JOHNSON CONTROLS
137
SECTION 5 – SEQUENCE OF OPERATION
FORM 145.05-NOM7
ISSUE DATE: 10/31/2019
5
The following limitations apply:
• If the “MORNING WARM UP OPT TIME” ex-
ceeds the “MORNING WARM UP MAX TIME,”
the “MORNING WARM UP OPT TIME” is
“MORNING WARM UP MAX TIME.”
• If the “MORNING WARM UP OPT TIME” is de-
termined to be less than 15 minutes, the “MORN-
ING WARM UP OPT TIME” is set to 15 minutes.
• The default values for “DAILY WARM UP TIME
DAY 1,”
“
DAILY WARM UP TIME DAY 2,”
and
“DAILY WARM UP TIME DAY 3 INCH is ini-
tially set at 60 minutes. These values can be re-
set to the default values by turning the “MORN
WARM UP” to USER DISABLED and back to
USER ENABLED.
Sequence of Operation
1. The supply fan starts.
2. After 5 minutes, the Unit Controller compares the
Return Air Temperature to the “RAT HEATING
SETPOINT.”
3. If the Return Air Temperature is not less than the
“RAT HEATING SETPOINT” minus 1.0°F, the
Unit Controller does not energize the heating se-
quence and it sets the daily warm up time to 5
minutes.
4. If the Return Air Temperature is greater than or
equal to the “RAT HEATING SETPOINT,” the
Unit Controller energizes the heating sequence
based on the “MORNING WARM UP OPT
TIME.”
5. The Unit Controller sets the “SUPPLY AIR TEMP
ACTIVE SP” as follows:
• VARIABLE AIR VOLUME and FLEXSYS
units – “HEATING SAT”
• CONSTANT VOLUME units – “2ND
STAGE HEATING SETPOINT”
6. The heat source remains energized until the Re-
turn Air Temperature is greater than or equal to
the “RAT HEATING SETPOINT” plus 0.5°F or
the unit goes into the OCCUPIED mode.
7. The Unit Controller records the time the heat
source is energized as described below:
a. If the heat source is terminated because
it is within 0.5°F of the “RAT HEATING
SETPOINT,” the Unit Controller replaces
the Day 3 time with the Day 2 time; the Day
2 times with the Day 1 time; and the Day 1
time with the current value. It averages the 3
values and adds 10 minutes, which becomes
the new “MORNING WARM UP OPT
TIME” for the next day.
b. If the heat source does not bring the RE-
TURN AIR TEMP up to the “RAT HEAT-
ING SETPOINT” before the Morning Warm
Up is stopped, the Unit Controller calculates
an approximate daily warm up time using
calculation built into the Unit Controller for
a new start time for heating operation.
If the time from when heat is started and
Morning Warm Up is stopped is less than 10
minutes, the Unit Controller uses the daily
warm up time for the previous day and does
not approximate a warm up time.
If the approximate daily warm up time ex-
ceeds the “MORNING WARM UP MAX
TIME,” the daily warm up time is set equal to
the “MORNING WARM UP MAX TIME.”
VENTILATION SYSTEM
Overview
The following can be used on units that have a recom-
mended Johnson Controls airside economizer installed.
The Unit Controller can be configured for several dif-
ferent damper and ventilation options. The damper op-
tions are:
• None
• 2-Position
• Standard
For the Ventilation System to be active, the following
must occur:
• The UNIT MODE must be OCCUPIED
• There must be a 24V output from the Unit Control-
ler to the Supply Fan control circuit. This output is
contained at connector J17.
• There must be a 24VAC input to the Unit Con-
troller from the supply fan air proving switch to
verify Supply Fan operation 120 seconds after the
Supply Fan circuit is energized. This input is con-
tained at connector J13 – terminal 2.