JOHNSON CONTROLS
60
FORM 100.50-NOM12
ISSUE DATE: 04/02/2019
SECTION 5 – SEQUENCE OF OPERATION
• Series 100 units ordered as SZVAV do not have a
duct static pressure transducer installed.
•
SZVAV configured units do not have the ability to
control duct static pressure and have no high duct
static pressure protection.
FlexSys
™
• A FlexSys unit type is an HVAC system that utilizes
an underfloor plenum to provide conditioned air up
from the floor level instead of overhead like a tradi
-
tional VAV system. The underfloor plenum may or
may not have VAV boxes installed that control the
amount of air to the space.
• A FlexSys system has a supply fan controlled by a
VFD to maintain a constant duct static pressure.
• The VFD speed is controlled by a duct static pres-
sure transducer that also provides high duct static
pressure protection.
•
A FlexSys configured unit also has a return air by
-
pass duct installed that bypasses return air around
the direct expansion (DX) evaporator coil and re-
introduces this air at the supply fan inlet.
UNIT OVERALL STATUS
• The Series 100 UI displays an overall status at the
top of the STATUS menu.
• This overall status can be used to determine if the
status is Normal or if there is a problem.
• All three unit types use the same-overall status
messages.
•
lists the different overall status messages.
• Press the HISTORY key on the UI to determine the
active warnings or alarms.
Phase Monitor
• Series 100 units have a 3 phase power monitor
factory installed, except those units with dual
point power.
• The phase monitor is wired in series between
CTB1 terminal 4 and the unit control or rocker
switch.
•
It is factory set to the unit voltage, but slight field
adjustment may be necessary.
• The location of the phase monitor varies per unit
tonnage range.
TABLE 19 -
OVERALL STATUS MESSAGES
LOCAL-STOP
1
Unit control switch is turned OFF
No 24 VAC power to SD terminal on CTB1
Power phase monitor is in a fault condition
Building automation system (BAS) command to UNIT_STOP (AV93 or BV17)
RUN
The unit is ready to RUN
WARNING
The IPU board has recognized an Active Warning
UNIT LOCKOUT
The IPU board has recognized and Active Alarm that has caused the unit to shut down
UNSTABLE SYSTEM
This message displays when the IPU board sees a significant drop in supply fan VFD speed. This
is only applicable when the unit is twinned together with another unit
SMOKE PURGE 1
This message shows the unit is operating in a Smoke Purge sequence. This specialized sequence
is not normally used. Smoke Purge sequences are discussed later in this section
SMOKE PURGE 2
This message shows the unit is operating in a Smoke Purge sequence. This specialized sequence
is not normally used. Smoke Purge sequences are discussed later in this section
SMOKE PURGE 3
This message shows the unit is operating in a Smoke Purge sequence. This specialized sequence
is not normally used. Smoke Purge sequences are discussed later in this section
1. The control switch, SD terminal, and phase monitor are wired in series and provide 24 VAC to the I/O board. The SD terminal on CTB1 is
where a remote shutdown device can be connected. A jumper is installed between 24 VAC and SD terminal from the factory.
