Syn-Tech Systems FuelMaster FMU-2500 Classic Installation Manual page 90

f. Controlling DC Devices (Hose Reels in Lube Bays/Bulk Oil Dispensers).
Whenever a part is field modified, mark/label it to inform others of the modification so a replacement part
may be modified in the same manner. Make Syn-Tech aware of the modification when ordering a
replacement part.
Some minor modifications are necessary when controlling DC devices such as solenoid valves for
hose reels in lube bays, or bulk oil dispensers. Control is similar to the method described in
Controlling Valves. Power to the solenoid valves is switched. These applications often do not
contain their own power source. A power supply must be added to power the solenoid valve, and
pulsers or flowmeters must be added to receive quantity outputs from the device.
If the added power supply is DC voltage, it is recommended a Dual Control Relay Assembly (DCRA)
be used. DCRA can switch high or low, and AC or DC voltages. Use caution in selecting the
application. DCRA cannot work with loads in excess of 2 amps.
If a Solid State Relay Assembly (SSRA) is used, it must have AC solid state relays (SSRs) replaced
with DC solid state relays. In addition, the polarity of the DC solid state relay switch contacts varies
from that of the AC solid state relays. LN inputs and LD outputs are reversed to LD inputs and LN
outputs on hose positions A, D, E, and H. See the table below:
Cutting just one leg of the 75K ohm resistors at positions R92-R99, and positions R80-R87, retains the
resistor for reconnection should it become necessary. Only cut the resistors in the positions being used
for DC control. Example: if DC control is being used only in hose position A, cut the resistors at R92 and
R80.
In all cases of DC control, AC pump handle detection must be disabled, and may be disabled for
individual hose positions. This is done by cutting one leg of the 75K ohm resistors at applicable
positions R92-R99, and R80-R87 on the Pedestal I/O Board (see Figure 4-14 for resistor
locations). When the AC pump handle detect resistors are cut, the PHS positions on terminal
TB3 may be used to land DC common (ground). A single DC common input may be attached to
one of the altered PHS positions, and jumpers may be added to connect DC common to other
altered PHS positions.
FuelMaster
®
Table 4-2. Pedestal I/O Board Inputs/Outputs
for AC and DC Solid State Relays (SSRs)
Hose AC
Position SSR
A In LN
A Out LD
B In LN
B Out LD
C In LN
C Out LD
D In LN
D Out LD
Installation Manual
NOTE
DC Hose
SSR Position
LD E In
LN E Out
LN F In
LD F Out
LN G In
LD G Out
LD H In
LN H Out
NOTE
88
AC DC
SSR SSR
LN LD
LD LN
LN LN
LD LD
LN LN
LD LD
LN LD
LD LN