Power Supply Test - A.O. Smith 100 Series Service Handbook

POWER SUPPLY TEST

See Figure 21 on page 28 for location of the JP1 jumper and the power supply status LED lights on the PDB
circuit board shown below. This illustration is rotated 90° clockwise.
The upper right corner of the PDB contains three JP1 jumper pins, a two pin jumper and three power supply
status LED lights. With power applied the green DS2 LED should always be lit. The JP1 jumper pins and
jumper are used to activate a power supply test function.
POWER TEST PROCEDURE
Turn power off to the Boiler at the Boiler's on/off switch. Disconnect the wiring harness plugs at the J1, J2,
and J3 Sockets on the PDB. Remove the two pin jumper from JP1 pins 1 and 2 (normal setting) and place it
to short across JP1 pins 2 and 3 (power test setting). Turn power back on and note which of the three LEDs,
labeled DS1, DS2 and DS3 are illuminated. If the power supply is properly connected the Yellow and Green
LEDs (DS1 and DS2) should be illuminated and the red (DS3) LED should be off. If any other combination
of LEDs are illuminated refer to Table 6 below to determine the nature of the problem and what corrective
action must be taken.
NOTE:The two pin jumper should be in the "Run" (shorted across JP1 pins 1 and 2) position during normal
operation. Leaving the jumper in the test mode when operating the system may cause trouble with Ground
Fault Interrupters.
The wire harnesses that normally connect to J1, J2, & J3 should be disconnected while performing this test.
Power test results will not be accurate if these three wiring harness plugs are not disconnected during the
test procedure.
TABLE 6
LINE CONNECTION STATUS
Proper Connection
Open Ground
Reverse Polarity
Open Hot
Open Neutral
Reverse Hot & Ground
Hot wire on Neutral connect & Open
Neutral wire
DS1
Yellow
Test
3
2
Run
1
DS1 YELLOW LED
Servicing should only be performed by a Qualified Service Agent
DS2
Green
JP1
Figure 26
DS2 GREEN LED
ON
OFF
OFF
OFF
ON
ON
OFF
DS3
Red
DS3 RED LED
ON
ON
ON
OFF
ON
OFF
OFF
OFF
OFF
ON
OFF
ON
ON
ON
33