Lennox ELXA Series Unit Information page 30

T3EH ELECTRIC HEAT SEQUENCE OF OPERATION (refer to figure 11) – 2 STAGE HEAT (50kW – Y Volt)
First Stage Heat Call
Heat Pumps (ELXP) - W1 heat demand operates the heat pump in heating mode.
Air Conditioners (ELXC) - W1 heat demand energizes the K9 heat relay.
K9−1 closes energizing K15, K16 contactors.
K15−1 closes energizing heating elements HE1 and HE2 assuming primary limit S15 and secondary limit S20 are closed
K16-1 closes energizing heating elements HE3 and HE4 assuming primary limit S15 and secondary limit S20 are closed.
Second Stage Heat Call
Air Conditioner (ELXC) − W2 heat demand energizes K19 contactor.
K19−1 closes, energizing one side of contactor K17 which energizes one side of K32 relay.
K32−1 closes energizing K17 contactor.
K17−1 closes, energizing heating elements HE5 and HE6 assuming primary limit S15 and secondary limit S20 are
closed.
Heat Pumps (ELXP) – W2 heat demand energizes K9 and K19 relays.
K9−1 closes energizing K15, K16 contactors.
K15−1 closes energizing heating elements HE1 and HE2 assuming primary limit S15 and secondary limit S20 are closed.
K16-1 closes energizing heating elements HE3 and HE4 assuming primary limit S15 and secondary limit S20 are closed.
K19−1 closes, energizing one side of contactor K17 which energizes one side of K32 relay.
K32−1 closes energizing K17 contactor.
K17−1 closes, energizing heating elements HE5 and HE6 assuming primary limit S15 and secondary limit S20 are
closed.
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