E20
Multiquip ATS Communication / Start Signal Fault

Controller displays E20, generator will not start in AUTO when utility fails

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Open start signal wiring between ATS and generator, Incorrect ATS control wiring, Faulty ATS start relay, Controller input configuration error

How to Fix / Troubleshooting

Safety first: De‑energize control circuits before working on ATS wiring. Only qualified personnel should open ATS enclosures.

  • Step 1 – Verify manual start: Confirm that the generator starts and runs normally in MANUAL mode. If so, the issue is likely in the ATS start circuit.
  • Step 2 – Check start signal terminals: Locate the remote start input terminals on the Multiquip controller and the corresponding contacts in the ATS. Verify continuity of the wiring between them.
  • Step 3 – Test ATS start relay: Simulate a utility failure and measure voltage or continuity at the ATS start contacts. If they do not close, the ATS control board or relay may be faulty.
  • Step 4 – Confirm controller input settings: In the controller menu, verify that the remote start input is enabled and configured for the correct type (dry contact vs. voltage input).
  • Step 5 – Clear code and simulate outage: After repairing wiring or ATS components, clear E20 and perform a full functional test by simulating a power outage.
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Repair Difficulty

Hard 4/5

Required Part

Automatic Transfer Switch Start Relay
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