Why won’t my Daikin switch between heating and cooling?

On a reverse-cycle unit, that’s usually the 4-way reversing valve or its solenoid coil. A technician can confirm whether it’s the coil (electrical) or the valve body (in the sealed circuit).

What does the expansion valve do?

The electronic expansion valve meters refrigerant flow to control the system’s capacity. A faulty EEV can cause weak cooling, icing, or the unit running constantly.

Can I replace a refrigeration part myself?

No. These parts are in the sealed refrigerant circuit, so fitting them involves recovering and recharging refrigerant — ARC-licensed work by law. It’s strictly for a licensed, ARC-accredited technician.

Why is ice forming on my outdoor unit’s pipes?

Icing can come from low refrigerant, airflow problems, or a faulty expansion valve. It needs a licensed technician to diagnose, as it usually involves the refrigerant circuit.

Are these parts model-specific?

Yes — they’re matched to the system’s capacity and refrigerant. Give us your model number and we’ll confirm the right genuine part.

Daikin Refrigeration Parts: Valves, Coils & Replacement

Genuine Daikin electronic expansion valve and reversing valve — National AC Parts

The refrigeration circuit is where your Daikin actually makes heat or cold — a sealed loop of refrigerant moved and metered by valves and coils. When one of these parts fails, the symptoms are specific: a unit that won’t switch modes, that loses capacity, or that can’t hold pressure. This guide explains the main refrigeration parts, what their faults look like, and why replacing them is specialist, ARC-licensed work.

The parts of the refrigerant circuit

A few key parts do the work. The electronic expansion valve (EEV) meters how much refrigerant flows, controlling capacity. The 4-way reversing valve switches a reverse-cycle system between cooling and heating. Stop (service) valves let a technician isolate and service the unit. The condenser coil rejects the heat the system collects. Solenoid and motorised valve coils operate the valves electrically.

Signs of a refrigeration-circuit fault

The unit won’t switch between heating and cooling (often the reversing valve or its coil).
Weak capacity, or the unit running constantly (can point to the expansion valve).
Ice forming on the pipework or coil.
A refrigerant leak, or the unit losing charge.
An error code relating to a valve or sensor feedback.

Reverse-cycle: the 4-way valve

On a reverse-cycle Daikin, the 4-way reversing valve is what flips the system between cooling and heating. If a unit heats but won’t cool (or the reverse), or gets stuck mid-changeover, the reversing valve or its solenoid coil is a prime suspect. The coil is the electrical part; the valve body is in the sealed circuit.

Why this is ARC-licensed work

Every part here is part of the sealed refrigerant circuit. Replacing one means recovering the refrigerant, brazing in the new part, and recharging — all ARC-licensed work under Australian law. It is strictly for a licensed, ARC-accredited technician and is never a DIY repair. (The electrical valve coils can sometimes be changed without opening the circuit — a technician will advise.)

Genuine Daikin refrigeration parts — matched to your system

These parts are matched to the system’s capacity and refrigerant type (such as R32 or R410A). A genuine, model-matched part integrates correctly with the circuit and controls. We carry the genuine Daikin refrigeration range — expansion valves and coils, reversing valves, stop valves and condenser coils.

How to find the right part

Daikin parts aren’t searchable by model number online, so tell us your model. Send a photo of your Compliance Plate or give us your model number, and we’ll confirm the right genuine part.

Daikin Refrigeration FAQs

If your Daikin won’t switch modes or has lost capacity, the refrigeration circuit is where to look — with a licensed technician. Browse our genuine Daikin refrigeration parts, or send your model number and we’ll match the exact part. Call 1300 904 554 or email daikin@nationalacparts.com.au.

ARC licence holder? Enter your promo code and licence number at checkout for your ARC discount on genuine Daikin spare parts.