Reflect-O-Ray
®
EDS 6
Installation, Operation & Service
Combustion Research Corporation
ELECTRICAL WIRING CRITERIA
WARNING
ELECTRICAL SHOCK
DANGER OF SEVERE INJURY
OR DEATH
Field wiring to the heater and vacuum exhauster must
be connected and grounded in accordance with
national, state, provincial, local codes and to the
guidelines outlined in this manual. In the United States
refer to the most current revisions to the National
Electric Code and in Canada refer to the most current
revisions to the Canadian Electric Code Part I
Standard.
DO NOT
use unless electrical wiring complies with all
applicable codes.
DO NOT
wire without providing for a power source
disconnect at each burner assembly and the Vacuum
Exhauster.
The requirements and practices described below are
based on the National Electrical Code ANSI/NFPA No. 70-
(latest edition) and the Space Heating Standard or the
Underwriters Laboratories, Inc. (UL), the Canadian
Electrical Code CSA C22.1 Part 1 (latest edition) apply in
Canada. Although UL & CSA requirements are uniform
throughout the country, local electrical codes may deviate
from these codes, therefore local inspection authorities
should be consulted regarding local requirements.
After final assembly and before shipping, each
Reflect-O-
Ray
®
EDS 6
burner must pass a 500 volt minimum
dielectric test.
VACUUM EXHAUSTERS
Safety control circuits must be a two-wire, with ground,
and have a nominal voltage not exceeding 125 volts. A
safety control or protection device must be connected so
as to interrupt the ungrounded conductor.
BURNERS
Safety control circuits must be two wire and have a
nominal voltage not exceeding 24 volts. The control circuit
shall be connected to a power supply branch circuit fused
at not more than the value appropriate for the rating of any
control or device included in the circuit.
Large enough wire must be used in connecting a
Reflect-
O-Ray
®
EDS 6
system. This is necessary for two reasons
- carrying capacity, and voltage drop. The wire size
necessary to provide carrying capacity without overheating
is generally determined by the electrical code which
specify a minimum wire size for the amperage used.
These requirements are intended to prevent overheating
and take no account of the length of wire. Most problems
have been caused by voltage drop due to long runs, or low
voltage furnished by the utility.
In order to assure proper operation of the electrical
components of the
Reflect-O-Ray
®
EDS 6 system
, it is
essential that the voltage to the exhauster motor and
burner controls is sufficient. It must be within 10 percent
of the nameplate rating under all conditions to assure
satisfactory operation. It is preferable that it be within 5
percent. Almost all complaints of motor not starting or not
reaching operating speed are caused by low voltage
reaching the motor. This voltage is dependent upon three
things:
1. The voltage furnished by the Power Company.
2. The size (gauge) of the electrical wiring to the motor.
3. The length of the wiring.
Warning Do not use 277 volt.
When supplying single phase from a three-phase system,
use a suitable sized machine tool transformer to transform
the 460V or 230V three-phase to 230V or 115V single
phase. Under no circumstances use 277V single phase
input to the
Reflect-O-Ray
®
EDS 6
system. The resulting
output from a two-to-one transformer would be 138V
single phase. These high voltages exceed the allowable
10% voltage variation from the normal and will damage
the electrical components, such as the 24V transformer,
control valve and exhauster motors of the
Reflect-O-Ray
®
EDS 6
system.
BURNER GROUNDING
It is necessary for the circuit ground, (L2) and chassis
ground to be common and maintained to an earthen
ground rod using copper (not aluminum) ground wires
throughout. Do not assume ground continuity to an earth
ground via gas piping, burner tubes, electrical conduits or
building structural steel. These should not be assumed as
proper positive earth grounds.
Burner Wiring -
Use minimum 18 Ga., 2 Conductor
Control Cable for wiring between control transformer
and burner
. The low voltage wiring on the secondary or
the transformer includes two wires for each burner. A third
grounding wire may be necessary for connection of burner
chassis to a good earth ground. Do not use control circuit
completion connections in this ground circuit.
The correct size wire should be carefully selected before
the installation is made. The first step is to establish what
voltage will be coming into the building. This will vary
throughout the country and must be determined locally by
checking with your power company and using experience
gained with other installations in your geographic area.
Once the minimum voltage available is established, you
will know how much voltage drop can be permitted in the
wiring. The following chart shows maximum wire lengths
(one way, not the length back and forth) to keep voltage
drop to a minimum of 10 percent at various cur rents at
115V.
The lengths shown in the following chart should never be
exceeded and in many cases it will be necessary to
reduce them to accommodate low voltage supplied to the
building. If 5 percent voltage drop is desired, the lengths
will be one-half of those shown. Permissible lengths for
other voltage drops will be in the same proportion, i.e., 8
percent = 80 percent of length shown, etc.
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