Daikin FC Series Instruction Manual

Installation and Maintenance IM 684-6
Group: Applied Air Systems
Part Number: IM 684
Date: October 2018
Daikin Rooftop Systems
Forced Draft Gas Fired Furnace
FC ****A* with RM7897A Flame Safeguard

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Introduction.......................................3
Hazardous Information Messages ....................3
General .........................................4
Warranty Exclusion ................................4
Ventilation & Flue Pipe Requirements .................4
Factory Mounting .................................4
Factory Checkout .................................4
Installation........................................5
General .........................................5
Flue Box ........................................5
Wind Deector ...................................5
Electrical ........................................6
Gas Pressure Requirements.........................6
Gas Piping ......................................6
Valve and Regulator Venting.........................7
Normally Open Vent Valve ..........................7
Gas Piping Routing into Unit.........................7
On-The-Roof Piping (Models 020-140) ...............7
Through-the-Curb Piping
(Models 020-140) ...............................7
Typical Piping Connections ........................8
Gas Piping
(Models 150 through 200)...........................8
Gas Piping within the Vestibule.......................8
Field Gas Piping Required ..........................8
Condensate Drain.................................9
Vestibule (Models 150 through 200) ...................9
Start-Up and Operating Procedures .................10
Start-Up Responsibility ............................10
Start-Up Procedure...............................10
Before Start-Up ................................10
Start-Up Preliminary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Low Fire Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Pilot Start-Up....................................11
Main Flame Start-Up..............................11
Typical Electrical Schematic for MicroTech®III Control
System
with RM7897A .................................12
Typical Sequence of Operation (3-1 gas burner)
for MicroTech III Control Systems....................13
Modulating Gas Burner without End Switch Cycling ....14
Typical Sequence of Operation (3-1 gas burner)
with no MicroTech III Control System . . . . . . . . . . . . . . . . . 15
Service..........................................16
General ........................................16
Pilot Air & Gas Adjustments ........................16
Pressure Regulator...............................16
Pilot Orice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Ignition Electrode Adjustments . . . . . . . . . . . . . . . . . . . . . . 16
Flame Rod Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Pilot Location Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Air Pickup Tube Adjustment ........................17
Gun Assemblies .................................17
Modulating Linkage Adjustment .....................18
Altitude Considerations............................18
Combustion Testing ..............................18
Verify Input Rate .................................18
Check CO2, CO & Stack Temperature ................19
Cleaning Heat Exchangers .........................19
Leakage Symptoms ..............................20
Checking For Leaks ..............................20
Causes of Failures ...............................20
Replacing a Heat Exchanger .......................21
Furnace Condensation ............................21
Rear Inspection Cover ............................21
Combination Fan and Limit Control ..................22
Replacing “White Rogers” Fan Limit Controller with
“Antunes” ......................................22
Maintenance .....................................23
Monthly ......................................23
Twice Yearly ..................................23
Yearly .......................................23
Flame Safeguard ................................23
Keyboard Display Module..........................23
Operation ......................................24
Normal Start-Up .................................24
LED Display ....................................24
Troubleshooting ..................................25
Fault Codes......................................30
Typical Parts List .................................34
Controls, Settings and Functions....................35
Capacities and Dimensions.........................36
Performance and Service History....................37
IM 684-6 • ROOFTOP SYSTEMS 2 www.DaikinApplied.com
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Hazardous Information Messages
WARNING
FIRE OR EXPLOSION HAZARD!
Failure to follow safety warnings exactly could result in serious injury, death,
or property damage.
Be sure to read and understand the installation, operation, and service in
this manual.
Improper installation, adjustment, alteration, service, or maintenance can
cause serious injury, death, or property damage.
— Do not store or use gasoline or other ammable vapors and liquids in the
vacinity of this or any other appliance.
— WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your
building.
• Leave the building immediately.
• Immediately call your gas supplier from a phone remote from the
building. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the re department.
— Installation and service must be performed by a qualied installer,
service agency, or the gas supplier.
