A solar monitor is located on the side of the solar control unit and houses a green and a red LED.
The green LED, marked "Solar", indicates the current operational mode of the solar water heater and the red LED, marked "Attention", indicates a fault mode.
The green LED will emit either a constant glow or a series of flashes, with a 2 second interval between each series.
The red LED will emit a series of flashes, with a 2 second interval between each series, only if there is a particular fault condition with the system.
If the power supply to the solar control unit is on and the green LED is off or the red LED is flashing, this indicates there may be a fault with the water heater. The red LED may emit up to six flashes in each series of flashes.
 If the system is in standby mode with the green LED emitting either a constant glow or slow pulsing flashes (circulator is off) and the solar storage tank is full of hot water, the red LED may simultaneously emit a constant glow if solar radiation is still being received by the solar collectors. This does not indicate a fault. The red LED will go out when the temperature in the solar collectors decreases.
 During periods of high solar radiation and the circulator activates after having been off (the green LED will emit either a rapid pulse or a series of three flashes), it is possible the red LED may simultaneously emit a rapid pulse for a period of up to ten (10) minutes. This does not indicate a fault.
If the red LED continues to emit a rapid pulse for longer than ten (10) minutes, or emits a series of flashes, then count the number of flashes and phone Rheem Service or their nearest Accredited Service Agent to arrange for an inspection.