WaterFurnace Envisio Series Console - Manual (Page 32)

32
ENVISION CONSOLE - 50 HZ INSTALLATION MANUAL
Lockout Mode
Lockout mode can be activated by any of the following fault
signals: refrigerant system high pressure, refrigerant system
low pressure, freeze detection, and condensate overflow.
When any valid fault signal remains continuously active for
the length of its recognition delay, the controller will go
into fault retry mode, which will turn off the compressor.
After the Compressor short cycle delay, the compressor
will attempt to operate once again. If three consecutive
faults occur in 60 minutes during a single heating or cooling
demand, the unit will go into lockout mode, turning off the
compressor, enabling the alarm output, and setting the
blower back to low speed operation until the controller
is reset. If the control faults due to the low pressure input
(BI-3) being open during the pre-compressor startup check,
the control will go into lockout mode immediately, disabling
the compressor from starting and enabling the alarm output
(BO-6). The lockout condition can be reset by powering
down the controller, by a command from the BAS, or by the
holding the ESC and Return keys on the MUI for 5 seconds.
Freeze Detection Limit (AI-5)
The freeze detection limit sensor will monitor the liquid
refrigerant temperature entering the water coil in the
heating mode. If the temperature drops below the freeze
detection limit trip point for the recognition delay period,
the condition will be recognized as a fault. The freeze
detection limit trip point will be factory set for 30°F (-1°C)
and will be field selectable for 15°F (-9°C) by removing
a jumper wire on BI-5. The freeze detection limit fault
condition will be bypassed 2 minutes at normal compressor
startup, to allow the refrigeration circuit to stabilize. If the
freeze detection limit sensor becomes unreliable at any time
compressor operation will immediately be suspended until
the problem is corrected. This should be displayed as an
alarm on the BAS and the MUI. This alarm will be reported a
“Water Low Temp Limit” fault.
High Pressure (BI-11)
The high-pressure switch shall be a normally closed (NC)
switch that monitors the systems refrigerant pressure. If the
input senses the high-pressure switch is open it must disable
the compressor output immediately and count the fault. The
compressor minimum on time does not apply if the high-
pressure switch opens. The compressor will not restart until
the compressor short cycle time delay has been satisfied.
Low Pressure (BI-3)
The low-pressure switch shall be a normally closed (NC)
switch that monitors the systems refrigerant pressure. The
input shall be checked 15 seconds before compressor start
up to be sure the pressure switch is closed and then ignored
for the first 2 minutes after the compressor output (BO-2) is
enabled. If the switch is open continuously for (30) seconds
during compressor operation the compressor output (BO-2)
will be disabled. The compressor will not restart until the
compressor short cycle time delay has been satisfied.
Condensate Overflow
The condensate overflow sensing circuit will monitor
the condensate level as a resistance input to AI-3. If the
condensate water level rises resulting in the input resistance
rising above the set point for the recognition delay period,
the condition will be recognized as a fault. The condensate
will be subjected to a (30) second lockout delay which
requires that the fault be sensed for a continuous (30)
seconds before suspending unit operation.
Alarm Output (BO-6)
The alarm output will be enabled when the control is in the
lockout mode and will be disabled when the lockout is reset.
Test Mode
Raising the zone temperature input (AI-1) reading to
180–220°F [82-104°C] or by holding the ESC and down
arrow keys on the MUI for 5 seconds will put the control
into test mode. In test mode the random start delay and
the compressor fixed on delay time will both be shortened
to 5 seconds and the reversing valve will be allowed to
cycle with out shutting down the compressor. If an MUI is
connected to the control LED 8 will flash and the words
“Test Mode Enabled” will be shown on the LCD display
when the control is in test mode. Test mode will be disabled
after a power cycle, 30 minute timeout, or by holding the
ESC and Up arrow keys on the MUI.
Sequence of Operation
Power Fail Restart
When the controller is first powered up, the outputs will be
disabled for a random start delay. The delay is provided
to prevent simultaneous starting of multiple heat pumps.
Once the timer expires, the controller will operate normally.
Random Start Delay
This delay will be used after every power failure, as well as
the first time the compressor is started after the control
exits the unoccupied mode or the emergency shutdown
mode. The delay should not be less than 1 second and not
longer than 120 seconds. If the control is in test mode the
random start delay will be shortened to 5 seconds.
Compressor Fixed On Delay Time
The Compressor Fixed On Delay Time will ensure that the
compressor output (B02) is not enabled for (90) seconds
after the control receives a call to start the compressor.
This delay is adjustable from 30 – 300 seconds over a BAS
or a MUI. If the control is in test mode the Compressor
Fixed On Delay Timer will be shortened to 5 seconds.
Envision Controls cont.