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Error code reference

Maytag Microwave Error Code Err8

Over temperature condition detected.

Maytag codesMaytag microwave codes

Over temperature condition detected.

First step from the service manual

Press STOP/RESET twice; check Triac TR2, check that Relay K3 is cycling (Convection HTR), check Thermal Limiter.

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

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What Err8 means on a Maytag microwave

Err8 on a Maytag microwave indicates that an over temperature condition has been detected within the appliance. This code is triggered when internal temperatures exceed safe operating thresholds, typically monitored by a thermal limiter and associated control circuitry. The convection heating system is the primary suspect, as the error specifically points to Triac TR2 and Relay K3, which are the control components responsible for switching the convection heater circuit on and off during operation.

Triac TR2 is a semiconductor switching device that controls power delivery to the convection heater. If TR2 shorts or fails in a partially conducting state, it can allow uncontrolled current flow to the heater, causing temperatures to rise beyond normal limits. Relay K3, which cycles the convection heater on and off as part of normal operation, may also be stuck in a closed position, preventing the heater from shutting down at the appropriate time. Either of these faults results in sustained or excessive heat buildup inside the cavity.

The thermal limiter acts as a safety cutoff device designed to open the circuit when temperatures reach a critical level. If the limiter has already tripped or failed open due to repeated overheating events, it must be tested for continuity and replaced if defective. Because this code involves high-voltage components and active heating elements, diagnosis should proceed methodically starting with a full reset before moving on to component-level testing of TR2, K3, and the thermal limiter.

Source: manufacturer service documentation.

Common causes of Err8

  1. 01

    Relay K3 Stuck Closed

    Part replacement

    If Relay K3 is not cycling properly and remains closed, the convection heater runs continuously without shutting off, causing temperatures to spike. Confirm the relay is opening and closing during a convection cycle by listening for audible clicks and testing coil and contact continuity.

  2. 02

    Shorted or Failing Triac TR2

    Part replacement

    Triac TR2 controls power to the convection heater, and a shorted triac can allow the heater to run even when the control board sends a shutoff signal. Testing TR2 with a multimeter for resistance across its terminals can reveal a short circuit condition.

  3. 03

    Tripped or Failed Thermal Limiter

    Part replacement

    The thermal limiter is a one-time or resettable safety device that opens when temperatures exceed a set threshold. A limiter that has blown open due to an overtemperature event will need to be tested for continuity and replaced before the unit will operate normally.

  4. 04

    Blocked or Restricted Ventilation

    Wiring / connection

    Insufficient airflow around or through the microwave can cause internal heat to accumulate and trigger the over temperature sensor. Check that all vents are clear of obstructions and that the unit has adequate clearance on all sides.

  5. 05

    Control Board Fault

    Part replacement

    If TR2 and K3 test within specification and the thermal limiter is intact, the control board itself may be sending incorrect signals that prevent proper heater cycling. A faulty board can cause erratic switching behavior that results in overheating.

See the test procedure for each cause

Frequently asked questions about Err8

What does Err8 mean on a Maytag microwave?
Err8 indicates that the microwave has detected an over temperature condition inside the appliance. The error specifically involves the convection heating circuit, including Triac TR2 and Relay K3, which control the convection heater. A thermal limiter is also part of the safety system that monitors and responds to excessive heat. This code is a protective shutdown to prevent component damage or a fire hazard.
Will pressing STOP/RESET clear the Err8 code on my Maytag microwave?
Pressing STOP/RESET twice is the recommended first step and may clear the code if the overtemperature event was temporary, such as a ventilation issue that has since resolved. However, if the underlying cause is a failed Triac TR2, a stuck Relay K3, or a blown thermal limiter, the error will return as soon as the unit attempts to run the convection heater again. A reset alone is not a repair.
Is it safe to use my Maytag microwave while it is showing Err8?
No, you should not continue using the microwave while Err8 is active. This code indicates a potentially dangerous overtemperature condition tied to the convection heating system. Using the appliance with a shorted triac or a stuck relay could cause further component damage or create a fire risk. The unit should remain unplugged until the fault is properly diagnosed and repaired.
How do I fix Err8 on a Maytag microwave?
Start by pressing STOP/RESET twice to attempt a reset. If the code returns, the repair process involves testing Relay K3 to confirm it is cycling correctly, checking Triac TR2 for a short circuit condition, and testing the thermal limiter for continuity. Any component that fails testing will need to be replaced. Because this diagnosis involves the high-voltage convection heater circuit, it is recommended for technicians or experienced DIYers who understand appliance electrical safety procedures.
How much does it cost to repair an Err8 error on a Maytag microwave?
Repair costs vary depending on which component has failed. A thermal limiter replacement is generally the least expensive repair, typically in the range of $50 to $150 including parts and labor. Replacing Relay K3 or Triac TR2 falls in a similar or slightly higher range. If the control board is the root cause, costs can rise to $150 to $350 or more depending on parts availability and labor rates in your area.

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