photocell
  • Pellet feed auger

Related codes

42

Your boiler is struggling to get the fire started and is slowly adding extra fuel to help build a strong flame.

Medium Engineer only £120-250

Parts commonly replaced

  • Igniter
  • Pellet feed motor
  • Brazier cleaning assembly

Related codes

Showing 11–20 of 25
45

Your boiler is currently monitoring the fire in the burner to ensure it stays lit after the initial ignition phase.

Low Engineer only

Parts commonly replaced

  • Igniter
  • Flame sensor
  • Pellet feed motor

Related codes

47

Your boiler has stopped working because one of its internal temperature sensors is not sending a clear signal, preventing it from safely heating your home.

High Engineer only £150-250

Parts commonly replaced

  • Temperature sensor (NTC probe)
  • Wiring harness
AIR PRESSURE ERROR

Your boiler is struggling to clear exhaust gases or draw in fresh air, so it has safely shut down to prevent unsafe operation.

High Engineer only £150-350

Parts commonly replaced

  • Air pressure switch
  • Flue fan
  • Venturi tube
BLANK DISPLAY SCREEN

Your boiler has lost all power and is completely unresponsive, meaning it cannot provide any heating or hot water until the electrical connection or internal safety switch is restored.

High Engineer only £150-350

Parts commonly replaced

  • Overheat Thermostat
  • PCB
  • Ribbon Cable
BOILER OVERHEAT STAT TRIPPED

Your boiler has automatically shut down to prevent damage because it has become too hot to operate safely.

High Engineer only £150-350

Parts commonly replaced

  • Overheat thermostat
  • Central heating pump
  • System filter
FAILED PELLET LIGHTING

Your boiler has stopped working because it has completely run out of wood pellets.

High DIY-safe

What to check first

  1. Check your bulk pellet store and hopper to confirm they are empty.
  2. Refill the pellet store with the correct grade of wood pellets.
  3. Follow the manufacturer's manual instructions to prime the feed system and reset the burner control panel.

Parts commonly replaced

  • Igniter element
  • Feed auger motor
PELLET FEED TUBE STAT TRIPPED

Your boiler has detected heat moving in the wrong direction through the pellet fuel system, which has triggered a safety shut-off to prevent fire risk.

Emergency Engineer only £150-300

Parts commonly replaced

  • Burn back thermostat
  • Delivery hose
  • Flue gas fan
PROBE FAULT

Your boiler has lost the signal from one of its internal temperature sensors, which is preventing it from heating your home safely.

High Engineer only £150-250

Parts commonly replaced

  • Temperature sensor
  • Wiring harness
  • Burner control unit
Showing 21–25 of 25
SERVICE

Your boiler has reached its scheduled maintenance interval and is simply reminding you that it is time for a professional annual service.

Low Engineer only £100-180

Parts commonly replaced

  • Service kit (seals, gaskets, filters)
SERVO MOTOR BLOCKED

Your boiler has stopped working because the mechanical part responsible for feeding fuel into the fire is stuck, likely due to a build-up of ash residue.

High Engineer only £150-300

Parts commonly replaced

  • Pellet feed motor
  • Burner grate