Carrier 33CS Installation, Service, And Troubleshooting Instructions Download

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If the lockouts prevent IAQ mode from operating, the

system will not enter IAQ mode. These lockouts are user-
configured and measure outdoor humidity (category 14,
option 4), and outdoor temperature (category 14, options 5
and 6).

To clear a system error, use the Unit Reset function. The

Unit Reset function is in category 7, option 11. The default is
OFF. Use the left set point buttons to set the option to ON. The
TEMP system thermostat will reset all errors.
HIGH/LOW TEMPERATURE LIMIT EXCEEDED (SE11)
Heating Mode — An alarm is issued when any supply air sen-
sor in the system is above the first or second stage heating tem-
perature limits (depending on what stages are active).
Cooling Mode — An alarm is issued when any supply air sen-
sor in the system is above the first or second stage cooling tem-
perature limits (depending on what stages are active).

Refer to the High/Low Temperature Limit Time Guard sec-

tion on page 17 for more information.

Heat/Cool Mode Alarms are cleared from the system in

2 ways:
• Cycle power to the thermostat OFF, then ON.
• Reset the unit thermostat. Initiate a reset by switching the

Unit Reset to the ON configuration (Category 7, Option 11).

CANNOT DETECT INDOOR FAN OFF (SE12) — The
TEMP system thermostat will declare an SE12 if the FAN
relay is deenergized, but the fan status switch is sending an ON
status.

To clear a system error, use the Unit Reset function. The

Unit Reset function is in category 7, option 11. The default is
OFF. Use the left set point buttons to set the option to ON The
TEMP system thermostat will reset all errors.

To troubleshoot the error, check the operation and wiring of

the system fan.
STUCK GAS VALVE (SE13) — The Stuck Gas Valve
sequence is used to allow the system to properly react to a fail-
ure mode of the HVAC unit when the gas valve becomes stuck
in the open position. When this condition exists, the unit is
unable to shut off the heat. To minimize this problem, the inter-
nal limit switch trips causing the indoor fan to turn on and
remain on until the gas is manually shut off and the heat
exchanger cools to normal temperatures.

Without this feature, a VVT

system operating normally

would close each of its zone dampers as space conditions

warmed to set point. This causes the heated air to be recirculat-
ed back through the unit, further aggravating the overheating
problem. This allows space temperatures in the building to rise
to higher than normal temperature levels. However, this se-
quence reduces the temperature build-up in the unit and keeps
the heat exchanger operating within temperatures to prevent
failure.
During No System Mode — If the duct temperature rises to
greater than 175 F, the indoor fan is started. The fan will remain
on if that temperature does not drop below 150 F after 3 min-
utes. The bypass damper will be closed, and all zone dampers
will open to their maximum position. A Stuck Gas Valve alarm
(SE13) will be initiated.
During a Cooling Mode — If the duct temperature does not
drop below 100 F within 10 minutes, the cooling mode will be
dropped for 10 minutes. The ‘‘No System Mode’’ logic will
test for this condition.
During a Heating Mode — No action is required in this mode.

The alarm can be cleared or erased from the system in 2

ways:
• Cycle power to the thermostat off, then on.
• Initiate a reset by switching the Unit Reset option to the ON

configuration (category 7, option 11).

Storage Failure (SF) Errors —

A Storage Failure er-

ror is an error that corresponds to invalid information.

When an SF Error occurs, the TEMP system thermostat re-

places the invalid data in memory with factory selected default
values and the invalid information is not used to determine sys-
tem mode.

To clear an SF Error, enter the correct data at the TEMP sys-

tem thermostat by reconfiguring the associated options. See Ta-
ble 4 for a description of Storage Failure Errors.
EXAMPLE OF CLEARING AN SF ERROR — The TEMP
system thermostat displays a SF39 error. Look up SF39 in
Table 4. The affected configuration is Temperature Lockouts.
The default value is OFF. The desired setting is ON.

To clear the SF39 error manually, reconfigure the Tempera-

ture Lockouts option. The SF39 error should be cleared.
NOTE: If the SF error cannot be cleared, replace the TEMP
system thermostat and configure the new thermostat to match
desired settings.

Table 4 — Storage Failure (SF) Errors

LEGEND

NOTE: Table 4 continues on page 22.

ERROR

INFORMATION AFFECTED

DEFAULT VALUE(S)

SF01

Occupied Cooling Set Point

SF02

Occupied Heating Set Point

SF03

Cooling Set Point Low Limit