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Error code reference

Goodman Heat Pump Error Code EF

Auxiliary switch open.

Goodman codesGoodman heat pump codes

Auxiliary switch open.

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What EF means on a Goodman heat pump

The EF error code on a Goodman heat pump indicates that an auxiliary switch in the system has opened, interrupting a control circuit and triggering a fault condition. Auxiliary switches serve as secondary safety or interlock devices within the heat pump system. These switches monitor specific operating conditions such as refrigerant pressure, water flow, airflow, or other system parameters depending on the application and how the unit is configured. When one of these switches opens, it signals the control board that a boundary condition has been exceeded or that a required operating condition is no longer being met.

The most common auxiliary switches found in heat pump systems include high-pressure switches, low-pressure switches, flow switches (in water-source applications), and freeze protection switches. Any of these can be wired into the auxiliary switch input on the control board. When the switch opens due to an actual system fault or a component failure within the switch itself, the control board logs the EF code and may lock out heating or cooling operation to prevent equipment damage.

Diagnosing an EF code requires identifying which auxiliary switch is wired to the input and determining whether it has opened due to a genuine system condition such as low refrigerant charge, blocked airflow, or insufficient water flow, or due to a faulty switch. Technicians should check the switch with a multimeter for continuity, inspect field wiring for loose or corroded connections, and verify that the underlying system condition the switch monitors is within normal operating parameters before clearing the fault.

Source: manufacturer service documentation.

Common causes of EF

  1. 01

    Tripped high or low pressure switch

    Wiring / connection

    A refrigerant pressure switch may have opened due to low refrigerant charge, overcharge, or a blocked coil. Verify refrigerant pressures with gauges and inspect coils for dirt or obstruction.

  2. 02

    Faulty auxiliary switch

    Part replacement

    The switch itself may have failed in the open position even when system conditions are normal. Check continuity across the switch terminals with a multimeter to confirm whether the switch is defective.

  3. 03

    Loose or broken wiring at the auxiliary switch

    Wiring / connection

    Field wiring connections to the auxiliary switch input on the control board or at the switch terminals can become loose or corroded, causing an open circuit. Inspect all wiring connections for tightness and signs of corrosion.

  4. 04

    Insufficient airflow or blocked filter

    Part replacement

    If a freeze protection or airflow proving switch is wired to the auxiliary input, a dirty air filter or blocked return can cause it to open. Check and replace the air filter and clear any airflow obstructions.

  5. 05

    Low water flow (water-source applications)

    Wiring / connection

    On water-source heat pump configurations, a flow switch monitoring loop water flow can open if flow drops below the required threshold. Verify pump operation and check for blockages in the water loop.

See the test procedure for each cause

Frequently asked questions about EF

What does EF mean on a Goodman heat_pump?
The EF code on a Goodman heat pump means that an auxiliary switch in the system has opened, indicating a fault condition that has triggered the control board to interrupt normal operation. Auxiliary switches can include pressure switches, flow switches, or freeze protection devices depending on the system configuration. The unit will typically not operate normally until the underlying cause is identified and the fault is cleared.
Can I fix an EF code on my Goodman heat pump myself?
Some causes of the EF code, such as a clogged air filter restricting airflow, can be addressed by a homeowner. However, diagnosing a tripped pressure switch, checking refrigerant levels, or testing a faulty auxiliary switch requires tools and knowledge best suited to a certified HVAC technician. Attempting repairs involving refrigerant or internal wiring without proper training can be unsafe and may void warranties.
Is it safe to run my Goodman heat pump with an EF code?
It is not advisable to continue running the heat pump when an EF code is active. The auxiliary switch is a safety device designed to protect the equipment from operating under conditions that could cause damage. Running the unit while this fault is active could result in compressor damage or other costly failures.
Will resetting my Goodman heat pump clear the EF code?
Resetting the unit may temporarily clear the EF code, but if the underlying cause of the open auxiliary switch has not been resolved, the code will return. A reset does not fix the root problem. It is important to identify and correct the fault condition before relying on a reset to restore operation.
How much does it cost to repair an EF code on a Goodman heat pump?
Repair costs depend heavily on the root cause of the fault. Replacing a failed auxiliary switch is generally a lower-cost repair, typically ranging from $100 to $300 including labor. If the cause is low refrigerant requiring a leak search and recharge, costs can range from $300 to $700 or more. A diagnostic service call to identify the specific cause typically runs $75 to $150 before any parts or additional labor.

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