Burner Operation and Control
2-12
750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
2.6 — Additional Controls for Heavy Oil
The oil heater is provided to heat heavy oil to the point where it can be effectively atomized and burned. Most
heavy oil heaters utilize an electric heater to reduce the viscosity of the heavy oil until steam or hot water is available
to the oil heater shell.
Heavy oil heaters, operating with hot water, will have additional controls.
Component Description
Heater Switch Manually provides power to the oil heater system.
Oil Heater (electric) Used for heating sufficient fuel oil for low-fire flow during cold
starts before steam or hot water is available for heating. The heater
must be turned off during extended boiler lay-up, or at any time the
fuel oil transfer pump is stopped.
Electric Oil Heater Thermostat Senses fuel oil temperature and energizes or de-energizes the elec-
tric oil heater to maintain required temperature of the fuel oil.
Steam Oil Heater Thermostat Senses fuel oil temperature and controls the opening and closing of
the steam heater valve to maintain the required temperature of the
fuel oil.
Oil Heater Shell (steam/hot water) Heats fuel oil through medium of steam or hot water. Electric
heater is housed in the steam heater, but is housed separately on a
hot water heater. Steam oil heaters on 15 psi boilers operate at boiler
pressure. Steam oil heaters furnished on high pressure boilers are to
be operated at less than 15 psi. Operation is accomplished with a
steam pressure regulator valve.
Oil Return Excess oil returned to the heavy oil supply tank.
Oil Inlet From Supply Tank Heavy oil inlet from the supply tank.
Steam Heater Check Valve Prevents oil contamination of the waterside of pressure vessel
should any leakage occur in the oil heater.
Steam Trap Drains condensate and prevents loss of steam from the steam oil
heater. Condensate must be piped to a safe point of discharge.
Check Valve (steam heater discharge) Prevents air entry during shutdown periods when cooling action
may create vacuum within steam heater.
Steam Heater Pressure Regulator Adjust to provide reduced (usually less than 15 psi) steam pressure
to the heater to properly maintain the required fuel oil temperature.
The regulator and the pressure gauge are not furnished on 15 psi
units.
Steam Heater Solenoid Valve A normally open solenoid valve opened by the steam oil heater ther-
mostat to allow flow of steam to the steam heater to maintain tem-
perature of fuel oil.
Steam Pressure Gauge Indicates steam pressure entering the heater.
Oil Relief Valve allows release of excessive pressure to the return side of the oil line
piped to the tank.
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