Daikin VRV IV RXTQ-TA / RXTQ-TB error code A3
Drain level control system abnormality
Which models this applies to. Indoor unit
Quick answer
On Daikin VRV IV RXTQ-TA / RXTQ-TB, A3 is a fault. It means drain level control system abnormality. A first thing to check: A blocked or kinked condensate drain pipe.
- Applies to
- Daikin VRV IV RXTQ-TA / RXTQ-TB
- Daikin VRV IV RXTQ heat pump codes · Heat Pump
- Type of code
- Fault
- Urgency: Book a technician
- First safe check
- Follow the drain pipe from the indoor unit and check it is not kinked, crushed or blocked, and that it slopes continuously to the drain.
What A3 means on this model
The condensate drain is not flowing or the water level has reached a point the control will not accept, so the unit has stopped rather than pour water into the room. This is the code that produces a drip in the room below.
Symptoms you will notice
- Indoor unit shows A3 and stops
- Water dripping from the indoor unit or the ceiling below it
- The indoor unit stops with no heating or cooling demand
- A drain pipe that is blocked or kinked
Common causes
The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:
- A blocked or kinked condensate drain pipe
- A failed drain pump
- A drain level sensor that is not reading correctly
- A float mechanism that has stuck or is dirty
- Sludge and biofilm in the drain pan after long service intervals
What you can safely check
These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.
- Follow the drain pipe from the indoor unit and check it is not kinked, crushed or blocked, and that it slopes continuously to the drain.
- Pour a small amount of water into the drain outlet and confirm it runs through rather than backing up.
- Pull the drain pan out on a cassette unit and look for the standing water and the debris that causes it.
Do not do these
- ×Do not poke a blockage clear with a wire without opening the pan, because the sharp sludge at the outlet can be part of a bigger blockage further down.
- ×Do not leave the unit running with a drain fault looking for a cooling problem. It is a stop code and the drain is the cause.
When to call a technician
Worth scheduling, and worth your own checks first
You can usually keep living with this for a short while, but it will not fix itself. Do the safe checks below first, because a tripped switch or a blocked airflow is a five-minute fix that would otherwise cost you a service call.
- The refrigerant circuit is sealed and legally requires licensed handling. Opening it without certification releases refrigerant and can put the whole system in violation of regulation, so a low-pressure or high-pressure fault on this equipment is a call-out, not a weekend job.
- If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.
Clearing a drain blockage from the outlet is a homeowner task. Anything involving the pan, the pump or the sensor is a technician job.
What it costs to fix
Parts
Drain pump $80 to $220. Drain level sensor or float $40 to $120.
Labor
One to two hours to clear the drain or replace the pump.
DIY or technician
Clearing a drain blockage from the outlet is a homeowner task. Anything involving the pan, the pump or the sensor is a technician job.
Typical US part and labor ranges, 2026. They vary by region, model and contractor, so treat them as a planning figure, not a quote.
Scope of this code
- Code table
- Daikin VRV IV RXTQ heat pump codes
- Models in scope
- Daikin VRV IV RXTQ-TA / RXTQ-TB
- Checked
- Confirm on your own unit
- Find the model number on the data plate, then check this code in the service manual for that model. Manufacturers revise code tables between model years, and a revised board can renumber a fault.