AVERTISSEMENT
RISQUE D´INCENDIE OU D´EXPLOSION!
Le non respect des mises en garde pourrait entraîner des blessures graves,
la mort, ou des pertes matérielles.
Prende soin de lire et de comprendre les instructions d´installation, de
fonctionnement, et d´entretien contenues dans ce guide.
Une installation, un réglage, une modication, une réparation, ou un
entretien inapproprié peut entraîner des blessures graves, la mort, ou des
pertes matérielles.
— Ne pas entreposer ni utiliser d´essence ou autre vapeurs ou liquides
inammables à proximeté de cet appareil ou de tout autre appareil.
— QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ
• Ne tentez pas d´allumer un appareil.
• Ne touchez pas à un interrupteur; n´utilisez pas de téléphone dans
l´édice où vous vous trovez.
• Sortez de l´édice immédiatement.
• Appelez immédiatement le fournisseur de gaz à partir d´un téléphone
a l´extérieur de l´édice. Suivez les instructions du fournisseur de
gaz.
• Si vous ne pouvez joindre le fournisseur de gaz, appelez les pompiers.
— L´installation et les réparations doivent être conées, à un installateur
qualié, ou au fournisseur de gaz.
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www.DaikinApplied.com 3 IM 684-6 • ROOFTOP SYSTEMS

When writing to Daikin for service or replacement parts, refer
to the model number of the unit as stamped on the serial plate,
attached to the unit. If there is an in-warranty failure, state the
date of installation of the unit and the date of failure along with
an explanation of the malfunctions and the description of the
replacement parts required. Parts are warranted for ninety (90)
days unless covered by original unit warranty.
General
WARNING
Units equipped with gas heating must not be operated in an atmosphere
contaminated with chemicals which will corrode the unit such as halogenated
hydrocarbons, chlorine, cleaning solvents, refrigerants, swimming pool
exhaust, etc. Exposure to these compounds may cause severe damage to
the gas furnace and result in improper or dangerous operation. Operation
of the gas furnace in such a contaminated atmosphere constitutes product
abuse and will void all warranty coverage by the manufacturer. Questions
regarding specic contaminants should be referred to your local gas utility.
This forced draft gas burner is specically designed for use
with the furnace on Daikin rooftop heating and air conditioning
units which are for outdoor installation only. Each model size
has unique burner head components to tailor the shape of the
ame to each particular stainless steel combustion chamber,
to match the capacity requirement, and to o󰀨er a desirable
turndown potential when arranged for modulation. This is a
forced draft burner with a high pressure combustion air fan and
will operate against pressure. This eliminates the need for draft
inducers, chimneys, draft hoods, barometric dampers, and
Breidert caps.
Warranty Exclusion
Warranty is void if the furnace is operated in the presence of
chlorinated vapors, if the airow through the furnace is not in
accordance with rating plate, or if the wiring or controls have
been modied or tampered with.
Ventilation & Flue Pipe
Requirements
The Daikin rooftop unit is equipped with an outdoor air louver
to supply adequate combustion air. The unit also has a ue
outlet assembly and requires no additional chimney, ue pipe,
Breidert cap, draft inducer, etc.
Factory Mounting
This burner and gas train have been installed and wired at
the factory. See Gas Piping Routing into Unit, page 7.
Also note that Models 150 through 200 have the burner
removed for shipment; see Vestibule — Model 150–200,
page 9.
Factory Checkout
This complete heating plant was red and tested at the
factory. It was adjusted to the required capacity and e󰀩ciency.
Modulating air and gas linkages, pressure regulators, and
stops were adjusted for proper operation at all ring levels. The
unit was red through several complete sequences of start-
up through shuto󰀨 to check operation. A check was made of
the air switch, gas pressure switch, high limit operation, and
combustion characteristics including CO2and CO (at several
ring rates on modulating burners).
