(1.) The thermostat closes R to G-and-Y circuits. The R-Y circuit starts outdoor unit, and R to G-and-Y circuits start furnace blower motor BLWM on high- cool speed.
(2.) The EAC terminals EAC-1 and EAC-2 are energized with 115v when blower motor BLWM is operating.
(3.) When thermostat is satisfied, R to G-and-Y circuits are opened. The outdoor unit stops, and furnace blower motor BLWM continues operating on high- cool speed for an additional 90 sec.
b.Two-Speed Cooling Outdoor Unit
(See Fig. 16 for thermostat connections.)
(1.) The thermostat closes R to G-and-Y1 circuits for low cooling or closes R to G-and-Y1-and-Y/Y2 circuits for high cooling. The R-Y1 circuits start outdoor unit on low-cooling speed, and R-G circuit starts furnace blower motor BLWM on low-cooling speed (same speed as for low-gas heat). The R to Y1-and-Y2 circuits start outdoor unit on high-cooling speed, and R to G-and-Y2 circuits start furnace blower motor BLWM on high-cooling speed.
NOTE: Y1 is not located on furnace control, but is found in outdoor unit. The furnace control CPU controls blower motor BLWM speed by sensing only G for low-cooling speed and Y/Y2 for high-cooling speed.
(2.) The EAC terminals EAC-1 and EAC-2 are energized with 115v when blower motor BLWM is operating on either cooling speed.
(3.) When thermostat is satisfied, R to G-and-Y1 or
Rto G-and-Y1-and-Y/Y2 circuits open. The outdoor unit stops, and furnace blower continues operating on cooling speed for an additional 90 sec.
4.Continuous Blower Mode
a.When R to G circuit is closed by thermostat, blower motor BLWM operates on low-gas-heat speed (identical to low- cool speed). Terminals EAC-1 and EAC-2 are energized with 115v as long as blower motor BLWM is energized.
b.During "call for heat," blower motor BLWM stops during ignitor warm-up (17 sec), ignition (7 sec), and blower on delay (45 sec), allowing furnace heat exchangers to heat up quickly.
(1.) The blower motor BLWM reverts to continuous blower speed after heating cycle is completed. In high-gas-heat, furnace control CPU holds blower mo- tor BLWM at high-gas-heat speed during selected blower off delay period before reverting to continuous blower speed.
(2.) When thermostat "calls for low cooling," blower motor BLWM continues to operate on low-cool speed. When thermostat is satisfied, blower motor BLWM continues on continuous blower speed.
(3.) When thermostat "calls for high cooling," blower motor BLWM operates on high-cool speed. When thermostat is satisfied, blower motor BLWM operates an additional 2 sec on high-cool speed before reverting back to continuous blower speed.
(4.) When R to G circuit is opened, blower motor BLWM continues operating for an additional 90 sec if no other function requires blower motor BLWM operation.
5.Heat Pump
NOTE: An accessory interface kit is required with single-speed heat pumps. See interface kit Installation Instructions for single- speed heat pump thermostat and interface connections. No inter- face kit is needed for 2-speed heat pumps. See 2-speed heat pump Installation Instructions for thermostat connections.
a.Single-Speed Heat Pump Cooling
(1.) The thermostat and interface kit close R to G-and- Y/Y2 circuit to start furnace blower motor BLWM on high-cooling speed. (Y/Y2 input to furnace control is necessary to provide adequate cooling airflow.)
(2.) The EAC terminals EAC-1 and EAC-2 are energized with 115v when blower motor BLWM is operating.
(3.) When thermostat is satisfied, furnace blower motor BLWM continues operating on high-cooling speed for an additional 90 sec.
b.Two-Speed Heat Pump Cooling
(1.) The thermostat R to G circuits start furnace blower motor BLWM on low-cooling speed. Thermostat R to G-and-Y/Y2 circuits start furnace blower motor BLWM on high-cool speed.
NOTE: The furnace control CPU controls blower motor BLWM speed by sensing only G (for low-cooling speed) and Y2 (for high-cooling speed).
(2.) The EAC terminals EAC-1 and EAC-2 are energized with 115v when blower motor BLWM is operating on either cooling speed.
(3.) When thermostat is satisfied, furnace blower motor BLWM continues operating on cooling speed for an additional 90 sec.
c.Single-Speed Heat Pump Heating
(1.) The thermostat and accessory interface kit R to G- and-Y/Y2 circuits start furnace blower motor BLWM on heat pump high-heat speed (identical to high-cool speed).
(2.) The EAC terminals EAC-1 and EAC-2 are energized with 115v when blower motor BLWM is operating.
(3.) When thermostat is satisfied, furnace blower motor BLWM continues operating on heat pump high-heat speed for an additional 90 sec.
d.Two-Speed Heat Pump Heating
(1.) The thermostat closes R to G circuit for low heat and starts furnace blower motor BLWM on heat pump low-heat speed (identical to low-cooling speed). Clos- ing R-Y/Y2 circuit to furnace provides blower motor BLWM heat pump high-heat speed.
NOTE: The furnace control CPU controls blower motor BLWM speed by sensing only G (for heat pump low-heat speed) and Y2 (for heat pump high-heat speed).
(2.) The EAC terminals EAC-1 and EAC-2 are energized with 115v when blower motor BLWM is operating on either heating speed.
(3.) When thermostat is satisfied, R to G or R to G-and- Y2 circuits are opened. After opening R to G-and-Y2 circuit, the furnace blower motor BLWM continues operating on heating speed for an additional 90 sec.
(4.) Opening R-Y2 circuit reduces blower motor BLWM speed to heat pump low-heat speed.
6.Defrost
a.When furnace control R to W/W1-and-Y/Y2 circuits are closed, furnace control CPU continues blower motor
