Raypak B0147 Owner's Manual And Installation Instructions page 8

HOW YOUR WATER HEATER WORKS
BURNER IGNITION
147 Hi/Lo Models
The water heater utilises an automatic burner ignition system, which lights the main burner gas when the
thermostat registers a need for heating.
A hot surface igniter (HSI) heats up when there is a call for heating. When the HSI probe is up to temperature, a
valve opens allowing gas to the main burner and this is ignited by the HSI probe. Provided successful ignition of the
main burner flame is detected, the valve remains open to supply gas to the main burner. If the main burner fails to
ignite the ignition system will lock out.
147 On/Off Models
The water heater utilises an automatic burner ignition system, incorporating an automatic pilot burner, which lights
the main burner gas when the thermostat registers a need for heating.
A hot surface igniter (HSI) heats up when there is a call for heating. When the HSI probe is up to temperature, a
valve opens allowing gas to the pilot burner and this is ignited by the HSI probe. When successful ignition of the
pilot flame is detected, the valves open to supply gas to the main burner. If the pilot fails to ignite after two
attempts, the ignition system will lock out.
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