Troubleshooting
!
WARNING: Risk of Electrical Shock.
Hazardous voltages may be present at electrical
terminals and other exposed internal metal surfaces.
Do not touch any metal parts within the control when
cover is removed. Any contact with metal parts,
including with metal or conductive tools, may result
in serious injury or death.
If the control system does not function properly, verify
that the control is wired, and set up properly. If the
problem persists, use the following procedures to
determine the cause of the problem:
IMPORTANT: Follow these troubleshooting
procedures in the order presented. Do not skip any
of the steps in the procedures.
1. Check for proper voltage to the A419 control.
a. Remove the cover by loosening the four
captive cover screws.
b. Use a reliable AC voltmeter to check the
voltage between the COM and 120V or 240V
terminals on-line voltage models and the two
24V terminals on low-voltage models. Refer to
Figure 3.
c. The voltage must be between 20 and 30 VAC
for 24 VAC applications, 102 and 132 VAC for
120 VAC applications, 177 and 264 VAC for
208/240 VAC applications.
d. If the voltage reading is not within the required
range, check the power source and input
power wires for problems.
2. Check for proper sensor operation.
a. Disconnect all power sources to control.
b. Using an accurate thermometer, take a
temperature reading at the sensor location,.
c. Disconnect the sensor from the control.
d. Using an ohmmeter, measure the resistance
across the two sensor leads while the sensor
is at the temperature taken in Step 2b.
e. Consult
Figure 7 to verify that the measured
temperature and resistance conform to
established temperature and resistance
values.
f. If the measured values conform to the values
in
Figure 7, proceed to Step 3.
g. If the sensor’s measured resistance value is
substantially different from the expected value
for that temperature, check the sensor wiring.
If sensor wiring is okay, replace the sensor.
-40
-20
0
20
40
60
80
100
120
140
160
180
200
220
240
260
500 700 900 1100 1300 1500 1700 1900 2100
Resistance in Ohms
Temperature (°F)
-40
-20
0
20
40
60
80
100
120
Temperature (°C)
Figure 7: Temperature vs. Sensor Resistance
3. Check the A419 for proper operation.
Note:
Note:
Perform Troubleshooting Steps 1 and 2 before
performing this step.
a. Disconnect the load from the output relay
terminals.
b. Ensure that the Touchpad Lock jumper is
installed, so that the touchpad is unlocked.
c. Reconnect the sensor leads and supply power
to the control.
d. Replace the cover.
e. Check the control settings for proper values.
f. Press and hold MENU until Setpoint appears
(This takes about 2 seconds).
g. Press the Up and Down (arrows) to change
the Setpoint temperature above and below the
sensor temperature until the relay energizes
and de-energizes as shown in
Table 5.
If the anti-short cycle delay has a set
delay-time value greater than 0 minutes when the
control is powered On, the relay does not energize
until the time delay has elapsed.
h. If the output relay does not perform as
indicated in
Table 5, replace the A419 control.
i. If proper operation of the A419 control is
verified, reconnect the load and consult the
equipment manufacturer’s instructions for
troubleshooting the controlled equipment.
6 A419 Electronic Temperature Control with NEMA 1 and NEMA 4X Watertight Enclosures Installation Instructions
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