Nagas DF SERIES User manual

DIRECT GAS FIRED
AIR HEATER
DF SERIES
INSTALLATION
AND OPERATION MANUAL
CUSTOM GAS
SOLUTIONS,
LEGENDARY
PERFORMANCE

DF Series installation manual 2www.nagasinnovation.com
WARNING
Improper installation, modification, adjustment or maintenance may
cause damage, injury or death. Carefully read the installation, start-up
and maintenance instructions before installing or servicing this unit.
GAS ODOR
If a gas odor is detected:
1: Open all windows;
2: Do not touch any switches;
3: Extinguish all open flames;
4: Immediately notify your gas supplier.
WARNING
Using or storing fuel or any other flammable liquid or gas in open
containers near this unit is dangerous.

DF Series installation manual 3www.nagasinnovation.com
TABLE OF CONTENTS
TABLE OF CONTENTS....................................................................................................... 3
CODES REGULATING DIRECT FIRED DUCT HEATERS........................................................ 4
DF HEATERS INSTALLATION INSTRUCTIONS ................................................................... 5
1. PROFILE PLATE INSTALLATION .................................................................................. 6
2. GAS CONTROL PANEL INSTALLATION ....................................................................... 7
3. GAS PIPING CONNECTIONS ....................................................................................... 8
4. ELECTRICAL CONTROL SENSORS CONNECTIONS....................................................... 9
5. AIR PRESSURE SWITCH CONNECTION..................................................................... 10
6. IGNITION AND FLAME DETECTIONS CONNECTIONS ............................................... 10
7. START-UP INSTRUCTIONS ....................................................................................... 12
8. HEATER SHUTDOWN............................................................................................... 19
9. OPERATING SEQUENCE FOR SINGLE VOLUME DIRECT FIRED HEATER.................... 20
10. OPERATING SEQUENCE FOR DOUBLE VOLUME DIRECT FIRED HEATER............... 20
11. TROUBLESHOOTING............................................................................................. 21
START-UP REPORT......................................................................................................... 28

DF Series installation manual 4www.nagasinnovation.com
CODES REGULATING DIRECT FIRED DUCT HEATERS
Direct fired duct heaters must be installed according to local installation code for gas
equipment and any provincial or state regulations applying to this category of
equipment.
Furthermore, when suspending this unit, the following ANSI standards must be
followed: ANSI/NFPA 409 for aircraft hangars, ANSI/NFPA 88A or ANSI/NFPA 88B and
CAN/CGA B 149 in effect for public garages. Electrical installations must meet the
standards stated in the first part of the C22.1 Canadian electrical code of with the
National Electric Code ANSI/NFPA 70 in the USA, and all local applicable codes for this
category of equipment.
All electrical installations must comply with the electric diagrams of the heater. For
more information, refer to the start-up instructions, operating and adjustments
instructions and wiring diagram supplied with the unit.
WARNING
This air heater must ALWAYS:
•Be used to heat outside air (100% fresh air). No recirculation air is allowed.
•Be used to replace air exhausted from a building or through process
equipment;
•Supply air at a temperature not exceeding 72°C (160°F) or as stated in the
applicable local code.
THIS HEATER IS NOT A SPACE HEATER AND SHOULD NOT BE
USED AS SUCH. THIS HEATER MUST NOT BE USED ANYWHERE
PEOPLE MAY SLEEP.
IMPORTANT
Allow the recommended clearances upstream and downstream of the burner.
Refer to "Profile Plate Installation" section.

