1183875-YIM-A-1014
52
Johnson Controls Unitary Products
Operation
Cooling Sequence of Operation
This section assumes Free Cooling is not available.
a. Compressors are controlled by the Y1 through Y2
thermostat inputs. If the Lead/Lag function is turned OFF,
a Y1 input energizes the C1 output. Thermostat Input
into Y2 energize the C2 output respectively.
b. The FAN output for indoor fan operation energizes with
any cooling output after the Fan On Delay for Cool
expires.
c. CN-FAN output energizes when either C1 or C2 is
energized.
d. A 30 second interstage delay occurs when multiple
stages are requested. When the thermostat cooling
inputs are lost and the minimum runtime expires, the
compressor outputs stage off.
NOTE:
A Y2 input without a Y1 input energizes C1 first and
then C2 30 seconds later.
Continuous Blower
By setting the room thermostat fan switch to "ON," the supply
air blower will operate continuously.
Intermittent Blower
With the room thermostat fan switch set to "AUTO" and the
system switch set to either the "AUTO" or "HEAT" settings, the
blower is energized whenever a cooling or heating operation is
requested. The blower is energized after any specified delay
associated with the operation.
When energized, the indoor blower has a minimum run time of
30 seconds. Additionally, the indoor blower has a delay of 10
seconds between operations.
Optional VAV Start-up and Control
Once placed into the Occupied Mode, the speed of the indoor
blower motor is controlled by duct static pressure. The Duct
Static set point (default = 1.5") is the pressure that the VFD
drive will maintain when operating the unit in VAV mode. If the
Table 22: Additional Static Resistance
Size
(Tons)
Model
CFM
Cooling Only
1
1. Add these values to the available static resistance in the respective Blower Performance Tables.
Economizer
2
,
3
2. Deduct these values from the available external static pressure shown in the respective Blower Performance Tables.
3. The pressure drop through the economizer is greater for 100% outdoor air than for 100% return air. If the resistance of the return air duct is
less than 0.25 IWG, the unit will deliver less CFM during full economizer operation.
4” Filter
2
Electric Heat kW
9
18
24
36
54
078 (6.5)
090 (7.5)
102 (8.5)
120 (10)
150 (12.5)
ZJ
1900
0.06
0.02
0.12
0.05
0.06
0.07
0.08
0.10
2100
0.07
0.02
0.13
0.06
0.07
0.08
0.09
0.11
2300
0.08
0.04
0.14
0.07
0.08
0.09
0.10
0.13
2500
0.09
0.11
0.16
0.08
0.09
0.10
0.11
0.14
2700
0.11
0.18
0.17
0.09
0.10
0.12
0.13
0.16
2900
0.12
0.25
0.19
0.10
0.11
0.13
0.14
0.18
3100
0.14
0.31
0.20
0.12
0.13
0.15
0.16
0.20
3300
0.16
0.37
0.22
0.13
0.14
0.17
0.18
0.22
3500
0.18
0.43
0.26
0.15
0.16
0.19
0.20
0.24
3700
0.20
0.49
0.27
0.17
0.18
0.21
0.22
0.26
3900
0.23
0.54
0.29
0.19
0.20
0.23
0.24
0.28
4100
0.25
0.58
0.32
0.21
0.22
0.25
0.26
0.31
4300
0.28
0.65
0.35
0.23
0.24
0.28
0.29
0.34
4500
0.30
0.69
0.38
0.25
0.26
0.30
0.31
0.37
4700
0.33
0.74
0.41
0.28
0.29
0.33
0.34
0.40
4900
0.36
0.78
0.44
0.30
0.31
0.35
0.37
0.43
5100
0.39
0.82
0.47
0.33
0.34
0.38
0.40
0.46
5300
0.42
0.86
0.51
0.35
0.37
0.41
0.43
0.49
5500
0.45
0.89
0.55
0.38
0.40
0.44
0.46
0.53
5700
0.48
0.93
0.58
0.41
0.43
0.47
0.49
0.56
5900
0.52
0.96
0.62
0.44
0.46
0.50
0.53
0.59
6100
0.56
0.98
0.67
0.47
0.49
0.53
0.56
0.62
6300
0.60
1.01
0.71
0.50
0.53
0.56
0.59
0.65
If the unit is operated with the optional manual bypass
switch in the LINE (BYPASS) position and there are
VAV boxes present in the duct system, then boxes must
be driven to the full-open position using a customer-
supplied power source to prevent over-pressurizing and
possible damage to the ductwork.