Johnson Controls LSWU035 User Manual

JOHNSON CONTROLS
133
SECTION 5 – SEQUENCE OF OPERATION
FORM 145.05-NOM7
ISSUE DATE: 10/31/2019
5
Operation In Supply Air Tempering with
Electric Heat
To enable Supply Air Tempering, the following condi-
tions must be met:
Operating Conditions
• For CV and VAV units, the SUPPLY AIR TEMP
must be less than or equal to the “SUPPLY AIR
TEMP ACTIVE SP” minus 2.5°F for 5 minutes
• For FlexSys without Bypass, the MX AIR TEMP
must be less than or equal to the “MX SUPPLY
AIR TEMP SETPOINT” 2.5°F for 5 minutes
• For FlexSys with Bypass, the RETURN AIR BY-
PASS CURRENT must be greater than or equal to
the MAXIMUM BYPASS minus 5%
• Economizer Output must be less than or equal to
5%
• Compressor operation must have been OFF for 10
minutes
• The MIXED AIR TEMP must be less than or
equal to the “SUPPLY AIR TEMP ACTIVE SP”
minus 5.0°F for 5 minutes
The stage heat stages up and down based on the fol-
lowing criteria:
• The heat section stages up if the SUPPLY AIR
TEMP is less than or equal to the “SUPPLY AIR
TEMP ACTIVE SP” minus 5.0°F
• The heat section stages down if the SUPPLY
AIR TEMP is greater than or equal to the “SUP-
PLY AIR TEMP ACTIVE SP” plus two times the
“HEATING CONTROL OFFSET” minus 5.0°F
If two times the “HEATING CONTROL OFF-
SET” minus 5.0°F is less than 5.0°F, the value is
set to 5.0°F
The following criteria must be met to terminate the
Supply Air Tempering:
• The MIXED AIR TEMP must be greater than or
equal to the “SUPPLY AIR TEMP ACTIVE SP”
for 5 minutes
Comfort Ventilation
For this mode of operation to function, the following
parameters must be programmed into the Unit Control-
ler through the User Interface:
• OPTIONS key, UNIT DATA subsection: UNIT
TYPE must be set to CONSTANT VOLUME
• PROGRAM key, VENTILATION subsection:
“COMFORT VENTILATION” must be USER
ENABLED
• SETPOINTS key, COOLING subsection: “OCC
ZONE COOLING SETPOINT” must be set
• SETPOINTS key, HEATING subsection: “OCC
ZONE HEATING SETPOINT” must be set
When “COMFORT VENTILATION” is selected, the
Unit Controller monitors the SUPPLY AIR TEMP and
uses it to energize mechanical cooling or heating even
though the zone sensor satisfies the normal heating or
cooling demand. This prevents the space temperature
from getting out of bounds before mechanical heating
or cooling is energized. This is usually used when there
is a large demand for outdoor air for ventilation.
If the SUPPLY AIR TEMP is equal to or greater than
the “OCC ZONE COOLING SETPOINT” plus 5.0°F,
the Unit Controller enters the COMFORT VENT
COOLING mode and initiate compressor operation.
If the SUPPLY AIR TEMP is equal to or less than the
“OCC ZONE HEATING SETPOINT” minus 5.0°F,
the Unit Controller enters the COMFORT VENT
HEATING mode and initiate heating operation. The
Unit Controller terminates COMFORT VENT mode if:
• The SUPPLY AIR TEMP is less than the “OCC
ZONE COOLING SETPOINT” minus 5.0°F for
5 minutes
• The SUPPLY AIR TEMP is greater than the
“OCC ZONE HEATING SETPOINT” plus 5.0°F
for 5 minutes
• The unit switches into the OCCUPIED HEAT-
ING OR OCCUPIED COOLING mode as a result
of a space sensor demand for cooling or heating

Johnson Controls LSWU035 Specifications

General

Brand	Johnson Controls
Model	LSWU035
Category	Chiller
Language	English