CSA RA 350, Installation Manual

Page: 35 / 60

Form I-RA/D 350/500, P/N 131090R12, Page 35
General
Service
Reznor
®
used-oil-fired heaters have been designed and manufactured
to provide years of trouble free operation.
However, as with any type of mechanical equipment, it can malfunc-
tion. For your safety, we suggest that if you are unfamiliar with ser-
vicing 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-fired heaters.
How a Reznor
®
Model RA/RAD Used-Oil-
Fired Heater Operates
When service is necessary, it is always helpful to understand the operation
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 fur-
naces 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 de-
pending 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 sup-
ply 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-heater) with either
a 650 watt (RA/RAD350) or a 770 watt (RA/RAD500) heating element.
This oil heater which is external to the burner preheats the oil to ap-
proximately 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