WaterFurnace Envision Low Sill - Manual (Page 31)

31
ENVISION LOW SILL CONSOLE INSTALLATION MANUAL
consecutive faults occur in 60 minutes during a single
heating or cooling demand, the unit will go into lockout
mode, turning off the compressor, and enabling the alarm
output 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 and
will be field selectable for 15°F 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 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.
Controls cont.