Freeze Protection
If you are relying on the collectors naturally draining to provide freeze protection, it is
very important that you use a
non-positive seal valve or drill a hole (1/8"--1/4") in the
diverter of a positive seal valve to allow the collectors to drain.
Alternatively, the GL-
235 control can provide recirculate freeze protection. If enabled, when the GL-235
senses a freeze condition at the collector sensor, it will allow circulation of relatively
warm water from the pool to the collector panels.
The GL-235 will allow recirculation when the collector temperature falls below 40ºF and
will stop circulation when the collector temperature rises above 42ºF. While this type
of freeze protection has proven to be adequate in relatively mild climates, it is extremely
important that the sensors be properly placed and that the homeowner realize that the
system is unprotected in the event of a power failure. Recirculate freeze protection is
NOT recommended in climates where freezing temperatures are common or last for
extended periods.
Hayward strongly recommends the use of GC-3 freeze snap switches if freeze protection
is being utilized. Snap switches should be wired in series with the collector sensor.
Placement of the snap switches at the coldest point of the collector array and exposed
plumbing will help assure that freeze protection starts early enough to protect the
system.
The GL-235 is shipped from the factory with recirculate freeze protection disabled (the
jumper is present but installed on one pin only). To activate recirculate freeze
protection, install the jumper across both pins marked “RECIRC”, located near the top
right of the main circuit board.
If recirculate freeze protection is to be used on a GL-235, either:
• The filter pump must be set for continuous operation
or
• The GL235 High Voltage Output must be wired for Timer Override function.
Nocturnal Cooling
The GL-235 has nocturnal cooling logic, which can be enabled/disabled via a jumper
on the main circuit board. During nighttime hours, when enabled, the GL-235 will
circulate relatively warmer water from the pool to the collector panels, thus cooling the
pool over time. The GL-235 will circulate water when the collector temperature AND
the pool temperature is hotter than the high limit setting. Circulation will stop when the
collector temperature is 3ºF less than the pool temperature OR the pool temperature is
cooler than the high limit setting. The GL-235 is shipped from the factory with nocturnal
cooling disabled (the jumper is present but installed on one pin only). To activate
nocturnal cooling, install the jumper provided onto the two pins marked “COOLING”
located near the top right of the main circuit board.
If nocturnal cooling is to be used, either:
• The filter pump must be set for continuous operation
or
• The GL235 High Voltage Output must be wired for Timer Override function.
9
4
Measuring Voltage of Pool Sensor
(Use the same method to measure the Solar Sensor)
Figure 5
