Truma Boiler Issue

Boris7

Boris7

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So this morning my boiler won’t run. I’m getting error 89 (12v battery low)

The leisure battery is showing 13.v and is at 86%

Having tried many times to issue just continues.

Plugged into EHU (via EcoFlow) and boiler fires straight up no issues.

Obviously I’ve got the option of EHU so no urgent issue.

But any ideas as to why the trauma thinks the 12v battery is below 10.5v ?
 
Boris7 said:
So this morning my boiler won’t run. I’m getting error 89 (12v battery low)

The leisure battery is showing 13.v and is at 86%

Having tried many times to issue just continues.

Plugged into EHU (via EcoFlow) and boiler fires straight up no issues.

Obviously I’ve got the option of EHU so no urgent issue.

But any ideas as to why the trauma thinks the 12v battery is below 10.5v ?
Click to expand...
My 2021 purchase KS Energy Lithium Battery had a BMS that would allow the battery to go to sleep when fully charged; I could set my clock by the error - each evening about 45 minutes after the lights and/or heating were turned on, well within the battery's output capabilities, the fridge would call for a teaspoonful of leccy to spark the refrigeration, the BMS couldn't respond from its doze quickly enough, the lights would flicker for 1/2 second, and the 12v system threw a hissy fit, with the Pioneer multimedia losing all settings, and the Truma threw an error code 'low battery voltage - turn appliances off to preserve battery'; can't remember the error code number exactly, but 89 rings a bell. Never had the fault when I changed to a Roamer Battery 2.5 years ago, or when I replaced the Roamer with a Polar Lithium in March 2026. The more modern BMS designs seem to have been redesigned to prevent the battery from going comatose when 'on shift' ... HTH

Steve
 
It might not be to do with voltage. I think I have seen this come up before.

Google AI

Error 89 (E89H) is not actually a battery warning. On Truma Combi boilers, it primarily indicates a combustion air motor, fan issue, or electronics failure. The boiler misinterprets the stalled fan/motor as a massive voltage drop, causing it to display a fake "12v low" code. [1, 2, 3]
Because the fan demands less power when the boiler's 12V system is supplied by an external hookup (via your EcoFlow), it masks the underlying fan/motor fault, which is why it fires up straight away on EHU. [1]
Forum consensus points to three typical causes:
  • Carbon buildup: The combustion motor can build up carbon residue over time.
  • Stiff or faulty fan motor: The fan struggles to spin properly on 12V alone.
  • Electronics/PCB fault: The main control board is malfunctioning and misreading data. [1, 2, 3]
You can check out this Truma Combi Boiler Error Code Update video, which discusses exactly what happens when carbon builds up and triggers this motor error.
 
Sorted.

Good man Barry 👍

Removed fan cover and cleaned it thoroughly code changed to 212 (no gas) checked gas bottle all good, then used it to light BBQ just to be sure swapped bottles, heater ran for 10 mins then stopped code 69.

Reset boiler now running fine.

Booked in for a Truma service next month just to be sure
 
Boris7 said:
Sorted.

Good man Barry 👍

Removed fan cover and cleaned it thoroughly code changed to 212 (no gas) checked gas bottle all good, then used it to light BBQ just to be sure swapped bottles, heater ran for 10 mins then stopped code 69.

Reset boiler now running fine.

Booked in for a Truma service next month just to be sure
Click to expand...

Yeah. Any motorhome tech questions. I'm yer man! :LOL:
 
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