Lennox LCH060H4E

Page 70
Sequence of Operation -E1EH 7.5, 15, 22.5, 30 - G, J, M Voltage
HEATING ELEMENTS:
1 - Terminal Strip TB2 is energized when the unit discon
nect closes. TB2 supplies line voltage to electric heat
elements HE1 and HE2. Elements are protected by
fuse F3.
FIRST STAGE HEAT:
2 - Heating demand initiates at W1 in thermostat.
3 - 24VAC is routed to the A55 Unit Controller. After A55
proves N.C. primary limit S15, the electric heat contac
tor K15 is energized. A55 energizes the blower and
economizer.
4 - 7.5kW, 15kW units - N.O. contacts K15-1 close ener
gizing HE1.
22.5kW, 30kW units - N.O. contacts K15-1 close ener
gizing HE4, HE1 and HE2.
END OF FIRST STAGE HEAT:
5 - Heating demand is satisfied. Terminal W1 in the ther
mostat is de-energized.
6 - Electric heat contactor K15 is de-energized.
7 - 7.5kW, 15kW units - N.O. contacts K15-1 open de-en
ergizing HE1.
22.5kW, 30kW units - N.O. contacts K15-1 open de-en
ergizing HE1 and HE2.
Sequence of Operation -E1EH 7.5, 15, 22.5, 30 - Y Voltage
HEATING ELEMENTS:
1 - Terminal Strip TB2 is energized when the unit discon
nect closes. TB2 supplies line voltage to electric heat
elements HE1 and TB3. TB3 supplies line voltage to
HE2 and HE3. Elements are protected by fuses F3 and
or F42.
FIRST STAGE HEAT:
2 - Heating demand initiates at W1 in thermostat.
3 - 24VAC is routed to the A55 Unit Controller. After A55
proves N.C. primary limit S15, the electric heat contac
tor K15 is energized. A55 energizes the blower and
economizer.
4 - 7.5kW and 15kW units - N.O. contacts K15-1 close en
ergizing HE1.
22.5kW and 30kW units - N.O. contacts K15-1 close
energizing HE2 and HE3.
END OF FIRST STAGE HEAT:
5 - Heating demand is satisfied. Terminal W1 in the ther
mostat is de-energized.
6 - Electric heat contactor K15 is de-energized.
7 - 7.5kW, 15kW units - N.O. contacts K15-1 open de-en
ergizing HE1.
22.5kW, 30kW units - N.O. contacts K15-1 open de-en
ergizing HE2 and HE3.
Sequence of Operation -E1EH 7.5, 15, 22.5, 30 - P Voltage
HEATING ELEMENTS:
1 - Terminal Strip TB2 is energized when the unit discon
nect closes. TB2 supplies line voltage to electric heat
elements HE1 and TB3. TB3 supplies line voltage to
HE2 through HE6. Elements are protected by fuses F3
and F42.
FIRST STAGE HEAT:
2 - Heating demand initiates at W1 in thermostat.
3 - 24VAC is routed through A55 Unit Controller. After A55
proves N.C. primary limit S15, the electric heat contac
tor K15 (and K16 for 22.5kW units) is energized. A55
energizes blower and economizer.
7 - 7.5kW units - N.O. contacts K15-1 close energizing
HE1.
15kW units - N.O. contacts K15-1 & 2 close energizing
HE2 and HE3.
22.5kW units - N.O. contacts K15-1, K16-1 and K16-2
close energizing HE4, HE5 and HE6.
END OF FIRST STAGE HEAT:
5 - Heating demand is satisfied. Terminal W1 in the ther
mostat is de-energized.
6 - Electric heat contactor K15 (and K16 on 22.5kW units)
is de-energized.
7 - 7.5kW units - N.O. contacts K15-1 open de-energizing
HE1.
15kW units - N.O. contacts K15-1 & 2 open de-energiz
ing HE2 and HE3.
22.5kW units - N.O. contacts K15-1, K16-1 and K16-2
open de-energizing HE4, HE5 and HE6.