Error Red LED on - the boiler won't run once switched on: No 12 V power supply or battery voltage too low (< 10.5 V).

Check battery voltage, check boiler fuse (1.6 A slow-acting) on electronic control unit.

Error Red LED comes on after roughly 30 seconds - the boiler won't run: Could be a fitted cowl cover, no gas supply, wrong gas pressure, or air in the gas line.

Take off the cowl cover, check the gas valves and cylinder, then switch the appliance off for 5 minutes and back on to bleed the air.

Error Boiler switches to Fault after long period of operation: Overtemperature sensor has activated.

Check the water content and top it up if low by closing the drain valve, then switch the appliance off for 5 minutes and back on.

Error Water dripping from drain valve: Water pressure too high (> 2.8 bar).

Check the water pressure and fit a pressure reducer if it's on mains water.

Error Warm water comes out of the cold tap: Hot water is flowing back into the cold supply.

Fit a non-return valve on the cold supply line.

← Back to Appliance Troubleshooting

Truma • Water Heaters

Truma Gas Boiler

Q: Error Red LED on - the boiler won't run once switched on: No 12 V power supply or battery voltage too low (< 10.5 V).

Check battery voltage, check boiler fuse (1.6 A slow-acting) on electronic control unit.

Q: Error Red LED comes on after roughly 30 seconds - the boiler won't run: Could be a fitted cowl cover, no gas supply, wrong gas pressure, or air in the gas line.

Take off the cowl cover, check the gas valves and cylinder, then switch the appliance off for 5 minutes and back on to bleed the air.

Q: Error Boiler switches to Fault after long period of operation: Overtemperature sensor has activated.

Check the water content and top it up if low by closing the drain valve, then switch the appliance off for 5 minutes and back on.

(BGF)

The Truma Boiler Gas BGF is a liquid gas-powered water heater designed exclusively for installation and operation in caravans, motor homes, and mobile homes. It heats drinking water up to approximately 70 °C and can be operated simultaneously with gas and electricity for faster heating.

View official manual on manufacturer's site ↗

Technical Specifications

Gas Pressure Mbar30 mbar

Power Consumption 12vIgnition: 0.25 A, Heating: 0.21 A, Standby: 0.06 A

Water Capacity Litres10 litres

Weight Kg7.5 kg

Master Troubleshooting & Diagnostics Matrix

Error Code / Indicator	Symptom / Meaning	Possible Cause	Step-by-Step DIY Fix	Suggested Actions
`Red LED on - the boiler won't run once switched on`	No 12 V power supply or battery voltage too low (< 10.5 V).	—	Check battery voltage, check boiler fuse (1.6 A slow-acting) on electronic control unit.	DIY Safe
`Red LED comes on after roughly 30 seconds - the boiler won't run`	Could be a fitted cowl cover, no gas supply, wrong gas pressure, or air in the gas line.	—	Take off the cowl cover, check the gas valves and cylinder, then switch the appliance off for 5 minutes and back on to bleed the air.	DIY Safe
`Boiler switches to Fault after long period of operation`	Overtemperature sensor has activated.	—	Check the water content and top it up if low by closing the drain valve, then switch the appliance off for 5 minutes and back on.	DIY Safe
`Water dripping from drain valve`	Water pressure too high (> 2.8 bar).	—	Check the water pressure and fit a pressure reducer if it's on mains water.	DIY Safe
`Warm water comes out of the cold tap`	Hot water is flowing back into the cold supply.	—	Fit a non-return valve on the cold supply line.	DIY Safe

Frequently Asked Questions

Q: I can smell gas - what should I do?

Remove any ignition sources - put out naked flames, don't touch electrical switches, phones or radios, and don't start the engine. Open the windows and doors, get everyone out of the vehicle, shut off the gas cylinders or supply from outside, and have the gas system checked by qualified experts.

Q: Can I operate the boiler while driving?

Yes, as long as a safety shut-off device such as the Truma MonoControl CS is fitted to UN ECE regulation 122 - otherwise the gas cylinder needs to be closed while travelling.

Q: How do I clear a fault indicated by the red LED?

Switch it off at the control panel, wait 5 minutes, then switch back on.