Truma combi fault codes

Truma Combi Boiler Fault Codes

Truma Combi Boiler Fault Codes

The latest Truma Combi boilers are getting more and more clever and you are now even able to control the boiler and air conditioning in your van with a phone app. With all its technology the Boiler can now tell you if there’s an issue, this is where fault codes come in.

If your van has a Truma CP panel (pictured above) it can display any errors that are occurring with the boiler, here is a list of the most common Truma combi boiler fault codes and what the numbers mean for that panel.

Last update on 2023-01-08 / Affiliate links / Images from Amazon Product Advertising API

Truma combi fault code table

Fault CodeCauseRemedy
17Summer mode with an empty boiler.Switch combi off and allow to cool down.
18Warm air temp exceeded:
Not all warm air ducts connected.
Warm air outlets blocked.
Circulated air intake blocked.
Check air ducts/pipes are connected.
Check the outlet openings.
Remove the intake blockage.
21Room temp sensor/cable faultyInspect cable, replace if faulty.
24Battery voltage low <10.4vCharge battery.
29Frost control element short circuit.Disconnect element plug/replace element.
42Open window above exhaust cowl, window switch.Close window.
43Over voltage >14.6vCheck battery/ charger.
44Low voltage <10.0vCharge battery.
45No 230v supply to boiler.
230v fuse blown on pcb.
Overheating protection triggered.
Restore operating voltage.
Replace fuse.
Reset overheat protection.
112Gas cylinder empty.Replace gas cylinder.
121Gas cylinder closed.Open gas valves.
122As above
212Butane content too high.
Combustion air infeed or exhaust blocked.
Gas reg. faulty
Use propane bottle.
Inspect openings for obstructions i.e snow.
Inspect replace gas regulator.
255Heater has no 12v supply.
No connection between panel and boiler.
Check 12v supply.
Remake connection to panel.
301Over voltage >16.4vCheck battery/ charger
417As above
302Low voltage <10vCharge battery
303Risk of low voltage <10.4vCharge battery.
401Summer mode with empty boilerSwitch off and allow to cool.
402Warm air temp exceeded.
Not all air pipes connected.
Warm air outlets blocked.
Circulated air intake blocked.
Check air pipes are connected.
Check the air outlets are not blocked.
Remove the intake blockage.
407No 230v supply.
230v fuse blown on combi pcb.
Restore operating voltage.
Replace fuse.
408No gas supply in mix mode.Check gas supply.
412Open window above exhaust cowl, window switch.Close window.
418Low voltage <10vCharge battery.
419Overheating protection triggered.Reset overheating protection.
507Gas cylinder empty.Replace gas cylinder.
514Incorrect shutdown, 12v lost during use.Reset boiler see below.
516Gas cylinder or quick acting valve closed.Check gas and open valves.
517Combustion air infeed or exhaust outlet blocked.
Gas reg. faulty.
Inspect openings for obstructions i.e snow then remove.
Inspect then replace regulator.
60212v spike, usually from solar panel installation or no leisure battery when solar panels fitted.New pcb may be required, try reset pcb first.
607Max number of fault resets reached.Wait 15 mins and reset boiler.
621Room temp sensor or cable fault.Inspect cable.
624Frost control element short circuit.Disconnect heating element plug, replace heating element.
LE Rechargeable Camping Lights, 500 Lumen Bright LED Torch, 5 Modes Camping Lantern with 2600mAh Power Bank, Large Rechargeable Torch for Hiking, Fishing, Power Cuts, Emergency and More
  • 【High Brightness】 Made of superb LED, the main beam of LED...
  • 【USB Rechargeable and Power Bank】 Built-in 2600mAh...
  • 【Easy to Use】 With a handle on the body, you can easily hold...

Last update on 2023-01-08 / Affiliate links / Images from Amazon Product Advertising API

Clearing codes

To clear the above fault codes carry out the remedy as necessary and the boiler in most cases with rectify itself. If the code remains use the CP panel scroll knob to select the warning triangle and either double click it or push and hold until “app” appears and then use the “back “ button this should clear it if the remedy has been carried out. If the fault is still persistent or “wait 15 mins” appears you can do a “boiler reset” (disconnecting the 12v supply is not a reset).

To do this you need to slide up and remove the black plastic cover that hides the connections.

truma combi issue
Combi Boiler
truma error codes
Push cover in the upwards direction

 Once the cover has been removed it reveals the 12v circuit board. Locate the reset button pictured here (below).

truma combi boiler reset
Truma Boiler reset button

The reset button will have a small L.E.D light next to it flashing red. Press and hold the reset button for approx 5 seconds, the red light should now turn yellow. Release the reset button. When the reset is successful the L.E.D goes out and you will hear a couple of relay clicks and the boiler goes into standby mode. The boiler should now operate as normal.

I hope this guide has helped, there’s nothing worse than being away and you have no heating or hot water!

If you found this list helpful you may be interested in this article also on our site – Finding the best solar panel

Handy link – Truma home page

Check out some of our other articles...


     Please note these are the words and opinion of the author only. Neither the author nor the website can be held responsible for any errors or omissions. You should seek professional assistance if in doubt.