Chromalox SDRA-30-43 User manual

1
PF499-4
161-304812-003
March 2019
Installation and Operation
Instructions
SDRA & SDRA-RG
Portable Industrial
Unit Blower Air Heater

2
Risk of fire. Do not use as a residential or household
heater.
Hazard of Fire or Discoloration of Temperature Sen-
sitive Fabrics. Do not use as a residential or house-
hold heater. Keep combustible material and such
fabrics away from heater. Do not operate heater
where flammable vapors, gases or liquids are pres-
ent. Heaters in the heat mode should not be oper-
ated in room temperatures above 130°F. Fan motor
is not designed to operate in ambients below -10°F.
To avoid personal injury read “IMPORTANT INSTRUC-
TIONS” on page 2 before installation or operation of
heater.
Keep electrical cords and combustible materials,
such as drapes and other furnishings, away from
heater.
Table 1 - Specifications
Model
Electrical Data (60 Hz) Dimensions (In.)
Volts kW Phase Amps* 1/3 PH BTU Height Width Depth
SDRA-30-43 480 30 3 37.2 102,360 38.5 26 44
SDRA-30-93 600 30 3 30.0 102,360 38.5 26 44
SDRA-48-43 480 48 3 58.9 163,776 38.5 30-1/4 44
SDRA-48-93 600 48 3 47.3 163,776 38.5 30-1/4 44
SDRA-60-43 480 60 3 73.3 204,720 38.5 30-1/4 44
SDRA-60-93 600 60 3 58.9 204,720 38.5 30-1/4 44
IMPORTANT: SAVE THESE INSTRUCTIONS
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 when-
ever 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, electrical 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 venti-
lation or exhaust opening as this may cause an electric
shock, fire or damage the heater.
12. To prevent a possible fire, do not block air intakes or ex-
haust 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 liq-
uids 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.

3
Set-Up and Operation
The SDRA SuperDragon is designed to be used with 20” di-
ameter 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” H2O, regardless of the fan speed selected. The outlet
temperature is controlled by a built-in thermostatic control;
the maximum outlet temperature is a function of the kW rat-
ing and the amount of air (cfm) flowing through the heater.
The addition 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”H2O. Exceeding the maximum static load will result in
the tripping of the overtemperature control. The performance
range of the SDRA units is as shown in table A.
The motor and fan have variable pitch pulleys for changing
the air flow and the ΔT. Graphs 1, 2 and 3 provide the perfor-
mance data for each size heater at the recommended mini-
mum, medium and maximum fan speeds. The curves end at
the point where the .38” H2O static load has been reached.
The temperature rise is based on using Chromalox 20” diam-
eter FX-20 flexible duct. The performance curves were deter-
mined by actual testing; therefore using flexible duct not sup-
plied 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.
Table A
kW
Fan
RPM CFM
∆T
No Load
Max. Static
Load
∆ T at Max.
Static Load
30 1800 2200 42°F .38” H2O 86°F
48 1800 2200 68°F .38” H2O 144°F
60 1800 2200 88°F .38” H2O 170°F
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 oth-
er connections are made.
6. Refer to Table B for proper size “SO” grade of cable.
7. A proper strain relief must be used with “SO” grade ca-
ble.
8. Dragon heaters are factory pre-wired for 3-phase delta
operation. Some units can be converted to single phase
operation by changing the wiring. The appropriate wiring
diagram is also located on the back of the wiring com-
partment 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.
Table B
Model kW Volts 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

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SDRA heaters can be easily field if modified to vary the fan
speed. There may be some circumstances where the use of
short lengths of duct may not create sufficient pressure drop
to achieve the desired temperature rise. This may also be the
case of using the unit without a duct. This insufficient static
pressure drop may result in high air flow, with the maximum
temperature rise below the desired level, (even after the fan
speed has been reduced to the minimum rpm). An accessory
AD-16, adjustable damper, is available and can be attached
to the heater to produce a static load, ranging from .1” to .19”
H2O which will act to reduce the amount of air flow.
The “Friction Loss” Graph below provides the actual test
data on the friction loss for the AD-16 damper attachment.
The losses are stated as the equivalent length in feet of 20”
duct.
Friction Loss AD-16 Damper
10
60
40
20
02000
1600
1400 1800 2200 2400
Fan RPM
Equivalent Duct Length FT
30
50
70
80
90
Damper Full Closed
Damper Full Open
The SDRA Dragon includes 2 thermostats. The thermostat on
the air inlet end of the unit is for the minimum air temperature
desired. The thermostat on the discharge end of the heater
is for the maximum air temperature desired. The two thermo-
stats are wired in series with the heating element contactor
coil. The temperature range of both thermostats is 60 - 180°F.
Temperature Rise vs Duct Length
30 kW
100
75
50
25
00100
75
50
25 125 150 175
Duct Length in Feet
Temperature Rise ˚F
1500
RPM
1800
RPM
2200
RPM
Temperature Rise vs Duct Length
48 kW
100
60
40
20
00100
75
50
25 125 150 175
Duct Length in Feet
Temperature Rise ˚F
120
140
160
1800
RPM
2200
RPM
1500
RPM
80
Temperature Rise vs Duct Length
60 kW
100
60
40
20
00100
75
50
25 125 150 175
Duct Length in Feet
Temperature Rise ˚F
120
140
160
1800
RPM
2200
RPM
1500
RPM
80
180
200

