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Sequence of operation
(CoNt’D)
multiple Demand time line
If multiple 24VAC thermostat demands are energized at the same time to
the Low Voltage SIGNAL (speed) tap selections on the motor, it is designed to
operate at the highest value tap selection and ignore the communication
voltage on the lower value tap(s). Value equals the Low Voltage SIGNAL
(speed) taps where high speed is the highest value and low speed is the lowest
value.
Examples:
Air Conditioning or Heat Pump call on Y and G
Two Stage System call on both stages
motor on Command
1. HVAC System demand energizes 24VAC from thermostat connections to
multiple Low Voltage SIGNAL (speed) taps. There is no motor operation at this
point unless Step 2 occurs at the same time according the HVAC Systems fan
control(s) sequence of operation. This allows the HVAC System to maintain
any built in fan on delays.
2. HVAC System fan control(s) energize 115VAC to the High Voltage SIGNAL
connection(s). Motor will ramp (15 second maximum ramp) up to the
highest value Low Voltage SIGNAL (speed) tap selection that is energized.
motor off Command
1. HVAC System demand de-energizes 24VAC from thermostat connections
to all of the Low Voltage SIGNAL (speed) taps.
2. The motor will ramp down to a fixed reduced speed setting. Minimum
ramp time 45 seconds. After 45 seconds the motor will continue to
operate at the fixed reduced speed setting until the High Voltage SIGNAL
connection(s) are de-energized. This allows the HVAC System to maintain
any built in fan off delays.
3. HVAC System fan control(s) de-energize 115VAC from the High Voltage
SIGNAL connection(s). Motor will ramp (15 second maximum ramp) to off.
If this voltage is de-energized at the same time as Step 1 or during the ramp
down specified in Step 2, the motor will begin its off ramp immediately.
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Evergreen IM manual 01-13.indd 26
2/13/13 11:12 AM
