I do not know what thermostat you have...but s1 and 2 are normally for remote sensor. Thermostat in one spot but the temperature controlled in another. Very popular in commercial settings where the thermostat is in a office and the sensor in the retail space.
this is in a residential setting. On a heat pump. The t'stat is programmable etc. The AHU does not this wiring on the board.
Ok, then that one is for outdoor sensor. If you wanted you could hook up an outdoor sensor and have a set point for heat pump changover if you had a gas back up furnace...
no gas back up. heat strips and the heat pump only has 5 wir connections. r/w/y/o/c
Great...then you will just disregard the unapplicable wire terminals.
did that and the ahu terminal board faults. The led indicator (DAYTON 1.5T AHU) tells me thatthere are to many open relays?
What is model number of air handler