W 45 H120-volt supply missing or overheat protection active
Applicable plus models either lack AC power or have activated overheating protection.
Plain-English answer
On Combi eco plus and comfort plus models, W 45 H can mean no 120-volt AC supply or an activated overheating protector. Truma recommends checking the AC connection first.
What to check first
- 01
Confirm shore or generator power is available to the RV.
- 02
Check the assigned breaker using the RV owner's manual.
- 03
Allow the Combi to cool and make sure air outlets and intakes are unobstructed.
Stop and call a technician when
- Do not open a live breaker panel or appliance housing.
- Contact Truma support if AC power is confirmed and the warning remains.
Check the exact manual
Applicability: Truma Combi eco plus and comfort plus models. The data plate and specification letter determine which procedure is correct.
Open Truma Combi error-code tech tip ↗Source reviewed August 2026Check AC power, then contact Truma if unresolved
On North American plus models, check the AC supply first. Timing alone does not identify the cause.
Confirm the 120-volt path
Verify the RV is actually receiving shore or generator power and check the assigned breaker using normal controls. Do not remove the panel cover or probe energized wiring.
Contact Truma Customer Care
If the supply is confirmed or restored and W45H remains, contact Truma Customer Care. Do not attempt internal electrical repairs.
Record mode and model
Note whether gas heat still operates, photograph the code, and record the data-plate model. That distinction helps Truma service separate an AC-supply problem from an internal overheat fault.