Error codes › Water Heater — Tankless › Truma AquaGo (comfort plus) › W21 (flash: 3s,1l,1s,1l,1s,1l)
Truma AquaGo (comfort plus) error code W21 (flash: 3s,1l,1s,1l,1s,1l)
WCT (circulation line temp sensor) — short, open, unplugged, OR colder than 14 °F (-10 °C)
What to check, and in what order, is in the app. The flow Truma AquaGo — error code / symptom diagnostic (DLE60B / DLE60C / DLE60CP) walks this code step by step with the pass/fail measurements, wiring schematics and procedures that go with it, and it works offline in the bay.
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- Truma_AquaGo_Basic_Comfort_ComfortPlus_Operating_Installation_Instructions.txt
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