Brivis fault code h01 41
Supply-air overheat switch tripped.
What h01 41 actually means
The supply-air overheat switch has tripped. That is the safety on the outlet side of the heater, so the heater is making heat but it is not getting away down the ducts fast enough.
What causes it
- Ceiling vents closed or blocked, especially in bedrooms nobody uses
- A crushed, kinked or disconnected flexible duct in the roof space
- An undersized or partly blocked return-air path
- A fan running slow or failing
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.
- Open every ceiling vent in the house and leave them open
- Check nothing is covering a vent, including furniture directly under one
- Look at the return-air filter and clean or replace it
- Restart the heater after ten minutes and see whether it holds
What we check on site
So you know what you’re paying for.
- Static pressure test across the system
- Walk the roof space and check every branch duct for crushing or disconnection
- Confirm fan speed setting matches the duct design
- Test the supply-air overheat switch and thermistor
Can you keep using it?
Once, on a cold night, with the vents opened up, it is generally fine. Repeatedly, no. Same reasoning as h01 40: overheat cycling is what damages a heat exchanger.
What the fix usually involves
Usually ductwork rather than the heater. Reconnecting or replacing a collapsed branch, or rebalancing the system so the air has somewhere to go.
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 →