When a demand for heat is satisfied, the system:
Opens TT (or Heat 1) to remove the boiler's call for heat.
Continues to operate the fan for 45 seconds; also operates the pump contacts for 30 seconds.
3.6.2 Cooling Mode
Upon a call for cooling from the thermostat:
R to Y1 or Y2 is energized
The fan is energized and:
Operates at Y1 or Y2 speed.
Energizes the O/B terminal if there is a heat pump.
When cooling demand is satisfied, the air handling unit:
Opens the compressor S1 and /or S2 contacts, and de-energizes O/B if there is a heat pump.
The fan continues to operate for 45 seconds.
3.6.3 Heat Pump Mode
Upon a call for heat from a heat pump:
R to Y1 or Y2 is energized.
R to O/B remains de-energized.
The fan is energized and:
Operates at Y1 or Y2 speed.
Operates a low speed for 60 seconds.
When heating demand is satisfied:
The air handling unit opens the compressor S1 and /or S2 contacts.
The fan continues to operate for 45 seconds.
3.6.4 Humidification Mode
Upon a call for humidification from the thermostat:
G to W is energized.
The humidifier's contacts (24V output) will close.