146
JOHNSON CONTROLS
5276178-JIM-C-0118
Sequence of Operation
EVAPORATOR SUPERHEAT CALCULATION
This feature is not available on this product.
STAGED INPUT FAULT
This can only occur on Constant Volume units with the
CONTROL METHOD set to
“STAGED”
. If the Unit
Controller receives a digital input for either Y1 or Y2
and W1 or W2 at the same time the Unit Controller will
declare a STAGED INPUT FAULT. When a STAGED
INPUT FAULT is active the Unit Controller will lockout
all cooling and heating operation. If either the Y1, Y2
or the W1, W2 digital input is removed for 10 seconds
the STAGED INPUT FAULT will be removed.
While the STAGED INPUT FAULT is active the
SENSOR / MISC STATUS subsection under the
STATUS key will display
“SAFETY LOCKOUT”.
In
addition a
“STAGED INPUT FAULT”
will be recorded
and displayed under the HISTORY key.
SYSTEM STABILITY CHECK
This feature is not available on this product.
ELECTRIC HEAT
Programmed Data
The following parameters must be programmed into
the Unit Controller:
•
“HEATING SYSTEM”
must be set to USER EN-
ABLE through the PROGRAM key, HEATING
subsection of the User Interface.
•
“HEATING SYSTEM TYPE”
must be set to
ELECTRIC through the OPTIONS key, HEAT-
ING subsection of the User Interface.
•
“ELEC HEAT CAPACITY”
must be set to the
nameplate capacity through the OPTIONS key,
HEATING subsection of the User Interface.
If the unit rating plate shows a capacity of 40 or
80 KW, set this parameter to 40 KW. If the unit
rating plate shows the capacity as 108 KW, set
this parameter to 40 KW (200V).
•
“1ST STAGE HEATING SETPOINT”
must be
programmed for CONSTANT VOLUME units
through the SETPOINTS key, HEATING subsec-
tion of the User Interface.
•
“2ND STAGE HEATING SETPOINT”
must be
programmed for CONSTANT VOLUME units
through the SETPOINTS key, HEATING subsec-
tion of the User Interface.
•
“HEATING SAT”
must be programmed for Vari-
able Air Volume and FlexSys units through the
SETPOINTS key, HEATING subsection of the
User Interface.
Heating Control Offset
The Unit Control calculates a
“HEAT CONTROL
OFFSET” (HCO)
using the following formula:
HCO =
KW x 3414
2.16 x CFM x STAGES
Where:
•
HCO =
“HEATING CONTROL OFFSET”.
•
KW =
“ELEC HEAT CAPACITY”.
•
CFM =
(See Table 65).
•
STAGES = Derived value based on the
“ELEC
HEAT CAPACITY”.
See Table 66 for number of
stages.
The
“HEATING CONTROL OFFSET”
will be rounded
up to the nearest half degree. If the
“HEATING
CONTROL OFFSET”
is calculated to be less than 2°F,
it will be set at 2.0°F.
When the UNIT MODE is
“COMFORT VENT
HEATING”
or
“SUP AIR TEMPERING”
is active, the
“HEATING CONTROL OFFSET”
will be fixed at 5.0°F
and the heat will be staged up or down as required.
Active SP
See Tables 60 and 61
to determine what the
“SUPPLY
AIR TEMP ACTIVE SP”
value is for CONSTANT
VOLUME units.
On Variable Air Volume and FlexSys units, the
“SUPPLY
AIR TEMP ACTIVE SP”
is the
“HEATING SAT”.
Heating Control
The Unit Control uses the
“SUPPLY AIR TEMP”
as
described below, to determine when to cycle stages
ON and OFF:
•
If the
“SUPPLY AIR TEMP”
is less than the
“SUPPLY AIR TEMP ACTIVE SP”
minus the
“HEATING CONTROL OFFSET”
additional
stages will be brought ON after an Interstage
Delay timer has expired.
•
If the
“SUPPLY AIR TEMP”
is greater than
the
“SUPPLY AIR TEMP ACTIVE SP”
plus
the
HEATING CONTROL OFFSET”
additional
stages will be turned OFF after an Interstage
Delay timer has expired.
Summary of Contents for 40 25 TON
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