Aqua-Hot AHE-250-D03 error code OVERHEAT TRIP
Boiler-coolant high-limit switch (215 deg F trip) opened, disabling the burner. The high-limit is manual-reset only. Indicates loss of heat dissipation from the boiler loop - usually a pump, zone-fan, flow, or coolant-level problem.
What to check, and in what order, is in the app. The flow Aqua-Hot — Fluid Level Check & Refill Procedure 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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- Aqua-Hot 200-Series 250P/250D Service ManualAqua-Hot
- Aqua-Hot Heating Systems Service Manuals — aquahot.com
- Aqua-Hot Tech Support 800-685-4298 (Fort Lupton, CO)
- AquaHot 250 D03 Diesel Hydronic Technician Service Diagnostic Reference (rv-tech-resources/53-aquahot-250-hydronic/AquaHot_250_D03_Diesel_Hydronic_Technician_Service_Diagnostic_Reference.md)
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