Braemar fault code 23
Overheat lockout.
What 23 actually means
Overheat lockout. The heater has got too hot inside and shut itself down. On Braemar ducted units this is nearly always airflow rather than anything wrong with the burner.
What causes it
- Return-air filter blocked, the most common cause by a distance
- Ceiling vents closed through most of the house
- Crushed or disconnected ductwork in the roof
- Main fan slowing or failing
- Return-air grille obstructed by furniture
Most likely first. That order is from what we actually find on site, not from the manual.
Safe to check yourself
No tools, no covers off, nothing to do with gas, refrigerant or wiring.
- Take the return-air filter out and check you can see light through it
- Open every ceiling vent, including in rooms nobody uses
- Move anything sitting against the return-air grille
- Let it cool completely, then reset once
What we check on site
So you know what you’re paying for.
- Temperature rise across the heat exchanger against the data plate
- Fan speed and current draw
- Static pressure test
- Duct inspection in the roof space
- Overheat switch test
- Heat exchanger inspection and carbon monoxide test
Can you keep using it?
Not repeatedly. One reset after clearing a filter is reasonable. If it locks out again, leave it off. Overheat cycling is what cracks heat exchangers, and Braemar units of a certain age are exactly the ones we find cracked.
What the fix usually involves
Usually filter and ductwork. The heat exchanger inspection that comes with the service call is the part that matters, because it decides whether the heater is worth keeping.
Is it worth fixing?
That depends almost entirely on how old the unit is. Past about ten years on hot water and gas heating, and twelve on aircon, a significant repair usually costs more per remaining year than a replacement does — and it’s the same point at which the VEU rebate is worth the most, because old inefficient appliances are exactly what the scheme pays to remove. If yours is young and the fault is a component, we’ll fix it and say so.
Repair or replace? The 10-year rule, and what the rebate is worth →