Natco Fire Coil 85 User manual

InstallationandOperationInstructions Document1241
H2XXXXXXX-
HydronicBoiler
Model F85H
Volume Water Heater
Model F85V
Sizes 500–2000 MBTU/h
WARNING
If the information in this manual is not
followed exactly, a fire or explosion may
result causing property damage, personal
injury or loss of life.
Do not store or use gasoline or other
flammable vapors and liquids in the vicinity
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.
• Immediately call your gas supplier from a
nearby phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call
the fire department.
Installation and service must be performed by
a qualified installer, service agency, or gas
supplier.
AVERTISSEMENT
Assurez-vous de bien suivres les instructions
données dans cette notice pour réduire au
minimum le risque d’incendie ou d’explosion ou
pour éviter tout dommage matériel, toute
blessure ou la mort.
Ne pas entreposer ni utiliser d’essence ni
d’autres vapeurs ou liquides inflammables dans
le voisinage de cet appareil ou de tout autre
appareil.
QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:
• Ne pas tenter d’allumer d’appareils.
• Ne touchez à aucun interrupteur. Ne pas vous
servir des téléphones dansle bâtiment où
vous vous trouvez.
• Appelez immédiatement votre fournisseur de
gaz depuis un voisin. Suivez les instructions
du fournisseur.
• Si vous ne pouvez rejoindre le fournisseur de
gaz, appelez le sservice des incendies.
L’installation et l’entretien doivent être assurés par
un installateur ou un service d’entretien qualifié ou
par le fournisseur de gaz.
FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualifiedinhotwaterboilerinstallationandmaintenance.Improperinstallationand/oroperationcould
createcarbon monoxidegas influe gaseswhich couldcause seriousinjury, propertydamage, ordeath.
Improperinstallationand/or operation willvoidthewarranty. For indoorinstallations,asan additional
measure of safety, NATCO strongly recommends installation of suitable Carbon Monoxide detectors in the
vicinityof this appliance and inany adjacent occupied spaces.
InstallationandOperationInstructionsfor
Fire Coil 85

National Combustion Co., Inc.
Page 2
TABLE OF CONTENTS
SECTION 1. General Information
1.1 Introduction ........................................................ 3
1.2 ModelIdentification ............................................ 3
1.3 Warranty ............................................................ 4
1.4 Dimensions......................................................... 4
1.5 Locating theAppliance ....................................... 4
1.6 LocatingPump-Mounted WaterHeater
with Respect to Storage Tank(s)........................ 4
1.7 LocatingPump-Mounted Boiler withRespect .......
to 0Return/Supply Header .................................. 5
1.8 LocatingAppliance for Correct Horizontal Vent/ ...
DuctedAir Distance from Outside Wall .............. 5
SECTION 2. Venting and Combustion Air
2.1 CombustionAir................................................... 7
2.1.1 CombustionAirFrom Room ............................... 7
2.1.2 IntakeCombustionAir ........................................ 7
2.2 Venting ............................................................... 8
2.2.1 Vent Categories ................................................. 8
2.2.2 Category I Vent.................................................. 8
2.2.3 CommonVenting Systems ................................. 8
2.2.4 Category III Vent................................................ 9
2.3 LocatingVent & CombustionAirTerminals ......... 9
2.3.1 Side Wall Vent Terminal...................................... 9
2.3.2 SideWallCombustionAirTerminal ..................... 9
2.3.3 VerticalVentTerminal......................................... 9
2.3.4 VerticalCombustionAirTerminal ...................... 11
2.4 Common Vent Test — Boilers .......................... 11
2.5 Vent Terminals for Outdoor Units...................... 12
SECTION 3. Gas Supply and Piping
3.1 GasSupply and Piping ..................................... 12
SECTION 4A. Water Connections — Boiler
4A.1 HeatingSystem Piping:
HotSupply Connections —Boiler..................... 13
4A.2 Cold Water Make-Up — Boiler......................... 14
4A.3 Water Flow Requirements — Boiler ................. 14
4A.4 Freeze Protection — Boiler .............................. 14
SECTION 4B. Water Connections —
Water Heaters
4B.1 Water System Piping — Water Heater............. 14
4B.2 Hot Water Supply Piping — Water Heater........ 15
4B.3 Water Flow Requirements — Water Heater ..... 15
4B.4 Combined Water Heating (potable)
and Space Heating — Water Heater ................ 15
4B.5 Freeze Protection – Water Heater ................... 15
SECTION 5. Electrical Connections
5.1 Main Power...................................................... 21
5.2 Field Wiring ...................................................... 21
5.3 ExternalStagingControl Wiring........................ 26
SECTION 6. Operating Instructions
6.1 Sequence of Operation .................................... 26
6.2 Fillingthe Boiler System ................................... 26
6.3 OperatingTemperature Control........................ 27
6.4 ExternalBoiler Operations ............................... 27
6.5 LimitControls ................................................... 28
6.6 Operating the Burner and Set Up ..................... 28
6.6.1 Set Up for 0 to 2500 Feet Altitude.................... 28
6.6.2 HighAltitudeAdjustment and SetUp ................ 28
6.7 Shutting Down the Fire Coil 85 ......................... 29
6.8 To Restart the Fire Coil 85 ............................... 29
SECTION 7. Maintenance
7.1 System Maintenance........................................ 29
7.2 Appliance Maintenanceand
ComponentDescription .................................... 29
7.2.1 Burners ............................................................ 29
7.2.2 Filter................................................................. 30
7.2.3 Gas Valves....................................................... 30
7.2.4 ManualReset High LimitControl ...................... 30
7.2.5 TemperatureControl ........................................ 30
7.2.6 IgnitionControls ............................................... 30
7.2.7 Ignitors/Sensor................................................. 30
7.2.8 Transformer ..................................................... 30
7.2.9 Blowers............................................................ 30
7.2.10Flow Switch ..................................................... 30
7.2.11 HeatExchangerCoil......................................... 31
SECTION 8. Trouble Shooting
8.1 ResolvingLockouts .......................................... 31
8.2 Delayed Ignition — Possible Causes................ 31
8.3 Short Cycling — Boiler ..................................... 32
8.4 Short Cycling — Water Heater ......................... 32
8.5 HighGasConsumption..................................... 32
SECTION 9. Replacement Parts
9.1 GeneralInformation ......................................... 32
9.2 Parts List . ....................................................... 33

