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Michelle LawrenceSep 13, 2025
What to do if my Hayward H400FDN Heater displays 'Blower Vacuum Switch closed'?
- MMaria HebertSep 13, 2025
If your Hayward Heater displays 'Blower Vacuum Switch closed', check the blower vacuum switch for issues.
What to do if my Hayward H400FDN Heater displays 'Blower Vacuum Switch closed'?
If your Hayward Heater displays 'Blower Vacuum Switch closed', check the blower vacuum switch for issues.
General| Type | Natural Gas |
|---|---|
| BTU Input | 400, 000 BTU |
| Pool Type | In-ground |
| Heat Exchanger | Cupro Nickel |
| Voltage | 120V |
| Efficiency | 84% |
| Water Flow Rate | 40-120 GPM |
| Inlet/Outlet Size | 2 in |
| Ignition | Electronic |
Essential safety information and warnings for operating the heater.
Describes the normal and failure-to-light operating sequences for the UHS heater.
Details on how to connect power and gas supply to the heater unit.
Step-by-step instructions for specific heater operations and adjustments.
List of diagnostic codes and associated replacement part numbers.
Step-by-step troubleshooting for common issues like no power, open fuses, and service LED codes.
Details on heat exchanger flow requirements, inspection, and failure causes.
Visual representations of the heater's electrical connections and components.