DF Series installation manual 5www.nagasinnovation.com
DF HEATERS INSTALLATION INSTRUCTIONS
There are 7 important steps to follow when installing the duct heater. Please read this
manual carefully and follow the instructions.
1. Profile plate installation.
2. Control panel installation.
3. Gas piping connections (main burner, pilot and vents).
4. Electrical control sensors connections.
5. Differential pressure switches connections.
6. Ignition wire and flame detection rod connections or ultra-violet detector
connections.
7. Start-up instructions.
DF HEATERS TYPICAL ASSEMBLY
Consult the manufacturer for any other assembly arrangement.
Profile plate
Burner
Gas inlet
Control panel

DF Series installation manual 6www.nagasinnovation.com
1. PROFILE PLATE INSTALLATION
Install the profile plate according to the following clearances.
WARNING
If heater is shipped assembled make a large enough opening in unit casing to
allow the insertion of the profile plate at the chosen location.
CLEARANCES TO BE RESPECTED
Table of clearances
Model F G* H**
in mm in mm in mm
DF-25, -50, -75, -100
1 25
6 152 30 762
DF-150 12 305
DF-200, -300, -375 40 1016
DF-450, -550, -700 18 457 50 1270
*: if water coils or flat filters are installed upstream this dimension has to be increased.
**: if a plenum fan is used, this dimension has to be increased by 50% or consult the manufacturer.

DF Series installation manual 7www.nagasinnovation.com
2. GAS CONTROL PANEL INSTALLATION
Locate the control panel so that the main gas pipeline (gas outlet) towards the burner is
upstream of the profiled plate which represents approximately a third of the width of
the control panel length.
TYPICAL PIPING SCHEMATIC OF AN INSTALLATION WITH THE PANEL
MOUNTED DIRECTLY ON UNIT
TYPICAL PIPING SCHEMATIC OF AN INSTALLATION WITH THE
PANEL REMOTELY MOUNTED FROM UNIT
NOTE: It is possible to install the control panel remotely from the profile plate. Standard
wires and tubes length provided with the heater is six feet (two meters). For installation
requiring a longer distance of wires and tubes, please consult the manufacturer.

DF Series installation manual 8www.nagasinnovation.com
3. GAS PIPING CONNECTIONS
(MAIN BURNER, PILOT AND VENTS)
For units installed indoors, bleed and vent
connections must be extended to the
outdoor in accordance with local codes.
Gas piping connections
Main gas piping
With a NPT
1
pipe
diameter of this size...
...Drill a hole of this size
in unit wall
Pipe length extended
outside control cabinet
¾" 1 ⅛" (29mm) 6" (152mm)
1" 1 ⅜" (35mm) 6" (152mm)
1 ½" 2" (51mm) 6" (152mm)
2" 2 ½" (64mm) 6" (152mm)
3" 3 ⅝" (92mm) 6" (152mm)
Pilot piping ½" ⅞" (22mm) 6" (152mm)
Gas connection pipe size (NPT)
1,2
Capacity
Gas inlet3
Gas inlet (2 psig)
and outlet
(½ psig) Gas outlet (2 psig)
750 MBH and less ¾" Use external gas regulator to reduce to ½ psig
From 751 to 1000 MBH 1"
From 1001 to 2500 MBH 1 ½" 1 ½" 1 ½"
From 2501 to 5000 MBH 2" 1 ½" 2"
5001 MBH and more 3" 2" 3"
Pilot, vent and bleed valve pipe size (NPT)1,2
Capacity Pilot line diameter Vent diameter Bleed valve4
750 MBH and less
(IRI option)
¼" aluminum tubing
Not required (2 x 2" Ø
openings are required
in cabinet for
ventilation)
¾"
From 751 to 1000 MBH
From 1001 to 2500 MBH
From 2501 to 5000 MBH 1"
5001 MBH and more 1 ½"
1NPT: National pipe thread
2This table is not intended for gas line sizing.
3If gas pressure exceeds ½ psi (14" w.c.), a high pressure regulator capable of modulating in a ratio of 40:1 must be added
at the unit inlet in order to adequately regulate the pressure at low fire.
4Bleed valve vent piping to the exterior must not be connected to other vents.

