Hayward GL-235 AquaSolar dual differential solar controlHayward AquaSolar Control, GL-235 In stock$39699
Hayward GL-235 AquaSolar dual differential solar control
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Hayward AquaSolar Control, GL-235

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$39699
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Quick overview

  • Dual differential control Compares water temperature against panel temperature and runs solar only when the panels are actually gaining heat.
  • Selectable high limit Set the ceiling and the control stops adding solar heat once the water is where you want it.
  • Programmable freeze protection Runs the system on a freeze condition rather than leaving standing water in the panels.
  • Automatic nocturnal cooling Circulates at night to shed heat, which is the answer for pools that overheat in hot climates.
  • Pools, spas and hot tubs The same control covers all three applications.
  • Genuine Hayward AquaSolar control, part number GL-235.
Full description and specifications ↓

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Product details

The Hayward GL-235 AquaSolar is a dual differential control for solar heating of pools, spas and hot tubs. It decides when the solar panels are worth using and manages the system from there.

How differential control works

A solar panel is only useful while it is hotter than the water. The control reads both temperatures and calls for solar when the difference is in your favor, then stops when it is not. Without that logic a solar loop happily pumps water through cold panels at dusk and cools the pool it was meant to heat.

The rest of the feature set

A selectable high limit caps how warm the water gets, so the system stops adding heat at your chosen temperature instead of running all afternoon. Freeze protection is programmable, which matters anywhere a night can drop below freezing with water sitting in the panels. Automatic nocturnal cooling runs the loop after dark to dump heat, which is the fix for pools that overheat in hot climates.

Where it fits

The same control is used on pools, spas and hot tubs, so a single unit handles most residential solar installations.

Specifications
Brand Hayward
Manufacturer part number GL-235
UPC 761418003907
Type Dual differential solar control
Application Solar heating of pools, spas and hot tubs
Functions Differential temperature control, selectable high limit, programmable freeze protection, automatic nocturnal cooling
Shipping weight 3.15 lb
Ships Parcel

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Questions and answers

What people ask about this product, answered by our pool techs.

What does a differential control actually do?
It compares the pool water temperature with the solar panel temperature and only diverts flow to the panels when the panels are warmer, so you never pump heat out of the pool.
What is nocturnal cooling for?
Pools in hot climates can run too warm. The control can circulate water through the panels at night to shed that heat automatically.
Does it protect against freezing?
Yes. Freeze protection is programmable, so the system responds to a freeze condition rather than sitting with water trapped in the panels.
Can I set a maximum pool temperature?
Yes. The high limit is selectable, and once the water reaches it the control stops calling for solar heat.
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