E3Daikin · VRV IV RXTQ-TA / RXTQ-TB · Heat Pump

Daikin VRV IV RXTQ-TA / RXTQ-TB error code E3

High pressure switch activation

Needs attention soon

Also written as high pressure, high pressure switch, head pressure, E3

Which models this applies to. Outdoor unit

Quick answer

On Daikin VRV IV RXTQ-TA / RXTQ-TB, E3 is a fault. It means high pressure switch activation. A first thing to check: A refrigerant overcharge.

Applies to: Daikin VRV IV RXTQ-TA / RXTQ-TB; Daikin VRV IV RXTQ heat pump codes · Heat Pump
Type of code: Fault; Urgency: Needs attention soon
First safe check: Look at the outdoor unit from a safe distance and confirm the condensing fan is actually turning at full speed before anything else.

Checked 2026-09-26

What E3 means on this model

A mechanical high pressure protection has opened and shut the system down. It does not reset on its own, and resetting it without finding why it tripped is the classic way to burn a compressor. A dirty coil, a slow outdoor fan and an overcharge are the usual causes.

Symptoms you will notice

Outdoor unit shows E3 and the system stops
The system runs for a while then stops
The system stops in hot weather or on high indoor load
The system stops after a defrost cycle

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 refrigerant overcharge
A condensing unit fan that is not moving enough air
A blocked or dirty outdoor coil
An outdoor fan motor that has lost speed or stopped
A high pressure switch that is chattering near its set point
A failed condenser fan capacitor
An indoor unit or EEV fault that is driving the system into high head pressure
A restricted refrigerant circuit

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.

Look at the outdoor unit from a safe distance and confirm the condensing fan is actually turning at full speed before anything else.
Check the outdoor coil for dirt, debris and blocked airflow around the unit.
Confirm the unit has clear air movement across the coil and that nothing is obstructing the fan or the coil face.

Do not do these

×Do not reset the high pressure switch and restart the system without finding the cause. This switch is protecting the compressor and repeated resets destroy it.
×Do not block the outdoor coil to improve airflow elsewhere. That is one of the ways this switch trips in the first place.
×Do not add refrigerant to clear an E3. If the pressure is high the charge is not the low side of the problem.

When to call a technician

Book a technician, do not keep resetting it

This fault will not clear on its own. Every power cycle gives the control one more failed attempt, and repeated attempts are what turn a cheap part replacement into a seized or contaminated system.

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.

Cleaning a dirty outdoor coil and clearing debris around the unit are reasonable homeowner tasks. Anything involving the switch, the charge or the fan motor is a technician job.

What it costs to fix

Parts

High pressure switch $60 to $180. Condenser fan motor $300 to $700. Fan capacitor $30 to $80.

Labor

Two to four hours to diagnose properly, more if refrigerant work is needed.

DIY or technician