产品介绍

Back up systems automatically opens tunnel curtains or vent doors and starts up selected fans if ever a controller fails. Includes 6 relays total. 5 relays can be used to back up fans or heaters and 1 relay for override of curtains or vent doors. Requires the use of at least one mechanical thermostat (AC1251 or similar). Has inputs for up to 3 thermostats for high or low tempurature override.