Lennox Split & Multi-Split

Lennox Error Code E436

Split & Multi-Split

E436 means different things on different Split & Multi-Split models. Enter your model number to see only your reading, or find your model below.

What It Means

  • Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then reapply power.
  • Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, the Unitary Control will cycle the contactor to prevent the unit from locking out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.
  • Inverter heat sink temperature exceeded limit during compressor operation. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, unit will cycle off if heat sink temperature exceeds 185F, during compressor operation along with a E441 compressor slow down message. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

Causes & actions from Lennox

Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then reapply power.

25 models

EL18XCV, EL18XCV-024, EL18XCV-036, EL18XCV-048, EL18XCV-060, EL18XPV, EL18XPV-024, EL18XPV-036, EL18XPV-048, EL18XPV-060, EL22KCV, EL22KCV-024, EL22KCV-036, EL22KCV-048, EL22KCV-060, SL25KCV, SL25KCV-024, SL25KCV-036, SL25KCV-048, SL25KCV-060, SL28XCV, SL28XCV-024, SL28XCV-036, SL28XCV-048, SL28XCV-060

Air conditioner (outdoor)

How it shows
  • Inverter code: 62
  • Inverter LED flash code: Red 6 flashes, Green 2 flashes (green: flashing ×2, red: flashing ×6)
  • Outdoor control 7-segment display: E436

Issue: Feedback from supplier tear down of inverter indicates that the screws that hold the inverter to the inverter board were loose causing poor contact between these two components. Corrective Action: Tighten screws that hold the heat sink to the inverter control board. NOTE: Wait five minutes to all capacitor to discharge before checking screws.

Other manual wording

EL18XCV, EL18XCV-024, EL18XCV-036, EL18XCV-048, EL18XCV-060, EL18XPV, EL18XPV-024, EL18XPV-036, EL18XPV-048, EL18XPV-060, EL22KCV,…

Issue: This error may occur if the outdoor fan fails to operate or the inverter heat sink is obstructed with debris. Feedback from supplier tear down of inverter indicates that the screws that hold the inverter to the inverter board were loose causing poor contact between these two components. Corrective Action: Tighten screws that hold the heat sink to the inverter control board. NOTE: Wait five minutes to allow capacitor to discharge before checking screws.

Applicable models & manual sources
  • EL18XCV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re- apply power.

    EL18XCV, EL18XCV-024, EL18XCV-036, EL18XCV-048, EL18XCV-060

    EL18XCV manual, page 78

    EL18XCV manual, page 78

  • EL18XPV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re- apply power.

    EL18XPV, EL18XPV-024, EL18XPV-036, EL18XPV-048, EL18XPV-060

    EL18XPV manual, page 81

    EL18XPV manual, page 81

  • EL22KCV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re- apply power.

    EL22KCV, EL22KCV-024, EL22KCV-036, EL22KCV-048, EL22KCV-060

    EL22KCV manual, page 78

  • SL25KCV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re- apply power.

    SL25KCV, SL25KCV-024, SL25KCV-036, SL25KCV-048, SL25KCV-060

    SL25KCV manual, page 73

    SL25KCV manual, page 73

  • SL28XCV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re- apply power.

    SL28XCV, SL28XCV-024, SL28XCV-036, SL28XCV-048, SL28XCV-060

    SL28XCV manual, page 67

  • EL18XCV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    EL18XCV, EL18XCV-024, EL18XCV-036, EL18XCV-048, EL18XCV-060

    EL18XCV manual, page 39

  • EL18XPV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    EL18XPV, EL18XPV-024, EL18XPV-036, EL18XPV-048, EL18XPV-060

    EL18XPV manual, page 39

  • EL22KCV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    EL22KCV, EL22KCV-024, EL22KCV-036, EL22KCV-048, EL22KCV-060

    EL22KCV manual, page 42

    EL22KCV manual, page 42

  • SL25KCV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    SL25KCV, SL25KCV-024, SL25KCV-036, SL25KCV-048, SL25KCV-060

    SL25KCV manual, page 39

    SL25KCV manual, page 39

  • SL28XCV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    SL28XCV, SL28XCV-024, SL28XCV-036, SL28XCV-048, SL28XCV-060

    SL28XCV manual, page 33

Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, the Unitary Control will cycle the contactor to prevent the unit from locking out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

15 models

EL19KPV, EL19KPV-024, EL19KPV-036, EL19KPV-048, EL19KPV-060, EL21KLV, EL21KLV-024, EL21KLV-036, EL21KLV-048, EL21KLV-060, SL22KLV, SL22KLV-024, SL22KLV-036, SL22KLV-048, SL22KLV-060

Heat pump (outdoor)

How it shows
  • Inverter code: 62
  • Inverter LED flash code: Red 6 flashes, Green 2 flashes (green: flashing ×2, red: flashing ×6)
  • Outdoor control 7-segment display: E436

Issue: Feedback from supplier tear down of inverter indicates that the screws that hold the inverter to the inverter board were loose causing poor contact between these two components. Corrective Action: Tighten screws that hold the heat sink to the inverter control board. NOTE: Wait five minutes to all capacitor to discharge before checking screws.