DF Series installation manual 9www.nagasinnovation.com
4. ELECTRICAL CONTROL SENSORS CONNECTIONS
WARNING
The sensors connections must be carried out by a qualified electrician,
respecting the unit’s electrical diagram and according to local codes.
The sequence of operation of the electrical diagram must never be modified
without consulting the manufacturer.
Electrical controls location (Installed by others)
Items Description (All wires must comply with codes, and in their absence, National Electrical Code NFPA70)
1 Low temperature limit sensor (Freeze stat, optional) (BL)
2 Modulation sensor (MT1-12/TS114) (Shielded wires required)
3 High limit air temperature control (max. 160°F)(HL)
4 Air inlet temperature sensor (TDA) (Optional)

DF Series installation manual 10 www.nagasinnovation.com
5. AIR PRESSURE SWITCH CONNECTION
Make these connections according to the following drawing. Drill two holes of ½" In. (13
mm), then use the appropriate hardware to pass the tubes through unit wall.
6. IGNITION AND FLAME DETECTIONS CONNECTIONS
SNAPPING BUSHING
IF DOUBLE WALL
RUBBER GROMMET
BLACK PLASTIC TUBE
PROFILE PLATE PROFILE PLATE
SUPPORT
PROFILE PLATE
SUPPORT
RUBBER GROMMET
PLASTIC TUBE
BLACK RING
ALUMINUM TUBE
1/8 PIPE-1/4 TUBE ADAPTOR
SNAPPING BUSHING
IF DOUBLE WALL
ALUMINUM TUBE
IN UNIT
BLACK TUBE
CLEAR TUBE IN
CONTROL BOX

DF Series installation manual 11 www.nagasinnovation.com
With flame detection rod
Components Description Wire
gauge
Color Hole diameter
to drill in wall5
1 Pilot ignition wire GTO-15 Black ½" (13mm)
2 Pilot flame detection rod GTO-15 Red ½" (13mm)
3 Burner flame detection rod ( two
required for a capacity > 2500 MBH)
GTO-15 Red with
blue stripe
½" (13mm)
4 Pilot gas tubing - -
With ultra-violet flame detector
Components Description Wire
gauge
Color Hole diameter
to drill in wall5
1 Pilot ignition wire GTO-15 Black ½" (13mm)
2 Pilot ultraviolet detector #166Supplied by
others
⅞" (22mm)
3 Burner ultra violet detector (two
required for a capacity > 2500 MBH)
⅞ (22mm)
4 Pilot - -
5Use rubber grommets where wires pass through sheet metal walls.
6Separate wires for each ultraviolet detectors
4
1
2
3
MIDCO
MAXON
2
1
3
4 1
2
3
MIDCO
MAXON
2
1
3

DF Series installation manual 12 www.nagasinnovation.com
7. START-UP INSTRUCTIONS
The following sections explain how to start-up the DF series heaters.
IMPORTANT
The following information should only be used by a qualified technician for gas
equipment installation (with qualification cards) with knowledge in electricity
and ventilation.
WARNING
Smoking is not recommended during the heater start-up.
•Voltmeter
•Ammeter
•Temperature reading device
•Tachometer (for blower RPM)
•Air pressure gauge (0" to 2" w.c. scale)
•Gas pressure gauge (-2" to 20" w.c. scale)
Recommended
tools

DF Series installation manual 13 www.nagasinnovation.com
•GAS INLET PRESSURE ADJUSTMENT
a. Ensure that the gas inlet pressure complies with the following table:
Model
Natural gas
Propane
DF 25 / 50 / 75
Min: 6" w.c. (1493 Pa)
Min: 6" w.c. (1493 Pa)
Max: 14" w.c. (3484 Pa) Max: 8" w.c. (1991 Pa)
DF 100
Min: 8" w.c. (1991 Pa) Min: 6" w.c. (1493 Pa)
Max: 14" w.c. (3484 Pa) Max: 8" w.c. (1991 Pa)
DF 150 / 200 / 300 /
375 / 450 / 550 / 700
Min: 13" w.c. (3235 Pa) Min: 11" w.c. (2734 Pa)
Max: 14" w.c. (3484 Pa) Max: 14" w.c. (3484 Pa)
For lower gas pressure consult manufacturer.
b. Ensure that the air is completely purged from the gas piping.
c. The inlet gas pressure difference from the burner operating at high fire and
the burner OFF should not exceed 1 inch of water column (249 Pa).
WARNING
WHILE THE BURNER IS IN OPERATION ENSURE THAT THERE ARE NO GAS LEAKS IN THE
ENTIRE PIPING USING A LEAK DETECTION FLUID OR A GAS DETECTOR.
DO NOT USE OPEN FLAME TO CHECK FOR LEAKS.

