King Electric SST 3 - Manual (Page 21)

Adjustable Electronic Thermostat TRACON
®
Model SST–3 (P/N 24492)
Instruction Manual
24494 Rev. - 04/12 (800) 234-4239 http: www.networketi.com Environmental Technology, Inc. 21 of 28
ERROR CODES
Four error codes or conditions can be indicated in the display window of the
SST–3. They are explained below.
LL
Low temperature limit error
This error code indicates that the temperature has been 4 degrees F (or 2
degrees C) below the set point for 30 seconds or longer. This error
condition will go away once the situation is addressed. The most likely
cause of this condition is that the heaters are broken or disconnected or,
possibly, not powerful enough if it is very cold outside. This error code
can also be indicated when the unit is first started up if the ambient
temperature is below the set point.
GFA
Ground Fault alarm error
This indicates a ground fault condition external to the SST–3 unit. In this
case, check the wiring and cables leading to and from the unit. After the
problem has been located and corrected, press the GFEP Test/Reset
button to see if the situation has been resolved.
GFC
Ground Fault Circuit error
This code indicates a failure of the ground fault circuitry internal to the
SST–3 unit. Press the GFEP Test/Reset button to try to clear the
situation. If pressing the GFEP Test/Reset button does not resolve the
situation, contact Environmental Technology Technical Support for
possible service options.
Prb
Temperature Probe error
This error code indicates that the temperature probe is either bad or not
properly connected. Remove power from the unit and make sure the
temperature probe is properly connected to the two leads on the right side
of the PC board as shown in Figure 3 on page 11. If the temperature
probe is properly connected, then either the probe or the unit might require
service. To troubleshoot this situation, using a digital voltmeter (DVM),
check the resistance of the probe when disconnected from the circuit. The
reading should be about 100K at room temperature. If the reading is very
low (3K or less) or very high (9M or higher), the temperature probe is bad.
If the probe is OK, try substituting a 20K to 200K resistor and if the alarm
persists, the problem is likely internal to the unit.