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Samsung Air Conditioner Error Code E198

Error due to disconnected thermal fuse of indoor unit.

Samsung codesSamsung air conditioner codes

Error due to disconnected thermal fuse of indoor unit.

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What E198 means on a Samsung air conditioner

Samsung air conditioner error code E198 indicates that the indoor unit's thermal fuse has opened or become electrically disconnected from the control circuit. The thermal fuse is a one-time safety device installed on the indoor unit's heat exchanger or blower assembly. Its purpose is to interrupt the circuit if internal temperatures exceed a safe threshold, preventing overheating damage to the unit or a potential fire hazard. When the control board detects an open circuit at the thermal fuse terminals, it triggers E198 and shuts down operation.

Thermal fuses open for two primary reasons: the fuse has blown due to an actual overtemperature event, or the electrical connection between the fuse and the control board has been lost. A blown fuse is a permanent, non-resettable failure and requires physical replacement. A connection fault can be caused by a corroded terminal, a loose wiring harness plug, or damaged lead wires. Identifying which scenario applies is critical before ordering parts, because replacing the fuse without addressing the root cause of overheating will result in repeated failures.

Common contributors to overheating that can trigger the thermal fuse include severely restricted airflow from a clogged air filter or blocked return grille, a frozen evaporator coil, a malfunctioning indoor blower motor, or low refrigerant charge causing abnormal coil temperatures. Technicians should inspect the entire indoor air path and motor operation before condemning only the fuse itself.

Source: manufacturer service documentation.

Common causes of E198

  1. 01

    Blown thermal fuse

    Part replacement

    The thermal fuse has permanently opened due to an overtemperature condition. A simple continuity test with a multimeter will confirm this: a healthy fuse reads near zero ohms, while a blown fuse reads infinite resistance (open circuit). Replacement is required.

  2. 02

    Loose or disconnected wiring harness

    Wiring / connection

    The connector or lead wires between the thermal fuse and the indoor control board may have come loose, corroded, or broken, causing a false open-circuit reading. Inspect all wiring connections at the fuse terminals and the board header for secure seating and corrosion.

  3. 03

    Restricted airflow causing overheating

    Wiring / connection

    A heavily clogged air filter, blocked return grille, or closed supply vents can reduce airflow enough to cause the indoor unit to overheat and trip the thermal fuse. Check and clean all filters and verify unobstructed airflow before replacing the fuse.

  4. 04

    Faulty indoor blower motor

    Part replacement

    If the blower motor runs slowly or not at all, heat builds up around the evaporator and heat exchanger assembly, which can push temperatures high enough to open the thermal fuse. Test motor operation and check for unusual noise or sluggish rotation.

  5. 05

    Refrigerant charge issue

    Part replacement

    Incorrect refrigerant charge, particularly an overcharge, can cause abnormal coil temperatures that contribute to internal overheating events. This condition requires gauges and should be evaluated by a certified HVAC technician.

See the test procedure for each cause

Frequently asked questions about E198

What does E198 mean on a Samsung air conditioner?
E198 means the indoor unit's thermal fuse circuit is open, either because the fuse has blown or because its electrical connection has been lost. The thermal fuse is a safety component that permanently interrupts the circuit if the unit overheats. The air conditioner will not operate normally until the fuse is tested and the fault is resolved.
Can I fix E198 myself, or do I need a technician?
Some steps are accessible to a knowledgeable DIYer, such as checking and cleaning clogged air filters or inspecting visible wiring connections for loose plugs. However, testing and replacing the thermal fuse requires opening the indoor unit and using a multimeter to check continuity, which carries some risk if not done carefully. Any diagnosis involving refrigerant charge requires a licensed HVAC technician.
Is it safe to keep running the air conditioner when E198 is displayed?
No. The E198 code typically causes the unit to shut itself down as a safety measure, and you should not attempt to force it to operate. The thermal fuse exists to prevent overheating damage or fire, so bypassing or ignoring this error is not safe. Have the unit inspected before resuming normal use.
Will resetting the air conditioner clear the E198 error?
A power reset may temporarily clear the error code from the display, but it will not fix the underlying problem. If the thermal fuse has blown, it is a non-resettable component and must be physically replaced. If the fault is a loose wiring connection, a reset will not secure that connection, and the error will return quickly.
How much does it cost to repair a Samsung air conditioner showing E198?
If only the thermal fuse needs replacement, parts costs are typically low, often in the range of a few dollars to around $20 for the fuse itself. Labor for an HVAC technician to diagnose, access the indoor unit, and replace the fuse generally adds $75 to $200 or more depending on your location and the complexity of the unit. If the root cause involves a faulty blower motor or a refrigerant issue, total repair costs can rise to $150 to $500 or higher.

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