Intergas Furnaces Error Codes

Symptom

Boiler/furnace does not start, display shows code 0, no ignition attempt heard

No Heat Demand / Standby Lockout

1

Furnace attempts to start but locks out with code 1, no flame established

Ignition Failure / No Flame Detected

10

Boiler shows code 10 and will not fire, fan may not start

Fan Speed / Tachometer Fault

11

Code 11 displayed, boiler locks out, may be related to gas valve control

Gas Valve Control / Modulation Error

12

Boiler intermittently shows code 12, resets may temporarily restore operation

Low System Water Pressure / Flow Fault

13

Code 13 displayed, boiler stops, may be associated with condensate issues

Condensate Drain / Siphon Fault

14

Boiler shows code 14, no heating output, pump may not run

Pump Fault / No Circulation

15

Code 15 appears, boiler locks out, may be related to flue gas temperature

Flue Gas Temperature Overlimit

16

Boiler shows code 16, erratic behavior of display and controls

Control PCB / Internal Error

17

Code 17 displayed, boiler does not respond to external controls correctly

Communication Fault with Room Thermostat / OpenTherm

18

Boiler shows code 18, may be associated with low voltage or power issues

Mains Supply / Low Voltage Fault

19

Code 19 displayed, boiler fails to start, may be related to safety chain

Safety Circuit Open (Limit Switch / Safety Chain Fault)

2

Furnace locks out with code 2 shortly after ignition, burner shuts down

Flame Loss During Operation

3

Display shows code 3, furnace does not start, fan may run briefly

Air Pressure / Fan Fault

4

Boiler shows code 4 and will not fire, may occur intermittently

Flow Sensor / NTC Fault (Heating Circuit)

5

Display shows code 5, boiler shuts down on high temperature

Overheat Thermostat / Safety Cut-out Tripped

6

Code 6 displayed, boiler will not run, may be accompanied by very high temperature reading

Flow Temperature Sensor Overrange / Short Circuit

7

Code 7 on display, boiler does not respond to hot water demand

DHW Temperature Sensor / NTC Fault

8

Code 8 displayed, boiler cycles rapidly or does not modulate correctly

Flow Sensor / Turbine Fault (DHW Flow Detection)

9

Code 9 appears, boiler stops and may show abnormal temperature readings

Return Temperature Sensor / NTC Fault

Symptom

Boiler display is blank, no lights, unit completely dead

No Power / Dead Appliance

Symptom

Boiler display works but buttons or controls do not respond properly

User Interface / Control Panel Fault

Symptom

Boiler fan runs but burner does not light, no error code displayed

No Ignition Without Fault Code

Symptom

Boiler frequently locks out during very cold weather, condensate pipe outside is icy

Frozen Condensate Pipe

Symptom

Boiler ignites with a loud bang or pop

Delayed Ignition

Symptom

Boiler loses pressure over time, user must frequently top up system

Chronic Pressure Loss

Symptom

Boiler pressure rises rapidly when heating, relief valve discharges water

Over-Pressurization / Expansion Vessel Failure

Symptom

Boiler runs but some radiators stay cold or only partially warm

Poor Circulation / System Balancing Issue

Symptom

Boiler will not start after summer, pump or fan appears stuck

Seized Components After Long Inactivity

Symptom

Condensate water dripping from flue joints or boiler casing

Condensate Leakage from Flue System

Symptom

Furnace frequently cycles on and off, short burner run times, room temperature unstable

Short Cycling

Symptom

Furnace is very noisy during operation, whistling or roaring from burner area

Combustion Noise / Burner Resonance

Symptom

Furnace makes loud banging or knocking noises when starting or stopping

Water Hammer / Thermal Expansion Noise

Symptom

Furnace or boiler casing vibrates excessively, humming felt through walls

Mechanical Vibration / Imbalance

Symptom

Furnace runs but radiators or air handlers do not get hot enough, long heat-up times

Underheating / Insufficient Output

Symptom

Radiators get hot but domestic hot water temperature fluctuates or is too cold

Poor DHW Performance

Symptom

Soot or scorch marks around flue terminal or boiler casing

Incomplete Combustion / Flue Gas Spillage

Symptom

Strong smell of gas near the Intergas furnace/boiler

Gas Leak

Symptom

Water leaking from the bottom of the Intergas furnace/boiler casing

Internal Water Leak