Aqua-Hot AHE-250-D03 error code COOLANT LEAK UNDER UNIT
Pink/red boiler antifreeze visible below the Aqua-Hot cabinet. Loss of coolant will eventually trigger overheat and may damage pump or boiler if ignored.
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.
Start free trial 14 days free, no card neededDocumented in
- 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)
Related codes
- OVERHEAT TRIPBoiler-coolant high-limit switch (215 deg F trip) opened, disabling…
- D1 LED OFFD1 is the Heating Status light (orange) on the relay control board …
- D4 LED NEVER ILLUMINATESOn the AHE-250 relay control board the indicator LEDs are D1 Heating…
- D5 LED OFF (OVERHEAT INDICATION)On the AHE-250 relay control board D5 = Burner Status (green) -- it…
- SMOKE OR SOOT AT EXHAUSTVisible black smoke or accumulating soot at the exhaust pipe…