I'm assuming you're referring to a gas burner that supplements the heat pump. If the burner lights at all, The ignition system is working. If you need to reset it for it to relight, I would suspect the thermocouple. It detects the flame to prevent gas from pouring out of an unlit burner. If it malfunctions, the control thinks the burner didn't light and shuts down for safety.
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I'm assuming you're referring to a gas burner that supplements the heat pump. If the burner lights at all, The ignition system is working. If you need to reset it for it to relight, I would suspect the thermocouple. It detects the flame to prevent gas from pouring out of an unlit burner. If it malfunctions, the control thinks the burner didn't light and shuts down for safety.