AERCO Electronic Control Valve User Manual
Page 22
VA-115 INSTRUCTIONS – ELECTRONIC CONTROL VALVE, CXT-E
7-2
TABLE 7-1. TROUBLESHOOTING – CONTROL VALVE CXT-E
NO.
FAULT INDICATION
PROBABLE CAUSE
CORRECTIVE ACTION
T1
System not operating.
Control Valve is closed
and outlet water temp. is
far below setpoint.
1. No power supplied to
Control Valve
2. Control signal not
being supplied from
Temp. Controller.
1. Disconnect Valve Actuator plug and
verify that 24 VDC power is present at
pin 2 of Actuator cable. Restore power
if necessary. If System includes an
over-temp limiting device, ensure that it
has not tripped.
2. Verify presence of 4 - 20 mA control
signal at pin 3 of Actuator cable. If
control signal is not present,
troubleshoot Temp. Controller.
T2
System over-heats by
more than 10°F above the
desired setpoint.
Outlet temp is below Over-
Temp limit setting
CAUTION
Over-tightening the Pack-
ing Nut may trap the Valve
Stem and slow or stop
Valve motion.
1. Control Valve not fully
closed.
2. Temp. Controller not
set properly or
defective.
3. Valve Actuator not
properly secured to
Linkage Assembly.
4. Foreign matter in
Valve Seat.
1. Check the 4 – 20 mA control signal
being supplied to Actuator. If signal is
greater than 4 mA when heater outlet
temperature is 10°F (or more) above
the desired setpoint, proceed to next
item in list.
2. Check the current setting of Temp.
Controller providing the 4 – 20 mA
control signal to the Valve Actuator.
Readjust if necessary. If adjustment
does not clear fault, troubleshoot the
Controller.
3. Check Actuator U-bolt securing it to
Linkage Assembly. Tighten if needed
and readjust the CXT-E Control Valve
per Section 3.
4. If Valve still does not close after
checking the above items, disassemble
the Valve and clean the Seat per steps
CM18 – CM28 in Section 8. Readjust
the CXT-E Control Valve per Section 3.
T3 System
outlet
water
temperature is below
desired setpoint
CAUTION
Over-tightening the Pack-
ing Nut may trap the
Valve Stem and slow or
stop Valve motion.
1. Temp. Controller not
properly set.
2. Control Valve not
opening properly.
1. Check the current setting of the Temp.
Controller. If the setting is below the
desired setpoint, readjust as necessary.
2. Check as follows:
a. Ensure Actuator is secured to
Linkage Assembly. Tighten if needed
and readjust the CXT-E Control
Valve per Section 3.
b. Verify that 24 VDC power and 4 – 20
mA control signal are present at
Actuator pins 2 and 3 respectively.
c. To ensure Valve is not binding,
check Seal Retainer per steps CM1-
CM10 of Section 8 Corrective
Maintenance. Replace items as
necessary.