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Error code reference

Samsung Air Conditioner Error Code E175

More than 2 indoor units cool and heat simultaneously (mixed operation error).

Samsung codesSamsung air conditioner codes

More than 2 indoor units cool and heat simultaneously (mixed operation error).

First step from the service manual

Check another indoor unit operation mode.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What E175 means on a Samsung air conditioner

Error code E175 on a Samsung multi-zone air conditioning system indicates that more than two indoor units within the same refrigerant circuit are simultaneously operating in conflicting modes, specifically some units calling for cooling while others call for heating at the same time. This is referred to as a mixed operation error. In a heat pump based multi-split system, the refrigerant cycle can only run in one direction at a given time, either in cooling mode or heating mode. When the system detects that indoor units are demanding opposing modes concurrently, it triggers E175 to protect the system from attempting an impossible or damaging refrigerant cycle state.

The outdoor unit continuously monitors the operation mode signals being sent by all connected indoor units. When two or more units send conflicting mode requests simultaneously, the control board registers this as a mixed operation fault. The most common trigger is a user manually setting one indoor unit to cool and another to heat at the same time, which is not permitted in standard heat pump multi-split configurations. However, the error can also stem from a faulty indoor unit control board sending an incorrect mode signal, or a communication wiring issue causing a unit to broadcast a corrupted or unintended mode command.

Diagnosis should begin by checking the operation mode displayed on each indoor unit's controller or remote. Confirm that all active units are set to the same mode, either all cooling or all heating. If the settings appear consistent but the error persists, inspect the inter-unit communication wiring and the control boards of each indoor unit for faults.

Source: manufacturer service documentation.

Common causes of E175

  1. 01

    Conflicting mode settings across indoor units

    Wiring / connection

    A user has manually set one or more indoor units to cooling mode while others are set to heating mode. Check the mode setting on each indoor unit remote or wall controller and ensure they all match.

  2. 02

    Faulty indoor unit control board sending incorrect mode signal

    Part replacement

    A defective indoor unit PCB can transmit a corrupted or incorrect operation mode command to the outdoor unit, causing a perceived mixed operation conflict even when all remotes appear to be set correctly. Replacing the faulty board resolves this.

  3. 03

    Communication wiring fault between indoor and outdoor units

    Wiring / connection

    Damaged, shorted, or improperly connected communication cables can cause an indoor unit to send unintended mode signals. Inspect the inter-unit communication wiring for visible damage, loose terminals, or incorrect connections.

  4. 04

    Indoor unit firmware or software glitch

    Wiring / connection

    Occasionally a temporary software error in one indoor unit's controller can cause it to broadcast the wrong mode. Power cycling the affected unit may clear the condition, but recurring cases may require a firmware update or board replacement.

  5. 05

    Incorrect system configuration or zone assignment

    Wiring / connection

    If indoor units have been improperly configured during installation, such as incorrect address settings, the system may misinterpret mode assignments. Review the installation configuration and addressing of each indoor unit against system requirements.

See the test procedure for each cause

Frequently asked questions about E175

What does E175 mean on a Samsung air_conditioner?
E175 indicates a mixed operation error in which more than two indoor units within the same Samsung multi-zone system are simultaneously requesting conflicting modes, some cooling and some heating at the same time. Because the system refrigerant circuit can only operate in one direction at a time, it cannot satisfy both demands and shuts down with this fault code. The error protects the system from attempting an impossible operating state that could damage compressor components.
How do I fix error E175 on my Samsung air conditioner?
Start by checking the operation mode set on every indoor unit in the system and confirm they are all set to the same mode, either all cooling or all heating. If the settings look consistent, power cycle all units and restart them in a unified mode. If the error returns, inspect the communication wiring between units and consider testing or replacing the control board of any indoor unit that appears to be sending a conflicting signal.
Will resetting my Samsung air conditioner clear error E175?
A reset may temporarily clear E175 if the conflict was caused by a momentary glitch, but the error will return if the underlying cause is not resolved. If any indoor unit is still set to a different mode from the others after the reset, or if a faulty control board is sending the wrong signal, the fault will reappear. Address the root cause first before relying on a reset to clear the code.
Is error E175 on a Samsung air conditioner a safety concern?
E175 itself is a protective fault rather than an immediate safety hazard. The system stops operation to prevent the compressor and refrigerant circuit from being forced into a conflicting state that could cause mechanical damage over time. Continued attempts to run the system while ignoring this error could lead to compressor stress or premature component failure, so the issue should be resolved before resuming normal operation.
How much does it cost to repair error E175 on a Samsung air conditioner?
If the fix is simply correcting the mode settings on the indoor unit controllers, there is no parts cost and a technician visit fee may be the only expense, typically in the range of $75 to $150 for a service call. If a faulty indoor unit control board is the cause, board replacement parts generally range from $80 to $250 depending on the unit model, plus labor. Communication wiring repairs fall somewhere in between depending on the extent of the damage.

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