PB, shown as nine flashes on units that signal by blink pattern, is about the fan inside your wall unit. Here is what it means.
What PB means
Mitsubishi Electric PB indicates an indoor unit fan motor error. The blower that pushes cold air into your room is not running correctly, or the board is not receiving the feedback it expects from it. High severity in the Mitsubishi table because without indoor airflow the system cannot work and the coil can freeze. Full list and blink patterns in our Mitsubishi error codes guide.
What usually causes PB in Singapore
The honest list, cheapest first: a blower wheel so caked with dust and biofilm that the motor cannot spin it freely, something physically obstructing the wheel, a wiring or connector fault between motor and board, then the motor itself, and least often the indoor control board misreading a healthy motor. Units that have gone a long time without a proper wash sit at the top of that list, and in our humidity that happens faster than owners expect.
What you can safely try
Power off at the breaker for five minutes and restart once. If PB returns, leave the unit off. Running a system with a struggling indoor fan can freeze the coil and turn a modest repair into a bigger one.
What our technician does
Check the blower wheel and airflow first, because a heavy clean fixes a real share of PB calls, then test the motor and its wiring, and only then look at the board. Nobody should be quoted a motor before someone has looked at the wheel.
What it costs
If the cause is a filthy blower, a chemical overhaul at published rates solves it and the unit comes back better than before. A motor replacement is a mid range repair. Diagnosis rates are on our aircon repair in Singapore page.
PB showing right now?
WhatsApp +65 8818 5781 with your model number and a photo of the display. We will tell you honestly whether it is a quick fix, a repair worth doing, or nothing to worry about. Our aircon repair in Singapore service covers every brand with published rates and a 30 day labour warranty.
