AERCO Electronic Controls System (ECS) - Manual (Page 45)

Electronic Control System (ECS) and Type CXT-E Valve
7. TROUBLESHOOTING
VD2: 02/28/14 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288 Page 45 of 82
AC-105 OMM-0003_0D
Table 7-2. Troubleshooting – Electronic Control System (ECS)- Continued
NO. FAULT INDICATION PROBABLE CAUSE CORRECTIVE ACTION
T9
Over-Temp. Alarm
condition cannot be
cleared.
Over-Temp Switch
displays erroneous
temperature readings
1. Shorted Outlet
Temp. Sensor.
2. Defective Over-
Temp. Switch
3. A “No-Flow”
condition caused a
gradual buildup of
heat to the water in
vessel.
4. External
recirculation pump
shut off or failed.
1. Replace Outlet Temp, Sensor.
2. Replace Over-Temp Switch.
3. Open heater outlet to see if fault
clears. If there is no flow through
heater, go to Probable Cause 4.
4. Check pump to ensure it is turned on
and functioning properly. Also, check
for blockage in the incoming flow.
T10
Over-Temp. Alarm
condition occurs when
doing an initial startup.
Starting system after
being shut down without
following proper initial
start-up procedure.
Refer to Section 4 (Operation) for
starting system after being shut down.
See Pre-Operational Checks and Initial
Start-Up on page 4-1 and follow
instructions (OP1–OP10).
T11
Outlet water temp. far
below Setpoint
1. Incorrect Temp
Controller setting
2. Defective Temp.
Controller.
3. Linkage not properly
connected.
4. Defective Actuator.
5. Control Valve shaft
may be binding
1. Refer to Section 3 and check the
current setting of Over-Temp. Switch.
Readjust if necessary.
2. Disconnect cable plug from Valve
Actuator and verify that the Temp.
Controller is generating a control
signal greater than 4 mA. If not
replace Temp. Controller.
3. Check Control Valve Linkage and verify
it is properly connected and the pin in
the Linkage is in the correct position
for the Valve size being used.
4. Replace Valve Actuator.
5. Refer to Table 7-1, Fault T3, Corrective
Action 2c and perform the steps
indicated.
T12
Wide fluctuations in
outlet water temperature
during large flow
changes. Flow Sensor output
signal too low for flow
changes. Defective or
clogged Flow Sensor.
Under large changes in flow, the Flow
Sensor output should vary from 0 to 5
VDC. Check the signal level at TB-1 lead
113 to ensure it varies with flow changes.
If not, clean or replace Flow Sensor.