Form I-RA/D 140/235 (Version A), Page 34
General
Service
Reznor
®
used-oil-fired heaters have been designed and manufac
-
tured to provide years of trouble free operation.
However, as with any type of mechanical equipment, it can mal
-
function. For your safety, we suggest that if you are unfamiliar
with servicing this type of equipment, contact a qualified service
person. The material contained in this section is prepared to aid
an experienced service person in diagnosing and repairing Reznor
Model RA/RAD used oil heaters.
How a Reznor
®
Model RA/RAD Used-
Oil-Fired Heater Operates
When service is necessary, it is always helpful to understand the op-
eration of the device being serviced. With this in mind, the following
information has been prepared. Because of the many unique features
of the heater, we as the designer and manufacturer believe that it
will be worth your time to read this information before beginning any
service function.
The RA/RAD heaters differ from most residential and commercial oil
furnaces and used oil heaters in that the oil pump meters the volume
of oil supplied to the burner. A constant volume of oil is delivered by
the pump to the burner regardless of the oil viscosity. Oil pressure at
the outlet of the pump will vary depending upon oil grade, the length
and height of the supply line, and the oil temperature.
If a pressure in excess of 50 psi is experienced at the pump, a relief
valve will open and return the oil to the supply tank.
Oil pressure at the atomizing nozzle will vary from .25 psi to 4 psi
depending on the type of oil being burned. Nozzle oil pressure is not
critical because compressed air is used to atomize the oil.
The solenoid valve located adjacent to the burner housing performs
two tasks. The primary task is to prevent oil from flowing into the
combustion chamber due to oil expansion in the heater. The second
task is to assist in preventing oil from flowing backwards. Both the
solenoid valve and the pump motor are turned on and off by the ignition
controller. The check valve at the pump prevents backwards flow of
oil in both the heater supply line and the suction line to the pump.
To properly atomize the different types of used oil, the oil must be
heated. The oil flows through an aluminum heat exchanger (pre-heat
-
er) with a 300 watt heating element. This oil heater which is external
to the burner preheats the oil to approximately 175°F. A pair of 30
watt heating elements on the fuel line and nozzle assembly within the
burner maintain an oil atomizing temperature of 160°F. Temperature
sensors prevent burner operation until the proper temperatures are
attained. Oil temperature is maintained continuously as long as the
electrical power is on to the heater.
General
Operation
Service Notes