If the burner was specied for operation at higher altitudes,
combustion air adjustments were compensated to result in
proper settings at the higher altitude. This checkout normally
eliminates on-the-job start-up problems; however, the
equipment is subject to variable job conditions and shipping
shocks can change adjustments, cause damage, and loosen
connections and fasteners. Therefore, it is necessary to go
through the complete start-up procedure even though the unit
may appear to be operating properly.
IM 684-6 • ROOFTOP SYSTEMS 4 www.DaikinApplied.com
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General
The installation of this equipment must be in accordance
with the regulations of authorities having jurisdiction and all
applicable codes. It is the responsibility of the installer to
determine and follow the applicable codes. Sheet metal parts,
self-tapping screws, clips, and such items inherently have
sharp edges, and it is necessary that the installer exercise
caution. This equipment must be installed by an experienced
professional installation company that employs fully trained and
experienced technicians.
Table 1: Flue Height by Unit Model
Burner
Model
Number
Furnace Size
(Output MBH)
Unit Sizes
015D–042D 045D–075D 080D–105D
020 200
6.00 Inches
7.50 Inches —
025 250 —
032 320
8.50 Inches
—
040 400 —
050 500
6.0 Inches
064 640
065 650
079 790
080 800
100 1000
110 1100 — —
140 1400 — —
150 1500 — —
200 2000 — —
Flue Box
The ue box (see Figure 1)is not installed at the factory
because it would increase the width of the unit beyond the
allowable shipping width. All holes are pre punched, the
fasteners are furnished and everything is shipped inside a box
in the burner section. On Models 150 through 200, it is shipped
in the same crate as the vestibule. Remove and discard the
shipping cover installed over the furnace tube outlets before
installing the ue box.
1. Remove the screws (2) in the casing of the unit that line
up with the bottom lip holes of the ue box tube sheet
(3). These screws will later be replaced, at which time
they will also attach the bottom of the ue box to the unit.
2. Install ue box wrapper sheet (4) by sliding it up from
below. Attach with side screws (5). At this time reinstall
bottom screws (2).
Figure 1: Flue Box
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The wind deector is not installed at the factory because it
would increase the width of the unit beyond the allowable
shipping width. The deector is shipped in a box in the burner
section. Install the wind deector over the combustion air
intake opening of the burner compartment before operating the
burner. Use inner hinge screws on top hinged door (see Figure
2). Side hinged doors have holes for mounting (see Figure 6).
Models 020 and 025 have a di󰀨erent style wind deector. It
mounts on the door and has a top opening ush with the roof
of the unit (see Figure 17 on page 19).
Figure 2: Wind Deector, Models (032 thru 140)
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Electrical
WARNING
Improper installation, adjustment, alteration, service or maintenance
can cause property damage, severe personal injury or death. Read the
installation, operating and maintenance instructions thoroughly before
installing or servicing this equipment.
If you smell gas:
1. Open Windows and ventilate area thoroughly.
2. Don’t touch electrical switches.
3. Eliminate open ames, pilot lights, arcing or sparking
equipment, or other sources of ignition.
4. Evacuate the area.
5. Immediately call your gas supplier from a different area.
Do not use and store gasoline or other ammable vapors or liquids in open
containers near this appliance or in areas sharing ventilation with it..
The Daikin burner receives its electrical power from the main
unit control panel. No additional power wiring must be routed
to the burner. The sequencing of the burner is also controlled
through this panel and therefore is factory wired. No additional
wiring will be required. Note that Models 150 through 200
furnaces require reassembly of some electrical connections as
the burner is removed for shipment.
Gas Pressure Requirements
The pressure furnished to the appliance gas pressure regulator
immediately before the main gas valve must not exceed 13.9
in. W.C. or be below the minimum specied in Table 10 on
page 36, Column 14. When the supply pressure is above
13.9 in. W.C., a high pressure regulator must precede the
appliance gas pressure regulator. The inlet gas pressure
must not exceed the maximum pressure rating of the high
pressure regulator, and the outlet pressure must furnish gas
to the appliance pressure regulator within the pressure range
mentioned above.
