5322625-UIM-A-0417
18
Johnson Controls Unitary Products
The above pressure switch is specifically designed to operate with R-
410A systems. R-22 pressure switches must not be used as replace-
ments for the R-410A pressure switches.
Indoor Circulating Blower
When the thermostat calls for “FAN,” the thermostat terminal “G” is
energized signaling the indoor blower control board to operate the cir-
culating blower to run continuously. The circulating blower airflow is
approximately 63% of the “HIGH COOL” airflow selected on the indoor
blower control board.
If a call for “COOL” occurs on “Y1,” the indoor blower runs at the “LOW
COOL” speed based on the “COOL” jumper setting. If a call for cool is
present on “Y1”+”Y2,” the indoor blower runs at the “HIGH COOL”
speed based on the “COOL” jumper setting.
If a call for “HEAT” occurs “W1” or “W1”+“W2”, the circulating blower
runs at the heat speed based on the “HEAT” jumper setting.
When the thermostat ends the call for “FAN,” the thermostat terminal
“G” is de-energized, and the indoor blower control board stops the cir-
culating blower operation.
Refer to the Ignition Control Board Fault Codes (Table 18) for a com-
plete list.
Delay Profiles
The Delay Profiles for each Delay jumper setting are shown in Table 15.
The levels shown in the Pre-Run, Short-Run, and Run Periods are a
percentage of the fan speed corresponding to the thermostat call. The
Post-Run and Off Delay levels are derived from the level of the previous
state, not the fan speed corresponding to the thermostat call.
If in Delay Profile B and in the Short-Run Period (82% of capacity) and
the thermostat call is removed, this causes the control to enter the Post-
Run state. The Post-Run state level for Delay Profile B is 100% of the
previous level, so the level during the Post-Run state is 82%.
HEATING SEQUENCE OF OPERATIONS
This dual fuel package unit has two methods of heating. Primary heat-
ing is accomplished by the heat pump section. Secondary heating, sup-
plemental heating and back up heating is accomplished by the gas
heating section. The gas heating section is also used to temper the
indoor discharge air during heat pump defrost operation. The system is
NOT
designed to run heat pump heating and gas heating at the same
time. However, the unit functions this way if the incorrect indoor thermo-
stat is used or if the incorrect indoor thermostat settings are selected. If
the heat pump and gas heating sections are run at the same time, HI
LIMIT trips may occur. A “Y1” or a “Y1” + “Y2” call without an “O” call
from the indoor thermostat is primary (heat pump) heat. A “W1” or a
“W1” + “W2” call from the indoor thermostat is secondary or emergency
(gas) heat. The indoor thermostat MUST lock out the heat pump section
on a call for supplemental heat or emergency heat.
TABLE 14 : Delay Profile Descriptions
Delay
Profile
Period
Cooling
Heat Pump
Heating
Level%
Time in State
(Minutes)
Level%
Time in
State
(Minutes)
A
Pre-Run
Bypass
Bypass
Bypass
Bypass
Short-Run
Bypass
Bypass
Bypass
Bypass
Run
100
No Limit
100
No Limit
Post-Run*
100
1
100
.5
Off Delay*
Bypass
Bypass
Bypass
Bypass
B
Pre-Run
50
2
Bypass
Bypass
Short-Run
82
5
Bypass
Bypass
Run
100
No Limit
100
No Limit
Post-Run*
100
1
100
.5
Off Delay*
Bypass
Bypass
Bypass
Bypass
C
Pre-Run
Bypass
Bypass
Bypass
Bypass
Short-Run
Bypass
Bypass
Bypass
Bypass
Run
100
No Limit
100
No Limit
Post-Run*
100
1
100
.5
Off Delay*
50
1
Bypass
Bypass
D
Pre-Run
Bypass
Bypass
Bypass
Bypass
Short-Run
63
1.55
Bypass
Bypass
Run
100
No Limit
100
No Limit
Post-Run*
100
1
100
.5
Off Delay*
63
0.5
Bypass
Bypass
*The Post-Run and Off Delay levels are derived from the level of the previous
state, not the fan speed corresponding to the thermostat call.
