TQ DGH - FC20, FC21, FC35 & FC36 Flame Roll-out Faults – Flame Roll-out Bridge Loom (P/N 651071)
⚠️ Safety Notice – Gas Heating Products
This appliance must only be installed, commissioned, serviced and repaired by suitably qualified and licensed personnel.
Before commencing work, complete a task-specific risk assessment and ensure gas and electrical safety requirements, ventilation provisions, safe access, adequate service clearances and appropriate PPE have been considered. All work must comply with applicable regulations, standards and manufacturer requirements.
Particular care must be taken when working around gas systems, electrical components, combustion products, hot surfaces, moving parts, roof spaces, ceiling spaces and confined spaces.
Do not proceed if safe access, required clearances, ventilation requirements, confined space risks or appropriate safety controls cannot be achieved and maintained.
Safety takes priority over diagnosis, repairs, installation schedules and customer expectations. If the task cannot be completed safely, it must not proceed until the risks have been adequately controlled.
Applicable Fault Codes
- FC20 – Flame Roll-out Detected During Start
- FC21 – Flame Roll-out Detected During Run
- FC35 – Flame Roll-out Circuit Check Failed
- FC36 – Flame Roll-out Loom Not Attached or Short Circuit to Ground
Retrieving Fault History
Stored fault codes can be viewed using the MagIQtouch Controller:
SETTINGS → SERVICE → GAS HEATER 01 → Enter PIN 7378 → FAULT LOG
The 10 most recent fault codes are stored and can assist with diagnosis.
Recommended Video: MagIQtouch Heater Fault Log YouTube Video
Supporting reference articles -
TQ DGH - Gas Valve Identification and Gas Pressure setting: Seeley International Pty Ltd
What is the Flame Roll-out Detection Window?
The flame roll-out detection window is a small metal sensing plate mounted on rubber insulators near the front of the burner assembly. It was originally designed to detect flames escaping outside the normal burner area due to combustion issues such as blocked heat exchanger passages, burner faults, or other abnormal operating conditions.
Important Information
The flame roll-out detection window is a legacy component and is no longer used on current production heaters.
Units manufactured after 17 January 2018 were supplied with a flame roll-out bridge loom (P/N 651071) instead of the flame roll-out detection window system. The manual-reset OT3 flame roll-out over-temperature switch remains a mandatory safety device and must always remain connected.
Recommended Checks
Before replacing or bypassing the flame roll-out detection window, confirm there is no evidence of genuine flame roll-out by checking:
- Heat exchanger tubes are not blocked or heavily restricted.
- Burners are correctly installed and aligned.
- Injectors are correct for the heater model and gas type.
- Gas manifold is not leaking.
- No visible flame disturbance or flames escaping from the burner area.
- OT3 manual reset over-temperature switch has not operated.
Refer to the relevant fault code diagnostics if a genuine combustion issue is suspected.
Resolution
If there is no evidence of actual flame roll-out and FC20, FC21, FC35 or FC36 continue to occur:
- Disconnect the flame roll-out detection window and associated wiring.
- Install Flame Roll-out Bridge Loom P/N 651071.
- Confirm all wiring connections are secure.
- Reset the fault and test heater operation.
Important: The manual-reset OT3 flame roll-out over-temperature switch on the burner cover must remain installed and wired in series with the gas valve at all times. OT3 must never be bypassed or disconnected.
Parts Required
| Part Number | Description |
|---|---|
| 651071 | Flame Roll-out Bridge Loom |
Fault code history can be accessed:
SETTINGS/SERVICE/GAS HEATER 01/7378 CONT/FAULT LOG
YouTube Video - MagIQtouch Heater Fault Log
The flame roll-out detection window is a small metal sensing plate mounted on rubbers near the front of the burner assembly. It was designed to detect flames escaping outside the normal burner area due to issues such as blocked heat exchangers or burner faults.
No evidence of flame roll-out?
If there are no visible signs of flame roll-out and FC20, FC21, FC35 or FC36 continue to occur, the flame roll-out stainless-steel window system may be replaced with Bridge Loom P/N 651071.
The flame roll-out window is a legacy component and is no longer fitted to current production heaters.
Important: The manual-reset 130°C OT3 Flame Roll-out Switch (image below) located on the burner housing lid must remain fitted and wired in series with the gas valve. It is a critical safety device and must never be bypassed.
