Page 43
K-ECB29‐10, -15, -20 and -25CB - 460V THREE PHASE - SEQUENCE OF OPERATION
FIRST STAGE HEAT
1- When there is a call for heat, W1 of the thermostat
energizes the electric heat relays K32 and K34 with
24VAC.
2- When K32‐1 closes, the blower is energized on heat
ing speed.
3- When K32‐1 and K32‐2 closes, assuming the N.C.
primary (S15) and secondary (S20) limit switches
are closed, electric heat elements HE1 and HE2 are
energized.
4- When K34‐1 closes, assuming the N.C. primary (S15)
and secondary (S20) limit switches are closed, electric
heat element HE3 is energized.
SECOND STAGE HEAT
(remove jumper between W2 and R)
5- When K34‐2 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 relays
K33 and K35 with 24VAC.
6- When K33‐1 closes, the blower (if not energized) is
energized on heating speed and economizer heat
relay K43 is energized (see 208/230VAC CB sche
matic).
7- When K33‐1, K35‐1, and K35‐2 contacts close, assum
ing the N.C. primary (S15) and secondary (S20) limit
switches are closed, electric heat elements HE4, HE5,
and HE6 are energized.
To Next Page
Loading...
Need help?
General
