SmartPlate Installation, Operation & Maintenance Manual
CHAPTER 7
– TROUBLESHOOTING
OMM-0069_0H
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TABLE 7-2. Troubleshooting
– Electronic Control System (ECS/SP)
No.
Fault Indication
Probable Cause
Corrective Action
T6
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. 3-Way Control Valve
not closing fully during
no-load conditions.
4.
A “No-Flow” condition
caused a gradual
buildup of heat to the
water in vessel.
5. Water Heater
recirculation pump
shut off or failed.
1. Replace Outlet Temp, Sensor.
2. Replace Over-Temp Switch.
3. Calibrate 3-Way Control Valve per section
4.2.1.
4. Open hot water valve at sink or tub outlet
to see if fault clears. If there is no flow
through heater, go to Probable Cause 5.
5. Check recirculation pump to ensure it is
turned on and functioning properly. Also,
check pump fuse on side of Control Box.
T7
Outlet water temp. far
below Setpoint
1. Incorrect Temp
Controller setting
2. Defective Temp.
Controller.
3. Heat exchanger
fouled on Boiler Water
side.
4. Defective Control
Valve Actuator
5. Boiler water supply
temp. is too low.
6. Boiler Failure
1. Refer to Chapter 4 and check the current
setting of Over-Temp. Switch. Readjust if
necessary.
2. Remove the cover from the Electronics
Module of the Control Valve and verify that
the Temp. Controller is generating a
control signal greater than 0 VDC. If not
replace Temp. Controller.
3. Clean Boiler Water Inlet Strainer.
Clean heat exchanger.
4. Replace Valve Actuator (SEE TABLE 7.1)
5. Increase boiler water temperature.
6. Check operational status of Boiler.
T8
Wide fluctuations in outlet
water temperature during
large flow changes.
1. Water Heater
Recirculation Pump
not operating.
2. Boiler water temper-
ature drops below
DHW setpoint during
heavy demand, then
recovers.
3. Boiler water temper-
ature drops below
DHW setpoint but
does not recover until
load is reduced.
4. Boiler water supply
temperature is too
high.
1. Check Control Box fuse and power to
pump.
2. Install Boiler Water Buffer Tank to provide
hot water reservoir for the Water Heater to
draw from during large load swings.
3. The boiler water supply is under-sized.
Add more boilers or reduce DHW usage.
4. Control Valve is not seating properly. See
Chapter 4 and auto-stroke valve.