8
Watlow Series 935A User’s Manual
Respond to a simple error
Display
Probable Cause
Recommended Action
Reversed thermo-
Change the sensor
couple connection
leads on Terminals
+ to –.
1 and 2.
Sensor type
Go to
{`In}
prompt, check
mismatch
selection (see p. 20), or check
or open RTD.
RTD, replace as necessary.
Sensor type
Go to
{`In}
prompt,
mismatch.
check selection
(see p. 20).
Open Thermocouple,
Check the sensor,
bad connection, or
replace as
broken wire.
necessary.
Electrical noise.
Cycle power to system. See if error
clears. Check system for electrical
interference.
Control is inoperable.
Check for line voltage at
terminals 7 and 8.
RDY
2
1
SET
• Simply correct the cause.
• Errors are non-latching
and self-clearing.
• For advanced error and
troubleshooting
information, go to p. 37.
If You See An Error Code:
1. Be aware that most errors are input (sensor) related.
2. Read the table below and follow its recommendations.
Table 2 - Error messages and recommended action
[`Er1]
[`Er2]
[`Er3]
[`Er4]
[`Er5]
[````]
