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How to troubleshoot 0018 AC contactor open on a GT250?

Inverter faulted on 0018, AC contactor open fault.

Product Line:


The thermal switches TS1\TS2 or TS3\TS4 are open. 48VDC power supply, SSR1\SSR2, AC contactor or its' coil, AC and DC aux contactor, CCU board, In-rush circuit issue

Note: The work instruction provided is meant for those who are qualified to work on the inverter. This means that they should know how to properly Lock out and Tag Out (LOTO) the inverter...,etc.

Assuming the 48VDC power supply and its' fuses are good. Check the Thermal switches TS1, TS2, TS3 and TS4 and make sure they are not open. Check connectivity on the solid state relays (SSR1 and SSR2.) If the connection is good and you have the SSRs, replace both SSR1 and SSR2. If that does not fix the issue, replace the CCU board.

The last thing to check is the fuses on the in-rush board. If any of these are blown, it will cause the fault0018.
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