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Error code reference

Amana Furnace Error Code 6 Flashes

Reversed polarity

Amana codesAmana furnace codes

Reversed polarity - 115V or 24V AC power leads are reversed (50A55/HSI-2/50M61/50V61 controls only).

First step from the service manual

Review wiring diagram; verify proper grounding; check and correct wiring.

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

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What 6 Flashes means on a Amana furnace

The 6 Flashes error code on an Amana furnace indicates a reversed polarity condition in either the 115V AC line voltage circuit or the 24V AC low-voltage control circuit. This fault applies specifically to furnaces equipped with 50A55, HSI-2, 50M61, or 50V61 ignition control boards. These control boards monitor the polarity of incoming power as part of their self-diagnostic routines. When the board detects that the hot and neutral conductors are swapped, or that the 24V transformer secondary leads are wired incorrectly, it locks out and signals the fault via the 6-flash LED sequence.

Polarity matters in these systems because the control board uses the neutral as a reference point for flame sensing. The flame sensor (rod) works by measuring microamp-level ionization current through the burner flame, and this measurement depends on correct polarity to establish the proper current path to ground. If polarity is reversed, the flame sensing circuit cannot function correctly, which can prevent the furnace from proving flame even when ignition is successful.

The most common source of this fault is incorrect wiring at the furnace junction box, either from a previous repair or an original installation error. It can also result from a reversed 24V transformer secondary connection at the control board terminals. Proper diagnosis requires consulting the wiring diagram for the specific unit, verifying that the hot leg connects to the correct terminal, and confirming that the furnace cabinet is properly grounded to the neutral conductor at the panel.

Source: manufacturer service documentation.

Common causes of 6 Flashes

  1. 01

    Reversed 115V line voltage wiring at junction box

    Wiring / connection

    The hot and neutral conductors feeding the furnace are swapped at the line voltage junction box or disconnect. This often happens after a recent electrical repair or installation. Use a voltmeter to verify the hot leg is connected to the correct terminal as shown on the wiring diagram.

  2. 02

    Reversed 24V transformer secondary leads

    Wiring / connection

    The low-voltage transformer secondary wires connected to the control board terminals may be swapped. Check that the R and C terminals receive the correct polarity from the transformer secondary, referencing the unit wiring diagram.

  3. 03

    Improper or missing furnace ground

    Wiring / connection

    A missing or poorly connected equipment ground can cause the control board to detect an apparent polarity fault, since grounding is part of the polarity reference circuit. Verify that the furnace cabinet is properly bonded to the electrical panel ground.

  4. 04

    Previous wiring repair performed incorrectly

    Wiring / connection

    A prior service call or DIY repair may have reconnected wires without following the wiring diagram, resulting in reversed polarity at either voltage level. Review all recently disturbed wiring connections against the diagram affixed to the furnace cabinet.

  5. 05

    Faulty or failed control board

    Part replacement

    In rare cases, an internal fault on the 50A55, HSI-2, 50M61, or 50V61 control board causes it to incorrectly report a polarity fault even when wiring is correct. This should only be suspected after all wiring and grounding have been confirmed correct.

See the test procedure for each cause

Frequently asked questions about 6 Flashes

What does 6 Flashes mean on a Amana furnace?
The 6 Flashes code on an Amana furnace indicates reversed polarity in either the 115V AC supply wiring or the 24V AC control circuit wiring. This fault applies only to units with 50A55, HSI-2, 50M61, or 50V61 control boards. The furnace will lock out and not operate until the polarity issue is corrected. Resolving it requires inspecting and correcting the wiring according to the furnace wiring diagram.
How do I fix a 6 Flashes error on my Amana furnace?
Start by turning off power to the furnace and locating the wiring diagram on the unit cabinet. Check that the 115V hot and neutral conductors are connected to the correct terminals at the junction box, and verify that the 24V transformer secondary leads are not swapped at the control board. Also confirm the furnace is properly grounded. If you are not comfortable working with electrical wiring, contact a licensed HVAC technician.
Is a 6 Flashes polarity error on an Amana furnace dangerous?
Yes, reversed polarity is a serious electrical condition that should be corrected promptly. Reversed line voltage polarity can create shock hazards and may damage the control board or other components over time. The furnace is designed to lock out under this condition specifically to prevent unsafe operation. Do not attempt to bypass the fault or operate the furnace until the wiring has been properly corrected.
Will resetting my Amana furnace clear the 6 Flashes error?
Resetting the furnace by cycling the power will temporarily clear the fault display, but the error will return immediately if the underlying wiring problem has not been corrected. The control board checks polarity each time the unit powers up. A lasting fix requires identifying and correcting the reversed wiring connection before the furnace will operate normally.
How much does it cost to fix a reversed polarity fault on an Amana furnace?
If the fix is simply correcting a reversed wire connection, the cost is primarily the technician's diagnostic and labor time, typically in the range of $75 to $200 depending on local rates. If the control board was damaged by the polarity reversal and needs replacement, parts and labor costs can range from $250 to $600 or more. Getting a diagnosis first will clarify exactly what work is needed.

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