Hayward H400FD displays LO fault code at display. Pump water pressure is same as has been in past with heater operational. Heater intalled approx. 2 months ago. Hear what appears to be sound of relays closing 2-3 times when turn on before LO fault code appears. PLEASE do not provide Service Manual information; I have already assessed
Pool & Spa - Hayward - H Series Pool & Spa Heater 400k Btu Propane Gas Milivolt...
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If the heater is connected to the line side of the circuit it will be powered at all times. In this situation, when the pump shuts down the heater will display a fault code of “LO”. If there is a call for heat and the pump then restarts there will be a 2-minute delay for the heater to fire. After the pump has been running for at least 2 minutes there is no delay for heater operation. Wiring the heater to the load side of the timer or controller will not result in a 2-minute delay if the pump primes quickly enough to activate the heater’s water pressure switch. If the pump is slow to prime the heater may display an “LO” fault code and will take 2 minutes to automatically restart. If the pump has primed, this wait can be avoided by manually clearing the error code via the keypad by changing the mode through the “STANDBy” setting and returning to the initial setting (“SPA” or “POOL”). When a heater is wired to the line side of the power circuit (continuous power) the blower will not operate when the pump is cycled via a time clock or other switch method..
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Pump runs continuously (i.e., already primed) when turn on heater. Water pressure is same as past 2 months, since initial / successful heater installation. Just today, LO fault code appeared when trying to start heater. Have cycled power (pump still running) at display and via breaker. LO fault still present.