Hayward GL-235 Solar Pool Controller
Part Number: GL-235
Description
The GL-235 is a differential temperature controller designed for solar assisted pool and spa heating systems. It automates the diversion of water through solar panels or bypass circuits based on real-time collector and pool temperatures.
Compatibility & Fitment
- Works with 120 V or 240 V input power and supports 12 V or 24 V actuator output.
- Used in solar pool heating systems that integrate collector sensors and pool sensors for automatic control.
- Ideal when upgrading to automatic solar control or replacing an existing GL-235 or equivalent differential controller.
Features & Specifications
- Single-dial selection for desired pool/spa temperature (70 °F to 104 °F).
- Automatic functions include differential heating (on at ~4 °F difference, off at ~1.5 °F difference), optional nocturnal cooling, and selectable freeze-recirculation protection.
- LED indicators for power, heating mode, cooling mode and sensor fault.
- Low-voltage output for valve actuator; optional high-voltage output for control of a booster pump or filter pump in GL-235-HV variant.
- Enclosure rated for outdoor mounting with durable weather-protective design.
Installation Notes
Mount the controller vertically with knockouts facing downward, at least five feet horizontally from the pool edge. Connect input power (120/240 V), connect two collector and pool sensors, wire the actuator or pump as required, set the desired temperature dial, and test the system in AUTO mode. Confirm that the valve or pump activates when the collector temperature exceeds pool temperature by the set differential.
Maintenance Tip
Annually verify sensor accuracy, check operation of the valve or pump output, inspect the LED indicators and wiring connections, and ensure the enclosure remains sealed. Replace the controller if LED indicators show sensor faults or failing logic.
