Aqua-Hot AHE-400-D02 error code WEBASTO BURNER PUMP PRESSURE LOW
Webasto burner fuel-pump output pressure is below the burner's 145 PSI preset, causing poor atomization, weak flame and a likely 'Burner Failed to Ignite' lockout downstream. A stuck check valve is a common Webasto failure mode. The pump (Webasto Fuel 10 Bar Pump Kit; burner WPX-909-180) is preset to 145 PSI and is field-adjustable per the service manual's fuel-pressure procedure.
What to check, and in what order, is in the app. The flow Webasto burner won't start (diesel indicator light off) 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 Heating Systems Service Manuals — aquahot.com
- Aqua-Hot Tech Support 800-685-4298 (Fort Lupton, CO)
- AquaHot 400 D02 Diesel Plus AC Hydronic Technician Service Diagnostic Reference (rv-tech-resources/54-aquahot-400-hydronic/AquaHot_400_D02_Diesel_Plus_AC_Hydronic_Technician_Service_Diagnostic_Reference.md)
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