FORM 100.50-NOM7 (808)
19
JOHNSON CONTROLS
3
CONSTANT VOLUME SEQUENCE OF OPERATION
Under Constant Volume (CV) operation, the unit will
be controlled from one of the following sources in order
of priority:
• 7-Wire Thermostat.
• Space Sensor.
The controller will monitor each source and self-con-
figure to the source available with the highest priority.
Thermostat Control In CV Operation
Under thermostat control, the unit will monitor the G,
Y1, Y2, W1, and W2 thermostat inputs and control the
unit accordingly. Cooling Operation with Y1 and Y2
thermostat inputs are as follows:
Compressor Staging - ON:
• Y1 Only – Cooling Stage 1 – All compressors on
System 1.
• Y1 and Y2 – Cooling Stage 2 – All of the installed
compressors on System 1 and System 2.
• If Y2 is present without Y1, first start Cooling Stage
1, then start Cooling Stage 2.
Compressor Staging – OFF:
• Y2 Off – Shut Cooling Stage 2 off - System 2 com
-
pressors shut down.
• Y1 Off – Shut Cooling Stage 1 off - All compressors
on System 1 shut down.
Heating Operation with W1 and W2 Inputs
The controller can be configured for two types of heat;
stepped heat
(Gas or Electric) and
hydronic heat
(Hot
Water or Steam). Both stepped heat and hydronic heat
will be controlled to a low and high setpoint as indicated
by Heating Stage 1 and Heating Stage 2, respectively.
The controller will determine Heating Stage based on
the W1 and W2 thermostat inputs as follows:
• W1 Active Only – Heating Stage 1.
• W1 and W2 Active – Heating Stage 2.
• W2 Active Only – Heating Stage 2.
TIMEOUTS AND DELAYS
Table 2 lists the timeouts and delays that are to apply in
all functions unless an exception for a specific function
is specified.
TABLE 2 – TIMEOUTS AND DELAYS
Number
Timeout or Delay
Description
1
ASCD for cooling
This “minimum OFF time” delay will not allow any compressor to turn on, un-
less it has been off for 5 minutes, except when ASCD override is ON.
2
ASCD for SAT trip (cooling)
This will not allow any compressor to turn ON after an excessive SAT trip
has occurred, until it has been off for 5 minutes.
3
ASCD for SAT trip (heating)
This will not allow any heat stage to turn ON after an excessive SAT trip has
occurred, until it has been off for 5 minutes.
4
ASCD for heating
This “minimum OFF time” delay will not allow any heating stage to turn on,
unless it has been off for 2 minutes.
Exception: Supply Air Tempering = 1
min.
5
Energy Saver Delay
This is a 1 minute minimum time between turning on
compressor stages or heating steps.
6
Minimum Run Time for Cooling
A minimum run time of 3 minutes will apply to all compressors.
7
Supply Fan ASCD
This will not allow the Supply Fan to turn ON unless it has been OFF for 30
seconds.
8
Exhaust Fan Minimum Run Time
The exhaust fan will have a minimum ON time of 10 seconds.
9
Exhaust Fan Minimum Off Time
The exhaust fan will have a minimum OFF time of 1 minute.
10
Delay to allow SAT to stabilize
A 5 minute delay will be used any time a compressor, or a heating stage is
turned ON, or OFF, before using the SAT reading for any control decisions.
Summary of Contents for J Series
Page 85: ...FORM 100 50 NOM7 808 85 JOHNSON CONTROLS 6 ELECTRICAL NOTES AND LEGEND LD13862 ...
Page 87: ...FORM 100 50 NOM7 808 87 JOHNSON CONTROLS 6 LD13864 ...
Page 88: ...JOHNSON CONTROLS 88 FORM 100 50 NOM7 808 Service OPTI CONVERSION TO 25 40 TON LD13854 ...
Page 89: ...FORM 100 50 NOM7 808 89 JOHNSON CONTROLS 6 LD13865 ELEMENTARY DIAGRAM ALL UNITS ...
Page 91: ...FORM 100 50 NOM7 808 91 JOHNSON CONTROLS 6 ELEMENTARY DIAGRAM GAS HEAT 25 40 TON 575V LD13861 ...