Gas Piping
The connection size at the burner is shown in Table 10 under
columns 17 and 18. Gas piping must be sized to provide the
minimum required pressure at the burner when the burner is
operating at maximum input. Consult your local utility on any
questions on gas pressure available, allowing piping pressure
drops, and local piping requirements.
Install all piping in accordance with the National Fuel Gas Code
(ANSI Z223.1), (NFPA 54-1999) and any applicable local codes.
The proper size piping must be run from the meter to the
gas burner without reductions. Undersized piping will result
in inadequate pressure at the burner. The pressure will be at
its lowest when it is needed the most, at times of maximum
demand. Therefore, it can cause intermittent hard-to-nd
problems because the problem may have left before the
service technician has arrived. Avoid the use of bushings
wherever possible.
Table 2: Capacity of Pipe Natural Gas (CFH)
WITH PRESSURE DROP OF 0.3" W.C. & SPECIFIC GRAVITY OF 0.60
PIPE
LENGTH
(FT.)
PIPE SIZE-INCHES (IPS)
½ ¾ 1 1¼ 1½ 2 2½ 3 4
10 132 278 520 1050 1600 2050 4800 8500 17500
20 92 190 350 730 1100 2100 3300 5900 12000
30 73 152 285 590 890 1650 2700 4700 9700
40 63 130 245 500 760 1450 2300 4100 8300
50 56 115 215 440 670 1270 2000 3600 7400
60 50 105 195 400 610 1150 1850 3250 6800
70 46 96 180 370 560 1050 1700 3000 6200
80 53 90 170 350 530 990 1600 2800 5800
90 40 84 160 320 490 930 1500 2600 5400
100 38 79 150 305 460 870 1400 2500 5100
125 34 72 130 275 410 780 1250 2200 4500
150 31 64 120 250 380 710 1130 2000 4100
175 28 59 110 225 350 650 1050 1850 3800
200 26 55 100 210 320 610 980 1700 3500
NOTE: Use multipliers in Tables 2 and 3 for other gravities and pressure drops.
IM 684-6 • ROOFTOP SYSTEMS 6 www.DaikinApplied.com
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Table 3: Specic Gravity other than 0.60
SPECIFIC GRAVITY MULTIPLIER
0.50 1.100
0.60 1.000
0.70 0.936
0.80 0.867
0.90 0.816
1.00 0.775
PROPANE-AIR
1.10 0.740
PROPANE
1.55 0.622
BUTANE
2.00 0.547
Table 4: Pressure Drop other than 0.3”
PRESSURE
DROP MULTIPLIER PRESSURE MULTIPLIER
0.1 0.577 1.0 1.83
0.2 0.815 2.0 2.58
0.3 1.000 3.0 3.16
0.4 1.16 4.0 3.65
0.6 1.42 6.0 4.47
0.8 1.64 8.0 5.15
Remove all burrs and obstructions from pipe. Do not bend
pipe; use elbows or other pipe ttings to properly locate pipe.
A drip leg must be installed in the vertical line before each
burner such that it will not freeze. Install unions so gas train
components can be removed for service. All pipe threads must
have a pipe dope which is resistant to the action of LP gas.
After installation, pressurize the piping as required and test all
joints for tightness with a rich soap solution. Any bubbling is
considered a leak and must be eliminated. Do not use a match
or ame to locate leaks.
Valve and Regulator Venting
Valve diaphragm vents, pressure regulator vents, and pressure
switch vents are located in the outdoor burner vestibule and
therefore vent tubing is not run to the outside of this vestibule.
If local regulations require that this be done, it is a part of the
eld gas piping hookup. Remove any plastic protector plugs
from regulator and valve vents.
Normally Open Vent Valve
Vent valves such as required by IRI for over 1000 MBh input
units must always be routed to the outdoors. This is eld
piping.
Gas Piping Routing into Unit
On-The-Roof Piping (Models 020-140)
1. Remove knockout (1) at corner of burner vestibule door
and saw out corner of door. See Figure 3. Make saw cuts
(2) tangent to round hole and square with door edges.