Other manual wording (1 of 2)

EL19KPV, EL19KPV-024, EL19KPV-036, EL19KPV-048, EL19KPV-060, EL21KLV, EL21KLV-024, EL21KLV-036, EL21KLV-048, EL21KLV-060

Issue: This error may occur if the outdoor fan fails to operate or the inverter heat sink is obstructed with debris. Feedback from supplier tear down of inverter indicates that the screws that hold the inverter to the inverter board were loose causing poor contact between these two components. Corrective Action: Tighten screws that hold the heat sink to the inverter control board. NOTE: Wait five minutes to allow capacitor to discharge before checking screws.

Other manual wording (2 of 2)

EL21KLV, EL21KLV-024, EL21KLV-036, EL21KLV-048, EL21KLV-060

The inverter finned aluminum heat sink is located on the back side of the inverter in the condenser air stream. If this alert code occurs frequently, especially at lower outdoor temperatures, check the heat sink for debris that may reduce heat transfer or possible obstructions that may impact air flow across the heat sink. Alert code 436 may also occur if the unit is operating at high pressures.

Applicable models & manual sources
  • EL19KPV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, the unitary control will cycle the contactor to prevent the unit from locking out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re- apply power.

    EL19KPV, EL19KPV-024, EL19KPV-036, EL19KPV-048, EL19KPV-060

    EL19KPV manual, page 83

    EL19KPV manual, page 83

  • SL22KLV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, the unitary control will cycle the contactor to prevent the unit from locking out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re- apply power.

    SL22KLV, SL22KLV-024, SL22KLV-036, SL22KLV-048, SL22KLV-060

    SL22KLV manual, page 89

  • EL19KPV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, the unitary control will cycle the contactor to prevent the unit from locking out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    EL19KPV, EL19KPV-024, EL19KPV-036, EL19KPV-048, EL19KPV-060

    EL19KPV manual, page 45

    EL19KPV manual, page 45

  • EL21KLV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, the Unitary Control will cycle the contactor to prevent the unit from locking out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    EL21KLV, EL21KLV-024, EL21KLV-036, EL21KLV-048, EL21KLV-060

    EL21KLV manual, page 48

  • EL21KLV

    Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, the Unitary Control will cycle the contactor to prevent the unit from locking out. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    EL21KLV, EL21KLV-024, EL21KLV-036, EL21KLV-048, EL21KLV-060

    EL21KLV manual, page 95

Inverter heat sink temperature exceeded limit during compressor operation. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, unit will cycle off if heat sink temperature exceeds 185F, during compressor operation along with a E441 compressor slow down message. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

5 models

SL22KLV, SL22KLV-024, SL22KLV-036, SL22KLV-048, SL22KLV-060

Heat pump (outdoor)

How it shows
  • Inverter code: 62
  • Inverter LED flash code: Red 6 flashes, Green 2 flashes (green: flashing ×2, red: flashing ×6)
  • Outdoor control 7-segment display: E436

Issue: This error may occur if the outdoor fan fails to operate or the inverter heat sink is obstructed with debris. Feedback from supplier tear down of inverter indicates that the screws that hold the inverter to the inverter board were loose causing poor contact between these two components. Corrective Action: Tighten screws that hold the heat sink to the inverter control board. NOTE: Wait five minutes to allow capacitor to discharge before checking screws.

Applicable models & manual sources
  • SL22KLV

    Inverter heat sink temperature exceeded limit during compressor operation. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, unit will cycle off if heat sink temperature exceeds 185F, during compressor operation along with a E441 compressor slow down message. To clear, disconnect power to the indoor unit (24VAC power source to the outdoor control) which will power off the outdoor control and will open the outdoor unit contactor, which interrupts power to the inverter and then re-apply power.

    SL22KLV, SL22KLV-024, SL22KLV-036, SL22KLV-048, SL22KLV-060

    SL22KLV manual, page 45

Disclaimer: This information is for general reference. Code wording and instructions vary by model. Always follow the service manual for your exact unit.

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