HPAL Dual Relay Extension Unit

• Provides an additional two relay outputs.
• This unit can only be used with some thermostats.

See also:

• HP22 Two Level Thermostat.
• HP26 Two Zone Floating Proportional Controller.
• HP47 Thermal Chamber Control.
• HP54 Four Stage Step Control.
• HD38 Six Step Ventilation Controller.
• HD40 Greenhouse Controller.