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Error code reference

Samsung Heat Pump Error Code P473

Indoor unit EEV open failure (1st detection)

Samsung codesSamsung heat pump codes
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What the P473 error code actually means

Your Samsung heat pump has detected that a valve inside one of your indoor units is not closing properly, allowing refrigerant to flow into a room unit that is supposed to be off. This can cause the overall system to work less efficiently and may lead to frost or reduced heating and cooling in other rooms. A technician will need to check the wiring and valve components inside the affected indoor unit to resolve this.

Diagnostic procedure

The full P473 procedure

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1
First diagnostic step
Check whether the EEV wire is connected to the indoor unit PCB correctly.
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Most common causes of P473

Ranked by how often they cause this code
  1. 1Loose or disconnected EEV wiring at the indoor PCB
  2. 2Faulty EEV stepper motor or coil
  3. 3EEV stuck open due to debris or mechanical failure
  4. 4Indoor unit PCB control fault
  5. 5Refrigerant system imbalance or overcharge

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Questions people ask about P473

What does P473 mean on a Samsung heat pump?
P473 indicates that the indoor unit's Electronic Expansion Valve has been detected in an open failure state for the first time. The valve is not closing properly, allowing refrigerant to flow into an indoor unit that is not actively running. This disrupts system pressures and can reduce efficiency across all zones. Prompt diagnosis is recommended to prevent further system impact.
Is it safe to keep running my heat pump with error P473 active?
Continuing to operate the system with P473 active is not recommended. Refrigerant migrating into a stopped indoor unit can cause liquid slugging at the compressor, frost buildup on the indoor coil, and pressure imbalances that stress other system components. It is best to shut down the affected zone or the full system until the fault is diagnosed and corrected.
Will resetting the heat pump clear the P473 error code?
A power reset may temporarily clear the P473 code since it is flagged as a first-detection event, but the fault will return if the underlying cause is not addressed. The EEV will continue to fail open if the wiring, valve, or PCB issue remains unresolved. Resetting without repair is not a long-term solution and can allow the problem to worsen.
Can I fix P473 myself or do I need a professional?
The first step, checking that the EEV wire harness is securely connected to the indoor PCB, is something a technically confident DIYer can inspect. However, if the wiring is intact and the valve or PCB needs to be tested or replaced, a certified HVAC technician is required, especially since refrigerant handling is involved and is regulated in most regions.
How much does it cost to repair a P473 error on a Samsung heat pump?
Repair costs depend on the root cause. A simple wiring fix may cost relatively little beyond a service call fee, typically in the range of $75 to $150 for diagnostics. If the EEV valve or its motor needs replacement, parts and labor can range from $200 to $600 or more depending on the unit and technician rates. PCB replacement would add further to that cost.

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