I really appreciate how honest and efficient this company is. They identified the problem quickly and fixed it without unnecessary charges. I would definitely recommend them!
M
Matthew Lim
Aircon Expansion Valve Repair in Singapore
The expansion valve controls how much refrigerant enters the evaporator coil. When it sticks, clogs, or fails, the unit either freezes up or loses cooling entirely. We test the valve and its control circuit before recommending repair or replacement.
How we approach expansion valve issues
Confirm before opening the circuit
Opening the refrigerant circuit means recovery, vacuum, and recharge. We only do this when diagnosis confirms the valve is the problem.
Check the control side too
For electronic expansion valves, the fault is sometimes in the PCB or wiring rather than the valve itself. We check both before quoting a valve swap.
Proper recommissioning after repair
After any valve work the system is vacuumed, leak-tested, and recharged with the correct quantity. Shortcuts here cause repeat problems.
Signs of an expansion valve problem
These symptoms suggest a metering issue in the refrigerant circuit. The expansion valve is one of the most common causes, but we confirm before replacing.
- Ice forming on the indoor unit or copper piping
- Unit cools for a few minutes then stops cooling
- Evaporator coil partially cold and partially warm
- Hissing or whistling noise near the indoor unit
- System short-cycling — turning on and off repeatedly
- Abnormal suction or discharge pressure readings
How expansion valve diagnosis works
Valve faults share symptoms with low gas, blocked filters, and dirty coils. We eliminate the simpler causes first before opening the refrigerant circuit.
1. Symptom and pressure check
We measure suction and discharge pressures while the system runs. Abnormal pressure readings narrow the fault to the metering device, gas charge, or compressor.
2. Rule out simpler causes
Dirty filters, blocked coils, and low refrigerant can mimic valve symptoms. We check and clear these before suspecting the valve itself.
3. Valve inspection
We check the valve body temperature, superheat readings, and — for electronic valves — the control signal from the PCB. This confirms whether the valve is stuck, clogged, or electrically faulty.
4. Diagnosis and recommendation
We confirm whether the valve needs cleaning, recalibration, or full replacement. For electronic expansion valves, the fault may be in the valve motor or the PCB controlling it.
5. Repair and recharge
After valve repair or replacement, the system is vacuumed, recharged with the correct refrigerant quantity, and test-run to confirm normal superheat and cooling output.
Pricing
Cost depends on the valve type — thermostatic (TXV) or electronic (EEV) — and whether the unit needs a full valve replacement or a supporting repair.
- Diagnostic visit includes pressure and superheat measurements
- TXV cleaning or adjustment is less costly than a full swap
- EEV replacement includes the valve motor and control check
- No work starts until you agree to the quote
Booking and visit timing
Diagnosis is done on the first visit. Valve replacement may require sourcing and a follow-up depending on the model.
- Diagnostic visit typically completed within an hour
- TXV cleaning can sometimes be done on the same visit
- EEV replacement may need a follow-up for part sourcing
- We confirm timing once the valve type and model are identified
What we check
Valve faults overlap with gas charge and airflow issues. We check each variable to isolate the cause before opening the refrigerant circuit.
- Suction and discharge pressure under load
- Superheat and subcooling readings
- Valve body temperature compared to evaporator
- EEV coil signal and PCB output for electronic valves
- Filter drier condition — a clogged drier can mimic valve restriction
- Refrigerant charge level to rule out undercharge
Common expansion valve faults
These are the valve-related faults we see most often in residential split systems.
- Stuck closed — no refrigerant enters the evaporator, no cooling at all
- Stuck open — evaporator floods with liquid, ice builds up on the coil
- Partial blockage — uneven cooling, warm spots on the evaporator
- EEV motor failure — valve does not respond to PCB commands
- Sensing bulb detached (TXV) — valve cannot read evaporator temperature
- Debris clogging — contamination from a previous repair or compressor failure
When valve replacement may not be worth it
The valve itself is not the most expensive part, but the labour to access it and the system recharge add up. For older units, the total cost matters.
- Unit is old and other components are showing wear
- Previous compressor failure may have sent debris into the valve
- Refrigerant type is being phased out and recharge cost is rising
- Multiple faults found alongside the valve issue
What customers say
Highly professional and efficient service! The technicians arrived on time, performed a thorough cleaning, and fixed my aircon issue. Honest pricing, no hidden charges.
I
Irwan Abu Samah
Initially engaged another company to look into the issue with our aircon but was quoted a much higher price. Snowflake clearly explained the issue and what needs to be done, and recommended possible solutions based on their expertise.
R
Rafidah B
Snowflake clearly explained the cause of the issue and what needs to be done, recommended possible solutions based on what is best for the customer.
S
SaifudinDxdin
Expansion valve repair FAQ
Related reading
Unit freezing up or not cooling properly?
Describe what the unit is doing and we will confirm whether a diagnostic visit is the right next step.
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