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Solar Pool Heating System -- Installation & User Manual
© Copyright 2020 Optex Solar Pty Ltd. All rights strictly reserved.
Page 50
26
Drain-Down, Frost Proofing and Winterization
26.1
Drain Down
All pool heating systems have a drain down design and MUST drain as fully as possible when the system stops.
26.2
Winterization
Please note, while your potable HPDE/Silicon collector array does not require regular winter flushing,
your solar
booster pump may require winter flushing
. If this is the case and you do not want to run your system over winter
you can winterize your system by draining the solar side of the system, disconnecting the solar booster pump and
flushing the pump with clean water for storage over winter.
26.3
Installing a By-Pass Tube or By-Pass Ball Valve (18)
A drain tube (or a by-pass ball valve with 6mm hole) can be used to drain non-self draining sections of PVC piping in
frost prone areas. In some cases where there are issues with pump priming and a perfectly sealing non-return valve
(8) is required; the aforementioned by-pass lines can be installed on the supply and return solar lines leading up to
the roof approximately one metre above pump level to reduce priming pressure. Please request this component if
you require it.
To install, drill into the PVC pipe using an 8.5mm drill.
Note: PVC plastic should be
preheated to 5
0˚C using a heat gun
or it may split when drilling.
Insert the rubber
grommet into the hole first, and then insert the single barb side barb into the
grommet. Finally, connect the by-pass tube to the double barb side barb ends.
The use of a water tight
non-return valve on the solar supply will prevent drain down
which could result in water freezing inside PVC piping in frost prone areas and/or hot
water stagnation in summer.
Any non-return valves installed on the supply line MUST
have a 6mm drain hole drilled in the flap to allow drain down.
Why?
The main purpose
of the non-return valve is to prevent a large volume of water from spinning the pumps
rotor backwards when the pump stops. A 6mm hole allows slow drain down while also
preventing hammer action in the flap when the pump stops.
PVC piping should be installed with a slope such that all water drains out of the piping to
when the pump stops to ensure a freeze proof system. There should be no U-bend water
traps - these can freeze over and burst plumbing lines in the winter. Note: PE lines are not
affected as these are frost impervious.
Independent systems with a drain tube anywhere in the
system MUST be installed with a fine (<0.5mm) strainer,
or else this tube may get blocked up.
