Lennox LCH120H - Sequence of Operation (Electric Heat G, J, M, Y); Sequence of Operation (G, J, M Voltage); First Stage Heat Sequence (G, J, M Voltage); Second Stage Heat Sequence (G, J, M Voltage)

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SEQUENCE OF OPERATION EHA7.5, 15, 22.5, 30, 45, 60 kW - G, J, M and Y
G, J and M Voltage
1 Terminal strip TB3 is energized when the unit discon
nect closes. TB3 supplies line voltage to electric heat
elements HE1, HE2, HE3 and HE4. HE1 and HE2 ele
ments are protected by F3 and HE3 and HE4 elements
are protected by fuse F42.
First Stage Heat:
2 Heating demand initiates at W1 in the thermostat.
3 24VAC is routed through A55 Unit Controller. After
A55 proves N.C. primary limit S15, contactor K15 is
energized.
4- N.O. K15-1 contacts close energizing HE1 and HE2.
Second Stage Heat:
5 With first stage heat operating, an additional heating
demand initiates W2 in the thermostat.
6 A second stage heating demand is received by A55
control module.
7 A55 energizes contactor K16.
8 N.O. K16-1 contacts close energizing HE3 and HE4.
Y Voltage
1 Terminal strip TB3 is energized when the unit discon
nect closes. TB3 supplies line voltage to electric heat
elements HE1, HE2, HE3, HE4, HE5 and HE6.
First Stage Heat:
2 7.5 - 45 KW - Heating demand initiates at W1 in the
thermostat.
3 24VAC is routed through A55 Unit Controller. After
A55 proves N.C. primary limit S15 and S157, contac
tor K15 is energized.
4- N.O. K15 contacts close energizing HE1.
2 60KW - Heating demand initiates at W1 in the thermo
stat.
3 24VAC is routed through A55 Unit Controller. After
A55 proves N.C. primary limit S157, contactor K242 is
energized.
4- N.O. K242 contacts close energizing HE3 and HE4.
Second Stage Heat:
5 22.5 - 45 KW - With first stage heat operating, an addi
tional heating demand initiates W2 in the thermostat.
6 A second stage heating demand is received by A55
control module. After A55 proves N.C. primary limit
S58 and S159, contactor K16 is energized.
7 N.O. K16 contacts close energizing HE2 (22.5 and
30KW units only) and HE5 and HE6 (45 KW units only).
5 60KW - With first stage heat operating, an additional
heating demand initiates W2 in the thermostat.
6 A second stage heating demand is received by A55
control module. After A55 proves N.C. primary limit
S160 and S161, contactor K16 is energized.
7 N.O. K16 contacts close energizing HE5 and HE6.