5750156-UIM-B-0919
Johnson Controls Ducted Systems
17
3 Red Flashes:
Indicates the pressure switch contacts are open when
they should be closed. Check for the following:
• Faulty inducer
• Blocked vent
• Broken pressure switch hose
• Disconnected pressure switch or inducer wires
• Faulty pressure switch
4 Red Flashes:
Indicates the main limit or rollout switch has opened its
contacts, which are normally closed. The control turns on the supply air
blower and inducer. Check for the following:
• Dirty filter
• Improperly sized duct system
• Incorrect blower speed setting
• Incorrect firing rate
• Loose limit switch or rollout switch wiring
• Faulty blower motor
If the limit switch does not close within 5 minutes, the control operates
as if the blower is not functioning. The control starts a hard lockout and
flashes the 11 Red Flashes fault code. If the limit switch does not close
after 15 minutes, the control operates as if a manual-reset rollout switch
has opened, and flashes the 5 Red Flashes fault code. See the 5 Red
Flashes and 11 Red Flashes descriptions below. If the main limit switch
opens five times within a single call for heat, the control flashes the 4
Red Flashes fault code and enters a one-hour soft lockout.
5 Red Flashes:
Indicates the limit circuit has been open for more than
15 minutes, usually meaning that a manual-reset rollout switch has
opened. Check for proper combustion air, proper inducer operation, pri-
mary heat exchanger failure, or a burner problem. The control enters a
hard lockout. After the problem is corrected, you must turn the power off
and back on to reset the control.
6 Red Flashes:
Indicates that while the unit was operating, the pres-
sure switch opened four times during the call for heat. Check for a faulty
inducer, blocked vent, or faulty pressure switch. The furnace locks out
for 1 hour and then restarts.
7 Red Flashes:
Indicates the flame could not be established during
three attempts for ignition. Check that the gas valve switch is in the On
position. Check for the following:
• Low gas pressure or no gas pressure
• Faulty gas valve
• Dirty or faulty flame sensor
• Faulty hot surface ignitor
• Loose wires
• Burner problem
The furnace locks out for 1 hour and then restarts.
8 Red Flashes:
Indicates the flame has been lost five times (four recy-
cles) during the heating cycle. Check for low gas pressure, a dirty or
faulty flame sensor, or a faulty gas valve. The furnace locks out for 1
hour and then restarts.
9 Red Flashes:
Indicates reversed line voltage polarity, a grounding
problem, or reversed low voltage transformer wires. Check the polarity
at the furnace and branch. Check the furnace grounding. Check that the
flame probe is not shorted to chassis. The furnace does not start the
ignition sequence until this problem is corrected.
10 Red Flashes:
Indicates the gas valve is energized with no call for
heat. The main blower and inducer blower run and no ignition sequence
starts as long as this condition exists. Check the gas valve and gas
valve wiring.
11 Red Flashes:
Indicates the limit circuit has remained open for more
than 5 minutes and less than 15 minutes. This condition is usually
caused by a failed blower motor or blower wheel. The control enters a
hard lockout. After the problem is corrected, you must turn the power off
and back on to reset the control.
Soft Lockout:
The control includes a soft lockout that resets automati-
cally after 1 hour. This provides protection for an unoccupied structure if
a temporary condition causes a furnace malfunction, for example, if a
temporary interruption in gas supply prevents the furnace from lighting.
In this case, the control keeps trying to light each hour and resumes
normal operation if the gas supply is restored.
Hard Lockout:
Some fault conditions cause a hard lockout, and you
must turn the power to the control off and back on to reset the control.
The control does not automatically restart.
COOLING SEQUENCE OF OPERATIONS
When the thermostat calls for COOL, the thermostat terminals G and Y
are energized, which signals the compressor, outdoor fan and indoor
blower to run.
With a call for Y, the circulating fan is energized at cooling speed.
When the thermostat is satisfied, terminals G and Y are de-energized,
de-energizing the compressor and outdoor fan.
After a cool fan off delay timing of 30 seconds, the circulating fan is de-
energized.
Safety Controls
The control circuit includes the following safety control:
• High Pressure Switch (HPS) - This switch protects against exces-
sive discharge pressures due to a blocked outdoor coil or an out-
door motor failure (opens at 650 ± 25 psig and closes at 450 ± 25
psig).
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 R-410A pressure switches.
CIRCULATING FAN
When the thermostat calls for FAN, the thermostat terminal G is ener-
gized, signaling the circulating fan to run at the G-Speed airflow.
If a call for COOL occurs (Y), the circulating fan switches to run at the Y-
Speed airflow.
If a call for HEAT occurs (W), the circulating fan switches to W-Speed
after a 30-second delay.
When the thermostat ends the call for FAN, the thermostat terminal G is
de-energized, de-energizing the circulating fan.
WARNING
The ability to properly perform maintenance on this equipment
requires certain expertise, mechanical skills, tools and equipment. If
you do not possess these, do not attempt to perform any mainte-
nance other than those procedures recommended in this Installation
Manual. Failure to heed this warning could result in serious injury
and possible damage to this equipment.
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