Switch Open; Control Bad; Combustion Air Blockage - A.O. Smith CYCLONE XHE BTH 300A Installation & Operating Instructions Manual

Display Flashes "05" when button is pressed:
Possible Cause
1. Temperature Probe wiring
open
2. Defective probe
Display Flashes "15" when button is pressed:
Possible Cause
1. No water in tank and tank
in freezing conditions
2. Water in tank above freezing
Display Flashes "25" when button is pressed:
Possible Cause
1. Water in tank is low, probe
immersed in steam
2. Probe wiring shorted
3. Defective probe
ECO SWITCH OPEN (Figure 21)
ECO LED Flashing:
ECO SWITCH OPEN, ECO LED Flashing
Possible Cause
1. This indicates the control has
failed on of its internal
diagnostic self-tests.
CONTROL BAD (Figure 22)
All LEDs Flashing:
Remedy
1. Repair Wiring
2. Replace probe
Remedy
1. The symptom does not
reflect a control problem
2. Temperature probe out of
tolerance, replace temp.
probe
Remedy
1. Fill tank
2. Repair wiring
3. Replace probe
FIGURE 21
Remedy
1. Press button on the
display board to reset
control. If this error
occurs repeatedly,
replace control.
CONTROL BAD, All LEDs Flashing
Possible Cause
1. Temp. Probe unplugged
2. Temp. probe wiring damaged
3. Water in tank too hot
COMBUSTION AIR BLOCKAGE (Figure 23)
Pressure Switch LED Flashing:
COMBUSTION AIR BLOCKAGE, Pressure Switch LED Flashing
Possible Cause
1. Combustion air blocked
2. Blower not operating:
a. Check blower wiring
b. Check blower motor
3. Defective air switch
4. Pressure switch jumped out
17
FIGURE 22
Remedy
1. Check connectors
2. Repair wiring
3. Normal condition when
water t e m p e r a t u r e
exceeds safety limit.
Allow water to cool or
admit water into tank and
manually reset the control.
Determine cause for
overtemp condition.
FIGURE 23
Remedy
1. Check exhaust piping and
flue for obstructions
2. a. Repair wiring
b. Replace blower motor
3. Replace air switch
4. This controller must sense
an open contact on the
blower proving airflow
switch before the blower
comes on. Check to see if
blower proving airflow
switch is still connected to
the unit.