2. Install pipe corner plate (3) on vestibule, locating on pre-
punched holes. See Figure 4. This part is shipped inside
the vestibule with ue box.
3. Route gas supply pipe through hole. Carefully plan pipe
route and tting locations to avoid interference with
swinging of doors, etc.
Through-the-Curb Piping
(Models 020-140)
1. Remove bottom access panel (5). See Figure 4.
2. Remove knockout (4) and make an opening (6) through
bottom deck directly below knockout hole.
3. Route gas pipeline through these openings and seal
them o󰀨 with suitable grommets (7). Figure 3 Section
A-A.
4. Replace bottom access panel (5).
Figure 3: Pipe Routing and Knockout
Figure 4: Pipe Corner Plate
2
1
A
A
2
7
7
4
6
Gas Supply
Section A-A
See Figure 4
3
45
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Typical Piping Connections
Figure 5: Connections
A = Shuto󰀨 Cock (ball valve)
B = Union - Furnished.
C = Gas Pipe - Routed in through front
D = Gas Pipe - Routed in through curb
E = Factory Piped Gas Trains
F = Pilot Gas Tubing
Gas Piping
(Models 150 through 200)
The gas piping cannot be routed up to the burner from within
the curb on Models 150 through 200. Gas piping must be
routed across the roof to under the burner vestibule, or a pitch
pocket can be provided there. The installer must cut a hole in
the bottom panel of the overhanging burner vestibule through
which to route the gas line up to the burner gas train. The
bottom panel of the vestibule is at approximately the same
elevation as the top of the curb.
Gas Piping within the Vestibule
The gas piping layout within the vestibule will vary according
to the complexity and size of the gas train relative to the
available room within the vestibule. As an example, a gas
train with a high pressure regulator and an extra safety
shuto󰀨 valve (when required for IRI, etc.) will require careful
use of the available space. The examples shown in Figure 5
indicate typical piping layouts.
Field Gas Piping Required
The gas train components have all been factory installed and
require only a connection to the supply gas line. The manual
shuto󰀨 valve is located within the burner vestibule. If local
codes require a manual shuto󰀨 valve that is accessible from
outside the unit, that valve must be relocated or an additional
valve added. In locating such a valve, it is to be readily
accessible and located such that no obstructions interfere with
operation of the handle.
The furnace and manual furnace shuto󰀨 valve must be
disconnected from the gas supply piping system during any
pressure testing of that system at test pressure in excess of
½ psi (3.5 kPa).
The furnace must be isolated from the gas supply piping
system by closing the manual furnace shuto󰀨 valve during
any pressure testing of the gas supply piping system at test
pressures equal to or less than of ½ psi (3.5 kPa).
D
C
W
ith Shuto Cock
In Front
D
C
A
With Shuto Cock
Folded back
AB
E
F
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Condensate Drain
All units are equipped with a 3/4" I.P. stainless steel
condensate drain pipe projecting from the back side of the
furnace section (see Figure 16 and Figure 17) and the ue
box corners (see Figure 1). Drainage of condensate directly
onto the roof may be acceptable in certain areas, refer to local
codes. If applicable codes or regulations require, this can be
routed to a drain. A trap is not recommended and heat tape or
some other method of freeze protection is required.
Vestibule (Models 150 through 200)
WARNING
For installations where the ambient temperatures fall below freezing, if the
condensate is not piped to the drain properly, or does not include some
heat protection, the condensate will freeze. Frozen drain lines may cause a
build up of condensate inside the heat exchanger resulting in leakage and
damage to the rooftop unit and probably to the facility.
These two furnace sizes exceed the allowable shipping width
and for this reason the burner is disconnected and removed
for shipment. A sheet metal vestibule weather enclosure is
also disassembled for shipment. At installation the burner
must be re-mounted, the tagged electrical connections re-
attached, and the vestibule re-assembled and mounted as
shown in Figure 6. These items are packed in a crate and
shipped as a separate item.
