Electric wall/panel heater not working
A fixed electric heater (panel, wall, or in-slab) isn't heating — no warmth despite being switched on, pointing at the element, thermostat, controller, or supply.
Safety first
Isolate and prove dead before working. Fixed heaters can be on their own circuit/timer; in-slab heating is energised and not easily accessed.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Full detail — causes, the why, and common mistakes.
Likely causes
Ranked from most to least likely.
- 1
Thermostat/controller set or faulty
Most likelyThe thermostat or controller isn't calling for heat (setting, timer, or fault).
- 2
Failed element
#2The heating element has gone open circuit.
- 3
No supply / tripped protection
#3A tripped breaker/safety switch or lost supply.
- 4
Timer/controlled-load not energising (in-slab)
Least likelySlab heating often runs on a timer/controlled load; it may not be energised.
Reports are saved on this device to reflect what you actually find.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
Confirm the thermostat/controller is calling for heat and the timer/controlled-load is active.
Heat called; timer/controlled-load active when expected.
Heat called — check supply and the element.
Not calling / not in window — set correctly / chase the timer.
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
Electric heater not working
→ step 2 - 2decision
Is the thermostat/controller calling and timer active?
Yes→ step 3No→ step 4 - 3decision
Is protection on and supply present?
Yes→ step 5No→ step 6 - 4result
Set correctly / chase the timer/controlled-load.
- 5decision
Is the element resistance/insulation good?
Yes→ step 7No→ step 8 - 6result
Restore supply (find why if tripped).
- 7result
Re-check controller/timer.
- 8result
Open element or low insulation — replace/rectify.
Common mistakes apprentices make
- Not realising slab/panel heating runs on a timer or controlled load.
- Resetting protection without finding why it tripped.
- Assuming the element when the controller isn't calling.
- Working live on a heater circuit.
When to stop & escalate
Fixed heater work is licensed electrical. In-slab element faults can be major (the element is in the slab) — get a licensed electrician to assess before assuming the worst.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
Related faults
No hot water (electric storage system)
An electric storage hot water system has gone cold — no hot water at the taps. Usually the element, thermostat, supply, or (for off-peak) the tariff/timing.
Heater not heating at all
A heater (element, band, or bank) produces no heat — temperature won't rise, the process stays cold, despite the control calling for heat.
A circuit breaker keeps tripping (domestic)
One circuit breaker keeps tripping — instantly on reset or after a load runs — and you need to tell an overload from a short or a faulty appliance.