Operation
3-2
750-204
Profire D/LND
3.1.1 — Oil Flow
Light Oil: Refer to the piping diagrams. Open all valves in the oil suction and return lines. The burner oil meter-
ing units are not capable of creating suction. Fuel oil must be supplied to the metering unit at a nominal 10 to
15 PSI pressure by a circulating supply pump.
Heavy Oil: Refer to the piping diagrams for burners using heavy oil. Note the bypass valve between the supply
and return lines. At initial system startup or after prolonged shutdown, start the system as follows:
1. A vacuum (or compound pressure-vacuum) gauge should be installed in the oil suction line, and its reading
noted. This gauge indicates the tightness of the suction system.
2. Open valve No. 1 in the bypass line and close valve No. 2 in the supply line to the metering pump.
3. Turn on the pre-heater and the circulating pump. Oil will circulate from the tank through the circulating pump
and pre-heater, returning to the tank through the bypass and return lines. Observe the oil supply pressure
gauge for indication that oil flow is established. If no pressure shows after a few moments, and the vacuum
gauge shows little or no suction, stop the circulating pump and re-prime. heavy oil in the storage tank (hot
well) must be warm enough to permit flow.
4. As the system becomes warm, the pressure required for circulation will gradually drop. When the return is
warm, open No. 2 valve and throttle the flow in the bypass line with valve No. 1. This will cause the oil to
flow through the back pressure valve to the tank via the return line. The pressure in this loop around the
burner should not exceed 25 PSI. When the loop around the burner becomes warm, gradually close valve No.
1 in the bypass line. All supply oil will then flow through the burner loop.
3.1.2 — Oil Pressure
The system pressure is regulated by the back pressure valve. This should be set between 10 to 15 PSI (DL & DM
Models) or 12 to 20 PSI (DE Models) at the burner inlet after the temperature stabilizes.
3.1.3 — Oil Temperature
Heavy oil flow and burning characteristics are dependent on oil viscosity, which in turn requires temperature reg-
ulation. A loop heater in the supply line between the circulating pump and the burner heats the oil. The loop
Boiler Check the boiler water level. Be sure all boiler valves are installed correctly and posi-
tioned properly. Set the high limit control slightly above the desired temperature. Set
modulating controls at the desired temperature or pressure.
Firing Preparations for
Oil Burners
Prior to initial firing, oil flow pressure and temperature should be verified.
Inspect the compressor lube oil sump level. Add oil to bring the oil level to the midpoint
or slightly higher in the reservoir sight glass. Make certain that the drive belts or couplings
are aligned and properly adjusted.
To verify air flow and pressure, momentarily flip the switch “ON” and immediately turn it
“OFF.” The programmer will continue through its cycle, however, without ignition or ener-
gizing the fuel valves. Observe the air pressure gauge. With the compressor running and
no oil flow, the pressure should be approximately 10 PSI. The schematic flow diagrams in
Chapter 1 indicate the flow of fuel and atomizing air.
If the burner is a duel fuel model, make certain that the main gas shut off cock is closed
and the fuel selector switch is set to “OIL.”
Component Description
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