Figure 6: Vestibule — Model 020–140
Figure 7: Vestibule — Model 150–200
Cut Gas Line Opening
Hinge
Side Panel
Door
Top Panel
Side Panel,
With Latch
Bottom Panel
#10 Screw
Door
Fasten Wind Deflector
To Door With #10 Screws,
(Door & Wind Deflector
Part of Vestibule Kit)
Step 1 Step 2 Step 3
Step 4 Step 5
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Start-Up Responsibility
The start-up organization is responsible for determining that
the furnace, as installed and as applied, will operate within the
limits specied on the furnace rating plate.
1. The furnace must not exceed the specied Maximum
MBh Input. See Verify Input Rate on page 18.
2. The furnace must not operate at an airow below the
specied Minimum Airow CFM. On variable air volume
systems it must be determined that the furnace will not
be operated if or when system cfm is reduced below the
specied minimum airow cfm.
3. It must be established that the gas supply is within the
proper pressure range. See Gas Pressure Requirements
on page 6.
Start-Up Procedure
WARNING
Overheating or failure of the gas supply to shut off can cause equipment
damage, severe personal injury or death. Turn off the manual gas valve to
the appliance before shutting off the electrical supply..
Start-up and service of this equipment must be done by
trained, experienced technicians. It is highly recommended
that the initial start-up and future service be performed by
Daikin trained technicians who are familiar with working on
live equipment. A representative of the owner or the operator
of the equipment should be present during start-up to receive
instructions in the operation, care and adjustment of the unit.
Before Start-Up
1. Notify inspectors or representatives who may be required
to be present during start-up of gas fuel equipment.
These could include the gas utility company, city gas
inspectors, heating inspectors, etc.
2. Review the equipment and service literature and become
familiar with the location and purpose of the burner
controls. Determine where the gas and power can be
turned o󰀨 at the unit, and before the unit.
3. Determine that power is connected to the unit and
available.
4. Determine that the gas piping, meter, and service
regulator have been installed, tested, and meet the
equipment requirements.
5. Determine that proper instruments will be available for
the start-up. A proper start-up requires the following:
voltmeter, manometer or gauges with ranges for both
manifold pressure and inlet gas pressure, keyboard
display module or a 20K ohm/volt meter for ame
safeguard, signal strength measurement, CO2indicator,
carbon monoxide indicator, and a stopwatch for timing
the gas meter.
Start-Up Preliminary
Close main and pilot gas cocks. Install a keyboard display
module or connect a 20K ohm/volt meter to the test jack on the
ame safeguard. See Figure 7.
1. Check the burner fan wheel for binding, rubbing, or loose
setscrews. Inspect the air damper and gas valve linkages
for binding and check the linkage fasteners for tightness.
2. Check power. Position control switch on burner panel to
AUTO. The POWER LED on the ame safeguard should
come on and, after 10 seconds, the burner motor should
start. Check for Counter-clockwise rotation as viewed
through blower housing inlet. If motor does not start,
press the reset button on the ame safeguard. If motor
still does not start, consult the appropriate section of the
Troubleshooting Chart, page 26. Continue on to Item 3
when burner motor will run when the switch is positioned
to AUTO.
3. Check voltage. With the switch at AUTO, measure the
voltage across ame safeguard terminals 5 and L2. If it
is not between 108 and 132 volts, check the voltage and
tapping connections to the supplying transformer at the
unit’s main control panel.
4. Purge the gas lines. Close the main gas valves and turn
the electrical switches o󰀨. Make sure there are no arcing
or sparking switches, motors, or other equipment, pilot
lights, open ames, or other sources of ignition in the
areas sharing ventilation. Disconnect the pilot gas tube at
the pilot pressure regulator and bleed the gas line of all
air. Close the pilot cock and reconnect the pilot tubing.
5. Leak check. Using a rich soap-water mixture and a
brush, check the gas lines for leaks. Correct all leaks
before starting burner.
IM 684-6 • ROOFTOP SYSTEMS 10 www.DaikinApplied.com
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