Rheem Water Heater - Manual (Page 33)

INSTALLATION – SOLAR COLLECTORS
33
PIPE LENGTHS
The solar hot and solar cold pipes between the solar storage tank and the solar
collectors shall:
• be of DN15 hard drawn copper pipe.
• have a continuous fall from the solar collectors to the solar storage tank of a
minimum 5
° (1 in 10 grade).
• not exceed the maximum recommended lengths as specified in the table.
Maximum recommended total combined pipe length (solar cold + solar hot)
and number of 90 ° bends
1 or 2 Collectors 3 Collectors
Pipe Size
Pipe Length 90 ° Bends Pipe Length 90 ° Bends
DN15 40 metres 20 30 metres 20
For each additional 90 ° bend, reduce the maximum total pipe length by 0.5 metres.
For each additional metre of pipe length, reduce the number of 90 ° bends by two.
Note: One 90 ° elbow is equal to two 90° bends.
Notes:
• It is important not to cross connect the solar cold and solar hot pipes to the
incorrect connections.
• The solar cold pipe connects to the bottom of the solar collectors and the
solar hot pipe connects to the top of the solar collectors diagonally opposite
to the solar cold pipe connection.
• The hot sensor connection is at the top of the solar collector, directly above
the solar cold inlet connection.
• Refer to “Warning: Plumber – Be Aware” on page 35.
It is essential for these requirements to be followed for the system to operate
correctly and efficiently. Solar pipe work which is oversized, or does not have
the correct fall, or is too long can result in the drain back system not operating
effectively.