5
Accessories
Rear of
Heater
Front of
Heater
Adjustable
Damper
1/4-20 Wing nut
Provided with
AD-16
Duct
Adapter
Adjustable Damper and Duct Adapter
Fan Speed Adjustments
Changing the Pitch Diameter of the Sheaves:
1. Tools required: 5/32” allen wrench, 3/8” nut driver, 9/16”
box wrench and a medium size phillips screwdriver.
2. Remove the lower belt cover by removing the (5) sheet
metal screws.
3. Remove the rear grille by removing the (4) 1/4” bolts and
nuts.
4. Remove the belt cover inside the blower by removing the
(4) sheet metal screws.
5. Loosen the (4) bolts, (2) on each side. See Fig. 1.
3/8” Bolts
Figure 1
6. Loosen the (2) motor tension lock nuts and the fan belt
tension adjusting bolts. See Fig.2
3/8” Bolts
Lock Nuts
Fan belt tension
adjusting bolts
Figure 2

6
Wiring Diagrams
SDRA 30kW, 480V, 3PH
Attach all Wires on this
Side of Contactor to
Auxillary Terminals
Blk/Red
or Grey
Blk
Transformer
Control Enclosure
Blk
Wht
Run these Wires
Through 1" Conduit
Contactor
Motor Relay
Toggle Switch
L1
L2
L3
Motor
P4
P5 P6
T3
T1
T2
T9
T8
T7
T4
T6
T5
Inlet
Thermostat Outlet
Thermostat Cutout
12
1
Front of
Heater
10
Heater Terminal Box
4
7. Loosen the set screw on the fan pulley or motor pulley.
Fig. 3 shows the construction of the fan pulley, the motor
pulley is the same construction.
Fan belt tension
adjusting bolts
Figure 3
8. Rotate the front half of the pulley clockwise until it bot-
toms, then rotate counter clockwise until the set screw
aligns with the flat in the threaded half of the pulley. The
pulley is now in position for adjustment. See Table 1 for
the number of turns out. Tip: Leave allen wrench in set
screw and use free hand to fold fan blade.
Table B
Fan
RPM
No. of turns from
full closed
Fan
RPM
No. of turns from full
closed
Motor
Pulley
Fan
Pulley
Motor
Pulley
Fan
Pulley
1500 3 1-1/2 1950 1-1/2 3
1600 2-1/2 1-1/2 2000 1-1/2 3-1/2
1650 2 1-1/2 2100 1-1/2 4
1725 1-1/2 1-1/2 2200 1-1/2 4-1/2
1800 1 1-1/2 2300 1 4-1/2
1850 1/2 1-1/2
9. Retighten set screw, use of thread locking compound is
recommended.
10. Adjust fan belt tension, see Fig. 2. A 1/2” of belt deflection
is recommended. Tighten lock nuts.
11. Tighten the 3/8” bolts, see Fig. 1
12. Rotate fan blade to make sure the fan belt does not rub.
13. Reinstall top belt cover, grille and lower belt cover. Tip: In-
stalling the grille before installing the lower cover makes
it easier to access the two lower grille bolts.

7
SDRA 48kW, 480V, 3PH
SDRA 60kW, 480V, 3PH
Motor
Relay
Control Enclosure
45 Amp
Fusing
30 Amp Fusing
L1
L3
L2
Wht
Transformer
Contactor
Contactor
Blk
Toggle
Switch
Amber Pilot Light
Green Pilot Light
Run these Wire
s
Through 1/2"
Conduit
Motor
P4
P5 P6
T3
T1 T2
T9
T8
T4
T6
T5 T7
Inlet Thermostat Outlet Thermostat Cutout
1
14
1
17
18
15
13
12
Front
of
Heate
r
Heater Terminal Box
4
10
Run these Wires
through 1/4" Conduit
One end attached
to screw in terminal box
and other end attached to
screw on sub panel.
Motor
Relay
Control Enclosure
50 Amp Fusing
50 Amp Fusing
L1
L3
L2
Wht
Transformer
Contactor
Contactor
Blk
Toggle
Switch
Amber Pilot Light
Green Pilot Light
Run these Wire
s
Through 1/2"
Conduit
Motor
P4
P5
P6
Inlet Thermostat Outlet Thermostat Cutout
14
1
17
15
13
12
Heater Terminal Box
4
10
Run these Wires
through 1/4" Conduit
One end attached
to screw in terminal box
and other end attached to
screw on sub panel.
T3
T1 T2
T9
T8
T4
T6
T5
T7
11
18 22
20
2
24
23
Front
of
Heate
r

