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Page 65
ECH16-7/10/15/20/25kW G, J, M VOLTAGE
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ECH16-20 / 25kW G, J, M VOLTAGE SEQUENCE OF OPERATION
NOTE - Call for heat is first stage heat for CHA16 units and second stage heat for CHP16/20 units.
1- On a call for second stage heat, relay K43 is energized.
K43-1 and K43-2 contacts close immediately.
2- When K43-1 closes, heat relay K15 is energized.
K15-1 closes immediately.
3- When K43-2 closes nothing happens as indoor blower
is already energized from first stage heat call.
4- When K15-1 closes, 7/10/15kW: heating elements
HE1, HE2 and HE3 are energized. HE1, HE2 and HE3
are connected in a wye" configuration. 20/25kW: heatĆ
ing elements HE4, HE5 and HE6 are energized. HE4,
HE5 and HE6 are configured in a wye" configuration.
5- When heating demand is satisfied, K43 is de-enerĆ
gized followed by K15 and all heating elemnts.