SmartPlate EV Installation, Operation and Maintenance Manual
CHAPTER 7
– TROUBLESHOOTING
OMM-0147_C
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TABLE 7-3. Troubleshooting Guide for Temperature Control Issues
No.
Observation
Probable Cause
Corrective Action
T-1
Too many valve
oscillations or too wide
outlet temperature
oscillation at low flow
Low flow condition may be
unsteady or at a critical
value for the control
system.
Increase the Proportional value (Pb
and/or Pb2). Note: This may cause
wider temperature deviation with
change in domestic flow.
T-2
Too wide of a deviation in
outlet temperature when
domestic flow changes
Dynamic loop response
time variation from the
engineering development
system. Many factors
contribute to this type of
dynamic system variation.
Decrease the Proportional value (Pb
and/or Pb2).
Note:
This may increase oscillations at
low flow.
T-3
On decrease in flow,
outlet temperature initially
goes up but then under-
shoots setpoint too much
before coming to setpoint
Dynamic loop response
time variation from the
engineering development
system. Many factors
contribute to this type of
dynamic system variation.
Increase Proportional (Pb or Pb2) first.
T-4
On increase in flow, outlet
temperature initially goes
down but then overshoots
setpoint too much before
coming to setpoint
Dynamic loop response
time variation from the
engineering development
system. Many factors
contribute to this type of
dynamic system variation.
Increase Proportional (Pb or Pb2) first.
T-5
After a change in domestic
flow, outlet temperature
remains too far from
setpoint for too long
Dynamic loop response
time variation from the
engineering development
system. Many factors
contribute to this type of
dynamic system variation.
Decrease Proportional and/or decrease
Integral (I1 and/or I2).
Note:
This may increase outlet
temperature oscillations at lower flows.
T-6
Over-temperature alarm or
water temperature more
than 10°F above the
setpoint after a long period
of non-usage.
Control valve not closing
fully, allowing some hot
boiler water to enter the
heat exchanger without
demand
Recalibrate the valve stroke using the
auto-calibration method described in
Chapter 4, section 4.2.1.
