Technical data

INSTALLATION – SOLAR COLLECTORS

PIPE LENGTHS

The solar hot and solar cold pipes between the solar storage tank and the solar collectors shall:

 be of DN15 bendable grade or hard drawn copper tube.

Annealed or soft copper shall not be used.

 have a continuous fall from the solar collectors to the solar storage tank of a minimum 5° (1 in 10 grade)

and be of a design to enable complete drain back of the closed circuit fluid.

Care must be taken to ensure the pipe work maintains a continuous fall over the life of the installation.

Pipe work should be fixed at regular intervals to assist in maintaining this requirement.

 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

Pipe Size

1 or 2 Collectors

3 Collectors

Pipe Length

90° Bends

Pipe Length

90° Bends

DN15

40 metres

30 metres

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 to connect the solar cold and solar hot pipes to the correct connections at the solar collector

and at the solar storage tank.

 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 lowest corner of the solar collector installation, which is where the solar cold pipe connects to the

collector array, should be the corner closest to the solar storage tank. This will maximise the gradient for

the continuous fall of the solar cold pipe, by providing a shorter horizontal run of pipe work for the vertical

fall.

 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 31.

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.