133
JOHNSON CONTROLS
5276178-JIM-C-0118
5
FlexSys with Bypass Damper
The setpoint at which the compressors are controlled
to will be the
“EVAP LEAVING AIR TEMP HIGH”
set
point if either of the following is true:
•
The Return Air Humidity sensor is not reliable.
•
The Return Air Enthalpy is less than the “RESET
ENTHALPY SP”.
The setpoint at which the compressors are controlled
to will be the
“EVAP LEAVING AIR TEMP LOW”
set
point if either of the following is true:
•
The Return Air Enthalpy is equal to or greater
than the
“RESET ENTHALPY SP”.
•
The
“UNDERFLOOR SLAB DEWPOINT”
is
greater than or equal to the
“UNDERFLOOR
SLAB TEMP”
minus 2.0°F for 120 seconds.
The following parameters are programmed through the
User Interface:
•
“EVAP LEAVING AIR TEMP LOW”
-
SETPOINTS key / COOLING subsection.
•
“EVAP LEAVING AIR TEMP HIGH”
-
SETPOINTS key / COOLING subsection.
•
“RESET ENTHALPY SP”
- SETPOINTS key /
COOLING subsection.
•
The unit will control the supply air temperature
to the
"MX SUPPLY AIR TEMP".
FlexSys without Bypass Damper
The
SETPOINT AT WHICH THE COMPRESSORS ARE
CONTROLLED TO
is the
“MX SUPPLY AIR TEMP”.
THE “MX SUPPLY AIR TEMP”
is programmed through
the SETPOINTS key / COOLING subsection of the
User Interface.
•
The unit will control the supply air temperature
to the
"MX SUPPLY AIR TEMP".
COMPRESSOR CONTROL
Whenever a change in the unit cooling status is made,
compressor turned ON, compressor turned OFF, etc.,
a 3-1/2 minutes Interstage Delay Timing is initiated.
During the countdown of the timer no compressor can
be staged ON or OFF until the timer has timed down.
The only exception to this would be if the compressor
protection circuit experienced a fault.
On CONSTANT VOLUME and VARIABLE AIR
VOLUME, when the Unit Controller enters an
active cooling mode, the Unit Controller sets the
“
COOLING CONTROL OFFSET”
to 2.0°F. The Unit
Controller compares the current
“SUPPLY AIR TEMP
CURRENT”
to the
“SUPPLY AIR TEMP ACTIVE SP”
plus or minus the
“COOLING CONTROL OFFSET”.
If the
“SUPPLY AIR TEMP CURRENT”
is greater
than the
“SUPPLY AIR TEMP ACTIVE SP”
plus
the
“COOLING CONTROL OFFSET”
and all the
compressors are not ON the Unit Controller will
initiate a call for compressor or additional compressor
operation based on the
“NEXT STAGE TO ENABLE”
(see Table 62).
If the
“SUPPLY AIR TEMP CURRENT”
is less
than the
“SUPPLY AIR TEMP ACTIVE SP”
minus
the
“COOLING CONTROL OFFSET”
and all the
compressors are not OFF the Unit Controller will turn
a compressor OFF based on the
“NEXT STAGE TO
DISABLE”
(see Table 62).
On a FlexSys unit with the current operating mode
set to
“OCC COOLING W/O BYP”
, when the Unit
Controller enters an active cooling mode, the Unit
Controller sets the
“COOLING CONTROL OFFSET”
to 2.0°F. The Unit Controller compares the current
“MX SUPPLY AIR TEMP CURRENT”
to the
“MX
SUPPLY AIR TEMP SETPOINT”
plus or minus the
“COOLING CONTROL OFFSET”
. If the
“MX
SUPPLY AIR TEMP CURRENT”
temperature is
greater than the
“MX SUPPLY AIR TEMP SETPOINT”
plus the
“COOLING CONTROL OFFSET”
and all the
compressors are not ON the Unit Controller will initiate
a call for compressor or additional compressor operation
based on the
“NEXT STAGE TO ENABLE”
.
If the
“MX SUPPLY AIR TEMP CURRENT”
temperature is less than the
“MX SUPPLY AIR TEMP
SETPOINT”
minus the
“COOLING CONTROL
OFFSET”
and all the compressors are not OFF the
Unit Controller will turn a compressor OFF based on
the
“NEXT STAGE TO DISABLE”
.
On a FlexSys unit with the current operating mode
set to
“OCC COOLING W/BYP”
, when the Unit
Controller enters an active cooling mode, the Unit
Controller sets the
“COOLING CONTROL OFFSET”
to 2.0°F. The Unit Controller compares the current
Содержание 40 25 TON
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