ECB40‐8 and ECB40-8CB - 208/230V Single-Phase Sequence of Operation
FIRST-STAGE HEAT
1. W1 of the thermostat provides a W1 demand to the AHC. The AHC outputs a 22VDC signal to the K32 relay. K32-1 closes.
2. Assuming the N.C. primary (S15) and secondary (S20) limit switches are closed, electric heat element HE1 is energized.
SECOND-STAGE HEAT (remove jumper between W2 and R)
3. When K32‐1 closes, the unit is ready for a second stage heat demand. W2 of the thermostat provides a W2 demand
to the AHC. The AHC outputs a 22VDC signal to the K33 relay.
4. When K33‐1 closes, assuming the N.C. primary (S15) and secondary (S20) limit switches are closed, electric heat
element HE2 is energized.
CBX40UHV
1
1
4
4
2
Page 55
3