DF Series installation manual 14 www.nagasinnovation.com
•BURNER AIR DIFFERENTIAL PRESSURE ADJUSTMENT
NOTE: Always read the air differential pressure when air inlet filters are new and
clean.
a. For direct gas-fired burners, the airflow rate through the burner is very
important. If the air differential pressure at the burner profile plate is too high
or too low, the unit will not function properly. This could produce an excess of
carbon monoxide (CO) or trigger a FLAME FAILURE alarm.
b. To measure the differential pressure at the burner profile plate, the blower
must be in operation and discharge air temperature maintained at 70°F (21°C).
In winter, to maintain this temperature, the burner must be in operation and
the temperature selector set at 70°F (21°C).
c. Using an air pressure gauge read the differential pressure as shown in figure 1.
Figure 1

DF Series installation manual 15 www.nagasinnovation.com
d. The value of the differential pressure drop observed through the profile plate
must correspond to the value indicated in the graph below.
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
0.4 0.5 0.6 0.7 0.8
-40
-36
-32
-28
-24
-20
-16
-12
-8
-4
0
4
8
12
16
20
24
28
32
36
40
100 110 120 130 140 150 160 170 180 190 200
Outside air temperature (°F)
Static pressure drop (inches w.c.)
Outside air temperature (°C)
Static pressure drop (Pa)

DF Series installation manual 16 www.nagasinnovation.com
e. If the airflow rate measured is within specifications and, if the pressure
differential read is greater or smaller than the desired pressure drop, the
adjustment plates of the burner have to be repositioned (see figure 2).
WARNING: Shut off power supply before making any adjustment.
f. If the differential pressure reading is lower than the desired value, reduce the
opening of the profile plate by moving the adjustment plates closer to the
burner.
g. If the differential pressure reading is higher than the desired value, enlarge the
opening of the profile plate by moving the adjustment plates away of the
burner.
NOTE: For a single volume system, adjustment plates should be at an equal
distance from the burner.
h. Read the differential pressure again and repeat operations "f" and "g" as
necessary.
NOTE: The adjustment plate must not be used to adjust the final system airflow
rate. When the airflow rate requires adjustment, changing or adjusting the
blower and motor pulleys may be required.
Figure 2

DF Series installation manual 17 www.nagasinnovation.com
•PILOT ADJUSTMENT
a. The pilot is adjusted at the factory. It can also be adjusted on site by a qualified
technician following start-up instructions.
b. When adjusting the pilot gas pressure with the regulator, the main burner
should not be in operation (close the main burner gas manual valve).
c. Adjust the pilot regulator to obtain a good reading of the flame signal on the
flame safeguard control (5-10 VDC for FIREYE and 3-5 VDC for HONEYWELL).
•BURNER ADJUSTMENT: « HIGH FIRE »
a. Set the maximum capacity of the burner according to the desired maximum
temperature rise required.
Example of calculation of the maximum temperature rise:
Minimum outside temperature: -20°F (-29°C)
Desired final temperature: 70°F (21°C)
Temperature rise (ΔT): 90°F (50°C)
b. When the outside temperature does not allow for the simulation of the
specified temperature rise across the burner, adjust its maximum capacity
according to the required gas pressure indicated on the name plate of the unit.
Readjustment will be required when outside air temperature permits full fire.
c. The adjustment is made using the main burner pressure regulator (Figure 3).
For units with a capacity over 1000 MBH, use the regulator included in the
MAXITROL modulating valve (see MAXITROL service manual) (Figure 4).
NOTE: Turn the adjustment screw clockwise to increase the gas pressure to the
burner.
Turn the adjustment screw counter clockwise to reduce the gas pressure to
the burner.
With the Maxitrol series 14 device, simply disconnect terminal 4 to obtain
the maximum burner capacity.
Figure 3 Figure 4
Regulator

