31
10.0 TROUBLE SHOOTING
This section is intended to assist the service technician in detecting and correcting common errors. The Sentry 2100 is equipped with an
internal diagnostic system that verifies control operation. The following series of error codes has been developed to aid in diagnosing
control problems:
Problem Detected
Proble m
Solution
ER1
On Display
“Water Temperature
Excessive”
Sentry has sensed a water
temperature in excess of
250ºF at the Water
Sensor.
1 – If the boiler is extremely hot check for adequate water pressure and circulation,
contact NTI for assistance.
2 – If not hot, check for sources of grounding or shorting at the Water Sensor electrical
connections, check wiring from Sensor to Sentry Control.
3 – Replace Water Sensor if the resistance is not in the correct range. (See resistance
charts for 1 Mohm Trinity Thermister)
ER2
On Display
“Water Sensor Short
Circuit”
Sentry has sensed a short
circuit in the Water
Sensor circuit.
See ER1.
ER3
On Display
“Water Sensor Open
Circuit”
Sentry has sensed an open
circuit in the Water
Sensor circuit.
1 – Check wiring to Water Sensor for open circuits or shorting to ground. (Note: ER3
will be displayed if temperature sensed is less then 0
°
F.)
2 – Replace Water Sensor if the resistance is not in the correct range. (See resistance
charts for 1 Mohm Trinity Thermister)
ER4
On Display
“24V Limit Error”
Sentry has sensed a lack
of 24V on the outlet of the
Sentry burner relay (B1).
The error locks the boiler out for one hour before retrying ignition.
1 – Reset power, if error goes away the problem is intermittent and was likely caused by
a tripped limit that has automatically reset, check for adequate water pressure and flow
rate. Allow the boiler to cycle and verify proper operation including outlet water
temperature and flue temperature. If operation is unsuccessful and the error reoccurs:
2 – Ti100-200’s are equipped with a low water pressure switch on the boiler return that
requires a minimum of 10PSI to complete the 24VAC ignition circuit. Ensure there is a
minimum of 12PSI on the boiler outlet, prior to the primary circulator; ensure the boiler
is plumbed in primary-secondary fashion. Replace water pressure switch if plumbing
and pressure is correct and if it measures an open circuit.
3 – Ti400’s are equipped with a flow switch on the boiler outlet. Ensure the flow
switch is closing, if not check for proper flow rate.
4 – Check for continuity through the 24VAC limit wiring and manifold and stack limits,
replace limits or wiring that are not a closed circuit.
ER5
On Display
“DHW Time-Out”
The ER5 option is ON
and the Sentry has sensed
that the DHW call has
lasted longer then 2.5
hours, thus removing
priority from the DHW
call.
Reset the ER5 error by resetting the power or cycling the DHW call. Check for proper
operation of the DHW call.
1 – Combi’s are equipped with a DHW flow switch; ensure it is not sticking in the
closed position when there is no DHW flow. If so, remove it and free it of any debris
and check for proper operation, replace if necessary.
2 – For non-Combi boilers, operating with an indirect water heater, check for proper
boiler water circulation during a DHW call, and check for proper operation of the
indirect water heater’s Aquastat.
3 – For applications with prolonged DHW draws, turn the ER5 option OFF.
ER6
“Flame Lock Out”
Sentry has sensed a lack
of 24V to the gas valve
during operation or a
Fenwal ignition lockout.
1- There is a problem in the ignition sequence, it could be caused by a faulty igniter,
flame sensor, gas valve or improper line pressure or combustion. Check ignition
sequence to determine which component is not functioning.
(Sentry will retry ignition
sequence 1 hour after ER6 code originally occurs or if control is reset)
Reset calculation being
used to lower HI setting.
If OD probe is being used, the HI setting will be calculated using formula in Section 8,
adjust RES setting as necessary.
Burner shuts
off before
set-point
temperature
is reached
(and burner
light goes out)
Thermostat is satisfied
1-If the thermostat demand light is turning off, the thermostat has satisfied.
2-If DHW temp light is turning off; the aquastat or call for domestic has been satisfied.
ER9
Internal Controller
Indicates that the Sentry control has lost communication with an internal processor,
contact NTI for assistance.
Summary of Contents for Trinity Ti 100
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