IC-SA-1511 (02/2014)
V/LNV Series Manual
1-9
Introduction
FIGURE 1-8.
Full Modulation Oil System with a Remote Pump (V60-168)
1.6.2 — Operation
Fuel oil is delivered to the fuel pump, either by gravity, fuel pump suction, or by a circulating pump, through
a fuel oil filter. Pressurized fuel returns to the storage tank until the two solenoid valves open. Straight oil
burners (VL13-55) employ direct spark ignition where the oil is ignited when the oil solenoid valves open
and the spray contacts the electrical discharge from the direct spark electrodes.
Gas-oil VLG burner use a proven gas pilot where the oil is ignited when the oil solenoid valves open and the
oil spray contacts the established gas pilot flame.
On full modulation units, the modulating actuator varies the oil metering valve setting. The metering valve
located in the return oil loop reduces the firing rate by opening and allowing more oil to return to the supply
tank. Conversely, at high fire, the valve is closed, forcing all oil to exit the spray nozzle.
On LHO/LHL units, bypass piping routes most of the oil back to the storage tank while at low fire. At high
fire, a valve blocks the return loop and forces all the oil through the nozzle.
1.7 — Gas Handling System
Gas is introduced into the combustion zone from a circular manifold through multiple ports in the manifold.
Firing rate is determined by the size and number of ports, by manifold pressure, and by combustion zone
pressure. The firing rate is regulated by a rotary, butterfly-type throttling valve at the manifold inlet. The
valve is actuated by adjustable linkage from the modulating motor. Depending upon specific requirements,
one or two gas safety shutoff valves are provided for installation in the gas train upstream of the butterfly
OIL
NOZZLE
OIL
PRESSURE
SWITCH
N.C.
VALVES
FUEL UNIT
PRESSURE TAP
MODULATING
MOTOR
OIL RETURN
TO TANK
OIL
SUPPLY
OIL
METERING
VALVE
REMOTE FUEL
UNIT
OIL SUPPLY
TO NOZZLE
656-10211-000