Lennox CBX32MV Series Manual page 37

D−ECB29-12.5CB, -15CB − 208/230V SINGLE PHASE − SEQUENCE OF OPERATION
FIRST−STAGE HEAT
1. When there is a call for heat, W1 of the thermostat
energizes the electric heat relay K32 with 24VAC.
2. When K32-1 closes, the blower is energized on
heating speed and economizer heat relay (K20-2) is
energized (see unit schematic figure 26).
3. Assuming the N.C. primary (S15) and secondary (S20)
limit switches are closed, electric heat element HE1 is
energized.
1
5
SECOND−STAGE HEAT
(remove jumper between W2 and R)
4. When K32-2 closes, the unit is ready for a second stage
heat demand. W2 of the thermostat sends a second
stage heat demand, energizing the electric heat relay
K33 with 24VAC.
5. When K33-1 and K33-2 close, assuming the N.C.
primary (S15) and secondary (S20) limit switches
are closed, electric heat elements HE2 and HE3 are
energized.
Page 37
4
2
3