Pump motor control relay (when provided)
Solenoid valve (when provided)
Pump motor (when applicable).
The following paragraphs in this section provide guidelines for wiring dispensers to VST Fuel S-810 systems. These
instructions should be followed as closely as possible for proper system operation. Functional descriptions
and drawings are provided in this section to assist installers with wiring data.
B. VST FUEL S-810 INTERFACE WIRING
1. Typical dispenser-to-VST Fuel S-810 field wiring diagrams are included in this section (see drawing). The VST
Fuel S-810 connections are shown in the drawing as they appear on the back of the VST Fuel S-810 with
the cover removed. (Installations may vary from this concept due to wiring codes and other circumstances.)
Wiring diagrams of dispensers are used as examples only and in no way imply that the units used with the
system must be rewired to conform with the drawings. Dispensers are shown in all drawings at the end of
fueling with the operating handle in the off position.
2. Install all interconnecting wiring using the most applicable local wiring codes and reliable installation methods.
Wire should be installed in rigid conduit buried in a trench. When planning wire runs, the following
specifications apply:
a. Use Table 1 and the National Electrical Code to determine size of conduit required for the
number
of conductors.
b. When possible, install at least 25 percent spares for expansion and maintenance.
CAUTION:
NEVER RUN AC OR OTHER EQUIPMENT WIRING WITH VST FUEL S-810 LOW-VOLTAGE WIRING
UNLESS IT IS IMPOSSIBLE TO AVOID SUCH WIRE RUNS. FAILURE TO COMPLY MAY CAUSE
MALFUNCTION OR POSSIBLE EQUIPMENT DAMAGE.
c. Never run ac or other manufacturers' equipment wiring with VST Fuel S-810 wiring unless it is
impossible to avoid such wire runs. In these cases, shielded cable with outside insulating sheath
must be used for low-voltage wiring. The shield must be grounded at one end only. Insulate the
ungrounded end to prevent shorting to conduit or other wiring.
Note: Shielded wire should be used only if authorized by the applicable electrical codes.
C. DISPENSER WIRING
1. One single-pole interpose relay is provided for each dispenser. Interpose relays are located inside at the rear of
the VST Fuel S-810 housing. (See Figures 4-8 for interpose relay wiring) Relay contacts are rated at 1/3 hp
(115 Vac @ 6 amperes, 230 Vac @ 3 amperes).
2. Terminals are provided at the rear of the VST Fuel S-810 for wiring connections to the control interpose relays,
for wiring connections to the pulse transmitters, and for wiring connections to the handle switches. A
three-wire 115/230 Vac, 50/60 Hz. line input is required for ac power to the VST Fuel S-810. Screw
terminals are located at the rear of the VST Fuel S-810 for the ac line connections.
VST, 2010
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