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Parts Location
Element Assembly 30kW
Element Assembly 60kW
Element Assembly 48kW
Front View with Grille Removed (All Sizes)
Side View shown with Heater and Control Terminal Box Covers Removed - All Sizes
19
12
11
11
12
12
11
VIEW SHOWING ELEMENT PLACEMENT
AND ROUTING OF THERMOSTAT CAPILLARY
AND MOUNTING OF BULB
19
12
11
12
12
12
11
11
12
12
Front of
Heater
View Showing Element Placement
and Routing of Thermostat Capillary
and Mounting of Bulb
V
IEW
S
H
O
WIN
G
ELEMENT PLA
C
EMEN
T
AND R
O
UTIN
G
O
F THERM
OS
TAT
C
APILLAR
Y
A
ND M
O
UNTIN
G
O
F BULB
19
12
11
11
11
12
12
12
11
11
11
12
12
Front of
Heater
View Showing Element Placement
and Routing of Thermostat Capillar
y
and Mounting of Bulb
Front View Shown with Grille Removed
All Sizes
(30-1/4)
Twist Wire
(20-1/2)
38 37
(44)
(38-1/2
)
16
84
36
45
80 81
20
21 18
32
21
Back of
Heater
Side View Detail Showing Pulley
and Belt Installation
Motor Pulley
Fan Pulley
77
79
78
23
Side View Shown with Heater and
Control Terminal Box Covers Removed

9
Maintenance
ELECTRIC SHOCK HAZARD. Disconnect heater from
power supply before servicing and/or inspecting
the heater; failure to do so may result in electrical
shock.
Replace or repair damaged cords or plugs immediately.
Check tightness of all electrical connections prior to energiz-
ing Dragon. Blow out or vacuum away any dirt or debris that
may have accumulated around the control enclosure fan mo-
tor or heating elements.
Renewal Parts Identification
Model No. Volts kW Ph.
Element (11)
Part No.
Element (12)
Part No.
Motor (16)
Part No.
Contactor (20)
Part No.
Transformer
(21) Part No.
Fuse Block (80)
Part No.
Fuse (81)
Part No.
Term. Block
(84) Part No.
SDRA-30-43 480 30 3 118-304793-011(3) 118-304793-013(3) 193-121843-232 072-304551-008 315-303786-001 N/A N/A N/A*
SDRA-30-93 600 30 3 118-304793-012(3) 118-304793-014(3) 193-121843-233 072-304551-008 315-304252-003 N/A N/A N/A*
SDRA-48-43 480 48 3 118-304793-011(3) 118-304793-013(6) 193-121843-232 072-304551-008(2) 315-303786-001 129-025643-001 128-026510-005(3) 303-047468-004
SDRA-48-93 600 48 3 118-304793-012(3) 118-304793-014(6) 193-121843-233 072-304551-008(2) 315-304252-003 129-025643-001 128-026510-005(3) 303-047468-004
SDRA-60-43 480 60 3 118-304793-011(6) 118-304793-013(6) 193-121843-232 072-304551-008(2) 315-303786-001 129-025643-001(2) 128-026510-006(6) 303-047468-004
SDRA-60-93 600 60 3 118-304793-012(6) 118-304793-014(6) 193-121843-233 072-304551-008(2) 315-304252-003 129-025643-001(2) 128-026510-006(6) 303-047468-004
* Wired directly to contactor.
All units contain two sets of elements. The ratings of the elements on the discharge end have a lower wattage than the elements on the inlet end of heater.
The ends of the elements are color coded, the lower wattage are color coded yellow and the higher wattage are color coded blue.
a. Lower wattage elements, discharge end, yellow coded
b. Higher wattage elements, fan end, blue coded
Item
Parts Common to all Units
Description Part No.
18 Temperature Control 300-019560-002
19 Hi-Limit Cut-out 300-049200-004
23 Toggle Switch 292-046123-001
32 Blower Assembly 021-304823-009
33 Inlet & Outlet Grille 134-304780-002(2)
36 Caster / Locking 375-122535-007
37 Handle - Right Side 139-304779-003
38 Handle - Left Side 139-304779-004
45 Semipneumatic Wheel 333-557518-006(2)
77 Pulley Var. Pitch 7/8” 225-305091-004
78 Pulley Var. Pitch 5/8” 225-305091-003
79 Pulley Belt 017-049702-009
86 Pilot Light – Green 213-122066-043
87 Pilot Light – Amber 213-122066-042
94 Thermostat Knob 169-300468-003
95 Thermostat Label 220-019122-010

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Limited Warranty:
Please refer to the Chromalox limited warranty applicable to this product at
http://www.chromalox.com/customer-service/policies/termsofsale.aspx.
© 2016 Chromalox, Inc. All rights reserved.
Chromalox
103 Gamma Drive
Pittsburgh, PA 15238
[phone]
www.chromalox.com