DF Series installation manual 18 www.nagasinnovation.com
•BURNER ADJUSTMENT: « LOW FIRE »
a. After having set the burner at high fire, disconnect terminal 8 from the
MAXITROL amplifier to set the burner at low fire.
b. Set the burner at low fire with the adjusting screw intended for this purpose
and located on the MAXITROL modulating valve (see figures 5 and 6). The
burner should then be lit over its entire length.
c. After having set the burner at low fire, the unit must be turned off and then
turned back on to ensure that it is lit over its entire length. Readjustment will
be required when outside air temperature permits full fire.
M511, M611 or ES371 MR212
•FINAL AIR TEMPERATURE ADJUSTMENT
a. Set the MAXITROL temperature selector (TD 114) to the desired final
temperature. This selector is located either in the control panel on the unit or
in the remote control station.
NOTE: When the MAXITROL temperature selector (TD 114) is installed in a
remote control station, the wires used to make the connections must be
shielded wires (with metal sheath). The length of these wires is limited to 200ft
(60m). Consult the manufacturer for longer distances.
WARNING
With an adequate leak detection fluid, ensure that there are no gas leaks in
the piping.
Make the necessary repairs if needed.
Do not let the heater operate if a gas leak is detected.
Figure 5 Figure 6
Adjusting screw
Adjusting screw

DF Series installation manual 19 www.nagasinnovation.com
8. HEATER SHUTDOWN
•EXTENDED SHUTDOWN
When the heater is shutdown for an extended period of time, it is recommended that
the gas and electric power supply be shut off.
Before turning on the heater after an extended shutdown, make sure the air is purged
from the gas pipes and that the gas pressure is adequate. An inspection is
recommended to make sure that everything is in order. Redo start-up.
•HEATER EMERGENCY SHUTDOWN
When the heater must be shut down for an emergency, the main power disconnect
should be turned OFF and gas supply be shut off by closing the manual gas supply valve
located on the gas supply line to the heater.
•TURNING ON THE HEATER AFTER A FLAME FAILURE ALARM
After a flame failure alarm, the following checks must be performed:
a. Verify the alarm code on the flame supervision relay and consult the
troubleshooting section of this manual;
b. Set the main power switch to OFF;
c. Ensure that all gas supply manual valves are open;
d. Check the blower belts; replace or adjust them if necessary;
e. Check flame safeguard relay and fire rod condition;
f. Check condition of filters and replace them if necessary;
g. Ensure that nothing obstructs the air inlet and/or outlet of the heater;
h. Ensure that nothing prevents proper operation of inlet and/or outlet air
dampers;
i. Turn ON main disconnect;
j. Press the reset button of the flame safeguard relay;
k. Ensure that the air inlet and outlet dampers are operating properly;
l. Ensure that the blower motor is operating and fan is turning;
m. Ensure that the pilot ignites properly;
n. Observe main flame lighting sequence.
If the heater still does not start, call the manufacturer or an authorized service
company for assistance.

DF Series installation manual 20 www.nagasinnovation.com
9. OPERATING SEQUENCE FOR SINGLE VOLUME DIRECT FIRED HEATER
(For guidance only)
Starting up the burner
a. Create a heating demand.
b. If outside temperature is under 70°F, the outside temperature sensor (TDA)
allows for the FIREYE flame safeguard to be energized.
c. Authorization for pilot to ignite is complete when the low and high air pressure
differential and high temperature limit switches are closed.
d. The burner starts.
e. The MAXITROL controller modulates the burner to maintain the selected set
point of the temperature selector.
10. OPERATING SEQUENCE FOR DOUBLE VOLUME DIRECT FIRED HEATER
(For guidance only)
Starting up the burner
a. Create a heating demand.
b. If outside temperature is under 70°F, the outside temperature sensor (TDA)
allows for the FIREYE flame safeguard to be energized.
c. The burner starts.
d. In low volume mode, when airflow is reduced either by the inlet damper or by
a VFD, the profile plate damper opens partially and modulates to maintain the
required air pressure drop across the burner.
e. In high volume mode, when airflow is increased either by the inlet damper or
by a VFD, the profile plate damper opens wider and modulates its position to
maintain the required air pressure drop across the burner.