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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 Problem
Solution
ER1
On Display
The Safety High Limit of 250
°
F, has been
reached
1- Check to see if water is dripping on the sensor.
2- Reduce the Hi setting (and/or) ensure that there is
proper water circulation in the system.
ER2
On Display
Water Probe… The water probe is transmitting
an invalid signal. Closed circuit.
Check wiring
ER3
On Display
Water probe…Sentry is sensing an open circuit
at water probe. Or, the wiring to the outdoor
probe is grounding.
Check wiring. (Note: ER3 will be displayed if
temperature sensed is less then 32
°
F.)
Note: If problem is corrected by resetting power, Sentry
control had locked-up; contact NY Thermal.
ER5
On Display
DHW
Problem
The control has determined an Indirect water
heater problem, the boiler has cycled off 10 times
during a single call for domestic. The Indirect call
will now be ignored until power is reset or the
indirect call is interrupted.
((Not activated on Combi version))
1-Not enough flow to keep boiler from tripping on limit.
Verify that a min. of 6 GPM flow is going through boiler &
indirect circuit.
2- Reduce indirect Aquastat setting, or Increase
difference between (Lo Setting) and (indirect Aquastat
setting).
3- Indirect limit or wiring failure.
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)
2- Check for 24V between B on terminal block and F1 on
Sentry plug, if not present a limit has tripped (see wiring
diagram).
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.
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.
ASO
Indicates
that the Air
Switch is
Open
This is displayed when the boiler is expecting the
air switch to be closed by a differential pressure
generated when the combustion blower turns on.
It can occur momentarily during normal
operation. A problem is indicated when ASO is
displayed continuously.
1-Are the vinyl tubes connected between the air switch
and the ports on the inlet pipe. Negative side of switch
connects to the port on the 1-1/2 ABS elbow.
2-Check for blockage on the intake and exhaust vents.
3-If fan is running, air switch may be faulty.
4-If fan is not running, check 120V wiring to blower, if ok
remove low voltage harness from blower, if blower fails to
start, replace blower, if blower does start problem may be
with blower or Sentry control.
ASC
Indicates
that the Air
Switch is
Closed
This is displayed when the boiler has turned the
blower off and is expecting the air switch to be
open. It can occur momentarily during normal
operation. A problem is indicated when ASC is
displayed continuously.
1-Is the fan running. If so check for 24V between C and
D terminals (see wiring diagram). If 24V is not present
replace transformer.
2-Check venting termination with required venting
described in manual.
Ignition
Sequence
not
Check for 24 Volts between terminal B1 on
Sentry & Ground
1 – If there is 24V, indicates faulty wiring between BI and
W1 on Fenwal, or faulty Fenwal.
2 – If 24V is not present proceed to next step.
