150
JOHNSON CONTROLS
5276178-JIM-C-0118
Sequence of Operation
than the
“SUPPLY AIR TEMP ACTIVE SP”
minus
the
“HEATING CONTROL OFFSET”
, the Unit
Control will close a binary contact to switch the
furnace section to high fire operation. However,
since the heat sections in this unit are single stage,
no change in firing rate will occur.
14. If the
“SUPPLY AIR TEMP”
continues to be less
than the
“SUPPLY AIR TEMP ACTIVE SP”
minus
the
“HEATING CONTROL OFFSET”
additional
gas heat sections, if available, are energized. The
sequence of operation for the additional heat sec-
tions is the same as discussed above.
MODULATING GAS HEAT
This feature is not available on this product.
HOT WATER/STEAM HEAT
Programmed Data
The following parameters 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 HOT
WATER HEAT / STEAM through the OPTION
key, HEATING subsection of the User Inter-
face.
•
“HW VALVE ACTION”
must be set to
“DI-
RECT” OR REVERSE”
through the PROGRAM
key, HEATING subsection of the User Inter-
face.
•
“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
“VARIABLE AIR VOLUM”
and
“FLEXSYS”
units through the SETPOINTS key, HEATING
subsection of the User Interface.
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 VOLUM”
and
“FLEXSYS”
units the
“SUPPLY AIR TEMP ACTIVE SP”
is the
“HEATING SAT”.
The STEAM or HOT WATER heat becomes active
as soon as the unit transitions into an OCCUPIED
HEATING or UNOCCUPIED HEATING mode.
Sequence of Operation
The Unit Control uses the
“SUPPLY AIR TEMP”
as
described below, to determine when to increase or
decrease the heating capacity:
•
If the
“SUPPLY AIR TEMP”
is less than the
Summary of Contents for 40 25 TON
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