!!
critical Keurig

Error Code 1

Brew Tank TCO is Open (no Heater on brew tank).

? What Causes This

Draining and forgetting to refill or Bad Triac.

How to Fix It

Refill the brew tank if it was drained. If the issue persists, contact your Keurig Authorized Distributor as the Triac may be faulty.

Source: page 16 of the official manual

From the manual

Manual page 16 — Keurig error 1

This error code appears in:

Keurig Coffee Maker