Chromalox SDRA-RG - Manual (Page 2)

2
IMPORTANT INSTRUCTIONS
When using electrical appliances, basic precautions should always be
followed to reduce the risk of fire, electric shock and injury to persons,
including the following:
1. Read all instructions before using this heater.
2. This heater is hot when in use. To avoid burns, do not let bare skin
touch hot surfaces. If provided, use handles when moving this
heater. Keep combustible materials, such as furniture, pillows,
bedding, papers, clothes, and curtains at least 3 feet (0.9m) from
the front of the heater and keep them away from the sides and rear.
3. Extreme caution is necessary when any heater is used by or near
children or handicapped individuals and whenever the heater is left
operating and unattended.
4. Always disconnect heater when not in use.
5. Do not operate any heater with a damaged cable or plug or after the
heater malfunctions, has been dropped or damaged in any manner.
Return heater to authorized service facility for examination, elec-
trical or mechanical adjustments, or repair.
6. Do not use outdoors.
7. This heater is not intended for use in bathrooms, laundry areas and
similar indoor locations. Never locate heater where it may fall into
a bathtub or other water container.
8. Do not run cord under carpeting. Do not cover cord with throw
rugs, runners or the like. Arrange cord away from traffic area and
where it will not be tripped over.
9. To disconnect heater, turn thermostat off, then remove plug from
outlet.
10. Connect to properly grounded outlets only.
11. Do not insert or allow foreign objects to enter any ventilation or
exhaust opening as this may cause an electric shock, fire or dam-
age the heater.
12. To prevent a possible fire, do not block air intakes or exhaust in any
manner. Do not use on soft surfaces, like a bed, where opening
may become blocked.
13. A heater has hot and arcing or sparking parts inside.Do not use it
in areas where gasoline, paint, flammable liquids are used or
stored.
14. Use this heater only as described in this manual. Any other use not
recommended by the manufacturer may cause fire, electric shock
or injury to persons.
15. This heater is not intended for use with an extension cord.
16.
SAVE THESE INSTRUCTIONS.
WIRING
ELECTRIC SHOCK HAZARD. Disconnect all power
before installing or servicing heater. Failure to do so
could result in personal injury or property damage.
Heater must be effectively grounded in accordance
with the National Electrical Code, NFPA 70.
1. Use heater only on the voltage and frequency specified on the
nameplate.
2. All wiring should be done in accordance with local codes and the
National Electrical Code by a qualified person.
3. Branch circuit wire for connection to heater must be at least
90˚C wire.
4. The top access panel is secured by 4 screws that must be loosened
to gain access.
5. A ground terminal is provided near the power terminal board.
The ground wire should be connected before other connections
are made.
6. Refer to Table A for proper size “SO” grade of cable.
7. A proper strain relief must be used with “SO” grade cable.
8. Dragon heaters are factory pre-wired for 3-phase delta operation.
Some units can be converted to single phase operation by chang-
ing the wiring. The appropriate wiring diagram is also located on
the back of the wiring compartment cover.
Cord Preparation for Chromalox Portable Heaters
1. Determine the gage and number of conductors from the tabulation
below using amps and phase from the heater nameplate. It is not
recommended that cord exceed 50 feet in length.
Model Number Volts kW Phase Amps Min Wire Size
SDRA-30-43 480 30 3 37.2 6 Ga
SDRA-30-63 600 30 3 30.0 8 Ga
SDRA-48-43 480 48 3 58.9 4 Ga
SDRA-48-63 600 48 3 47.3 4 Ga
SDRA-60-43 480 60 3 73.3 2 Ga
SDRA-60-63 600 60 3 58.9 4 Ga
SET-UP AND OPERATION
The SDRA SuperDragon is designed to be used with 20” diameter
flexible duct. A feature of the heater is that the fan speed can be easily
adjusted from 1500 to 2300rpm, (SDRA heaters are shipped from the
factory with the fan speed set at 1800 rpm). The maximum external
static load for the blower is .38” H
2
O, regardless of the fan speed
selected. The outlet temperature is controlled by a built-in thermostat-
ic control; the maximum outlet temperature is a function of the kW rat-
ing and the amount of air (cfm) flowing through the heater. The addi-
tion of flexible duct will provide additional static load, resulting in a
lower cfm, the lower air flow will reaise maximum outlet temperature
until the static load reaches .38”H
2
O. Exceeding the maximum static
load will result in the tripping of the overtemperature control. The per-
formance range of the SDRA units is as shown in table B.
The motor and fan have variable pitch pulleys for changing the air
flow and the ΔT. Graphs 1, 2 and 3 provide the performance data for
each size heater at the recommended minimum, medium and maxi-
mum fan speeds. The curves end at the point where the .38” H
2
O stat-
ic load has been reached. The temperature rise is based on using
Chromalox 20” diameter FX-20 flexible duct. The performance curves
were determined by actual testing; therefore using flexible duct not
supplied by Chromalox may vary the results. The introduction of bends
in the ducting will add static load equivalent to adding 15 feet of duct
length for each 90˚ bend and 25 feet of duct length for each 180˚ bend.
Δ T Max. ΔT at Max.
kW Fan RPM CFM No Load Static Load Static Load
30 1800 2200 42˚F .38” H
2
O 86˚F
48 1800 2200 68˚F .38” H
2
O 144˚F
60 1800 2200 88˚F .38” H
2
O 170˚F
Table A
Table B