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The aurora advanced vs control system cont, Operation description – WaterFurnace 7 Series User Manual

Page 27

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7 SERIES 50Hz 700A11 INSTALLATION MANUAL

Lockout – when locked out, the blower will operate

continuously in “G” blower speed setting. The Alarm output

(ALM) and Lockout output (L) will be turned on. The fault

type identification display LED1 (Red) shall flash the fault

code. To reset lockout conditions with SW2-8 On, the demand

call must be removed for at least 30 seconds. To reset lockout

conditions with SW2-8 Off, the demand call must be removed

for at least 30 seconds. Lockout may also be reset by

turning power off for at least 30 seconds or by enabling the

emergency shutdown input for at least 30 seconds.

Lockout With Emergency Heat - if the control is locked

out in the heating mode, and a call for emergency heat

is received, the control will operate in the emergency

heat mode while the compressor is locked out. The first

emergency heat output will be energized 10 seconds after

the W input is received, and the blower will shift to high

speed. If the control remains locked out, and the W input

is present, additional stage of emergency heat will stage

on after 2 minutes. When the W input is removed, all of

the emergency heat outputs will turn off, and the variable

speed ECM blower will shift to low speed.

High Pressure – fault is recognized when the Normally

Closed High Pressure Switch, P4-9/10 opens, no matter how

momentarily. The High Pressure Switch is electrically in series

with the Compressor Contactor and serves as a hardwired

limit switch if an overpressure condition should occur.

Low Pressure - fault is recognized when the Normally

Closed Low Pressure Switch, P4-7/8 is continuously open

for 30 seconds. Closure of the LPS any time during the 30

second recognition time restarts the 30 second continuous

open requirement. A continuously open LPS shall not be

recognized during the 2 minute startup bypass time.

Loss of Charge – fault is recognized when the Normally

Closed Low Pressure Switch, P4-7/8 is open prior to the

compressor starting.

Condensate Overflow - fault is recognized when the

impedance between this line and 24 VAC common or chassis

ground drops below 100K ohms for 30 seconds continuously.

Freeze Detection-Coax - set points shall be either -1.1°C

or -9.4°C. When the thermistor temperature drops below

the selected set point, the control shall begin counting

down the 30 seconds delay. If the thermistor value rises

above the selected set point, then the count should reset.

The resistance value must remain below the selected set

point for the entire length of the appropriate delay to be

recognized as a fault. This fault will be ignored for the initial

2 minutes of the compressor run time.

Freeze Detection-Air Coil - Air Coil Freeze Detection will

use the FP2 input to protect against ice formation on the

air coil. The FP2 input will operate exactly like FP1 except

that the set point is 30 degrees and is not field adjustable.

Over/Under Voltage Shutdown - An over/under voltage

condition exists when the control voltage is outside the

range of 18 VAC to 30 VAC. If the over/under voltage

shutdown lasts for 15 minutes, the lockout and alarm relay

will be energized. Over/under voltage shutdown is self-

resetting in that if the voltage comes back within range

of 18 VAC to 30 VAC for at least 0.5 seconds, then normal

operation is restored.

Other Lockouts and Alarms

Several other lockouts and alarms are shown in the Status

LED1 (LED1, Red) table with the associated codes visible on

the thermostat, ABC Fault LED, and in text in the AID Tool.

Operation Description

Power Up - The unit will not operate until all the inputs and

safety controls are checked for normal conditions. The unit

has a 5 to 80 second random start delay at power up. Then

the compressor has a 4 minute anti-short cycle delay after

the random start delay.

Standby - In standby mode the compressor, pump, and

blower motor are not active. The RV may be active. The

blower and compressor will be off.

Heating Operation - The unit will operate based upon demand

as calculated by the room setpoint algorithm. The resulting

compressor speed (1-12) will also select an appropriate blower

speed for the selected compressor speed. Aux Heat will not be

available (on IntelliZone2 Aux Heat is available on compressor

speeds 10-12) until after the 12th compressor speed has been

operational and still is not satisfying the thermostat, then

auxiliary electric heat will be activated.

Emergency Heat (W) - The blower will be started on G

speed, 10 seconds later the first stage of electric heat will

be turned on. 5 seconds after the first stage of electric

heat is energized the blower will shift to Aux speed. If the

emergency heat demand is not satisfied after 2 minutes the

second electric heat stage will be energized.

Cooling Operation - The unit will operate based upon

demand as calculated by the room setpoint algorithm.

The resulting compressor speed, speeds 1-9, (speeds 10-12

are reserved for SuperBoost mode only) will also select

an appropriate blower speed. The blower mode will also

CAUTION: Frequent cycling of power to the drive

can damage the drive! Wait at least 5 minutes

between cycles (connecting and disconnecting

power to the drive).

The Aurora Advanced VS Control System cont.