12
7. TROUBLESHOOTING AND MAINTENANCE
WARNING:
DO NOT ATTEMPT TO REPAIR THE BDM-250; IT CONTAINS NO
USER-SERVICEABLE PARTS. IF TROUBLESHOOTING METHODS FAIL, PLEASE RETURN THE
BDM-250 TO YOUR DISTRIBUTOR FOR MAINTENANCE.
WARNING:
NEVER DISCONNECT THE DC WIRE CONNECTORS UNDER LOAD. ENSURE THAT
NO CURRENT IS FLOWING IN THE DC WIRES PRIOR TO DISCONNECTING. AN OPAQUE
COVERING MAY BE USED TO COVER THE MODULE PRIOR TO DISCONNECTING
WARNING:
ALWAYS DISCONNECT AC POWER BEFORE DISCONNECTING PV MODULE WIRES
FROM BDM-250. THE AC CONNECTOR OF THE FIRST BDM-250 IN A BRANCH CIRCUIT IS
SUITABLE AS A DISCONNECTING MEANS ONCE THE AC BRANCH CIRCUIT BREAKER IN THE LOAD
CENTER HAS BEEN OPENED.
WARNING:
BDM-250 IS POWERED BY DC POWER FROM PV MODULES. MAKE SURE YOU
DISCONNECT THE DC CONNECTIONS AND RECONNECT DC POWER TO WATCH FOR THE TWO
SECONDS LED ON AND TWO SECONDS LED OFF AFTER DC IS APPLIED.
LED indica
�o
n
o
f err
o
r
●
Err
o
r rep
o
rt: AC
o
r DC fault
The LED light is on by 4 second, and o
ff
by 4 seconds.
●
Err
o
r rep
o
rt: GFDI fault
The LED light stays on.
Tr
o
ublesh
oo�
ng an in
o
perable BDM-250
To troubleshoot an inoperable BDM-250, follow the steps in the order shown:
1. Check the connec
�
on to the u
�
lity grid. Verify that the u
�li
ty voltage and
frequency are within allowable ranges shown in the label of BDM-250.
2. Verify u
�li
ty power is present at the inverter in ques
�
on by removing AC, then DC
power. Never disconnect the DC wires while the BDM-250 is producing power.
Re-connect the DC module connectors, and then watch for the LED blinks.
3. Check the AC branch circuit interconnec
�
on harness between all the BDM-250.
Verify that each inverter is energized by the u
�
lity grid as described in the
previous step.
4. Make sure that any AC disconnects are func
�
oning properly and are closed.
5. Verify the PV module DC voltage is within the allowable range shown in the label
of BDM-250.
6. Check the DC connec
�
ons between the BDM-250 and the PV module.
7. If the problem persists, please call customer support at NEP.
WARNING:
DO NOT ATTEMPT TO REPAIR THE BDM-250; IT CONTAINS NO
USER-SERVICEABLE PARTS. IF TROUBLESHOOTING METHODS FAIL, PLEASE RETURN THE
BDM-250 TO YOUR DISTRIBUTOR FOR MAINTENANCE.
Disc
o
nnec
�
ng a BDM-250 fr
o
m the PV M
o
dule
To ensure the BDM-250 is not disconnected from the PV modules under load, adhere
to the following disconnec
�
on steps in the order shown:
1. Disconnect the AC by opening the branch circuit breaker.
2. Disconnect the
fi
rst AC connector in the branch circuit.
3. Cover the module with an opaque cover.
4. Using a DC current probe, verify there is no current
fl
owing in the DC wires between
the PV module and the BDM-250.
5. Care should be taken when measuring DC currents, most clamp-on meters must be
zeroed
fi
rst and tend to dri
�
with
�
me.
6. Disconnect the PV module DC wire connectors from the BDM-250.
7. Remove the BDM-250 from the PV array racking.
Installing a replacement BDM-250
1. A
�
ach the replacement BDM-250 to the PV module racking using hardware
recommended by your module racking vendor. If you are using grounding washers
(e.g., WEEB) to ground the chassis of the BDM-250, the old grounding washer should
be discarded, and a new grounding washer must be used when installing the
replacement BDM-250. Torque the BDM-250 fasteners to the values listed below:
1/4” moun
�
ng hardware – 45 in-lbs minimum
5/16” moun
�
ng hardware – 80 in-lbs minimum.
2. If you are using a grounding electrode conductor to ground the BDM-250 chassis,
a
�
ach the grounding electrode conductor to the BDM-250 ground clamp.
3. Connect the AC cable of the replacement BDM-250 and the neighboring BDM-250
to complete the branch circuit connec
�
ons.
4. Complete the connec
�
on map and connect the PV Modules.
1) Complete the connec
�
on map
2) Each BDM-250 has a removable serial number located on the individual label.
Enter the unique address contained in part of this serial number into a BDG-256,
and correspond it to a number in the connec
�
on map.
3) Connect the PV Modules
4) Completely install all BDM-250 and all system inter-wiring connec
�
ons prior to
installing the PV modules.
a) Mount the PV modules above their corresponding BDM-250. Each
BDM-250 comes with two oppositely sexed DC connectors.
b) First connect the posi
�v
e DC wire from the PV module to the posi
�v
ely
marked DC connector (male pin) of the BDM-250. Then connect the nega
�v
e
DC wire from the PV module to the nega
�v
ely marked DC connector (female
socket) of the BDM-250. Repeat for all remaining PV modules using one
BDM-250 for each module.
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