Rheem Drain Back Long Roof Sensor


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If you are just replacing the roof sensor on your system, we recommend you check the circulation pump. Just because the pump motor is running does not mean it is circulating water as it should and this will damage your new roof sensor. With some models of solar hot water systems, your best option may be replacing everything at once with a complete pump station. Please contact us if you have questions about this before you purchase this item.

Solar Hot Water Parts has the complete range of solar replacement spare parts. We are continually extending our solar hot water spare parts catalogue to give you the best selection of solar hot water replacement parts to choose from.

We sell the widest range of spare parts to suit any solar hot water service, whether it be a flat plate panel or evacuated tube solar collector. The Solar Hot Water Parts range is now online and ready to order, with complete tech specs to ensure your seamless selection.

If you're unsure which part suits, simply contact us -  click here



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.

The operational modes are:

Flashes Operational Modes

solid green (remains on) Standby mode

green slow pulse Standby mode (power on for less than 48 hours)

green rapid pulse Water circulating through collectors

3 x green Water circulating through collectors (power on for less than 48 hours)
no green (remains off) Power outage or call for service

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.