Fire Coil 85 (500-2000) Page 3
SECTION 1.
General Information
USING THIS MANUAL – Because Fire Coil 85
Boilers and Water Heaters are identical appliances,
with the exception of materials of manufacture,
labels and ultimate use application, this manual
provides information for the proper installation,
operation and maintenance of all products. Where
differences exist between the application of the
appliances and their operation, the sections pertinent
to only one appliance or the other will be so
identified.
In the Commonwealth of Massachusetts, this app-
liance must be installed by a licensed plumber or gas fitter.
WARNING
The Fire Coil 85 hydronic boiler or water heater must
be installed in accordance with the procedures
detailedin this manual, or theNational Combustion Co.
warranty may be voided. The installation must conform
to the requirements of the local jurisdiction having
authority, and, in the United States, to the latest
edition of the National Fuel Gas Code, ANSI Z223.1/
NFPA54. In Canada, the installation must conform to
the latest edition of the Natural Gas and Propane
Installation Code, CSA B149.1 and/or local codes.
Whererequired by the authority havingjurisdiction, the
installation of NATCO appliances must conform to the
Standard for Controls and Safety Devices for
Automatically Fired Boilers, ANSI/ASME CSD-1. Any
modifications to the unit, its gas controls, or wiring
may void the warranty. If field conditions require
modifications, consult the factory representative
beforeinitiatingsuchmodifications.
1.1 Introduction
This manual provides information necessary for the
installation, operation, and maintenance of National
Combustion Co. Fire Coil 85 copper tube appliances.
Read it carefully before installation.
All application and installation procedures should
be reviewed completely before proceeding with the
installation. Consult the National Combustion Co.
factory, or local factory representative, with any issues
or questions regarding this equipment. Experience has
shown that most operating issues are caused by
improperinstallation.
The Fire Coil 85 appliance is protected against
over pressurization. A pressure relief valve is fitted to
all appliances. It is installed on the outlet header, at the
water outlet of the appliance.
IMPORTANT: The inlet gas pressure to the appliance
must not exceed 13" W.C. (3.2kPa).
All installations must be made in accordance with:
1). In the U.S., the " National Fuel Gas
Code"ANSI Z223.1/NFPA54, Latest Edition and all
applicable local codes as required by the Authorities
Having Jurisdiction (AHJ), or
2). In Canada, the "Natural Gas and Propane
Installation Code", CSA B149.1, latest edition and
all applicable local codes as required by the AHJ.
All electrical wiring is to be done in accordance with:
1). In the U.S., the "National Electrical Code"
(NEC), ANSI/NFPA 70, latest Edition and all applicable
local codes as required by the AHJ, or
2). In Canada, the “Canadian Electrical Code - Part
1”, CSA STD. C22.1 and all applicable local codes as
required by the AHJ.
This appliance must be electrically grounded in
accordance with the applicable codes and standards
referenced above.
1.2 Model Identification
Consult the rating plate on the unit. The following
information describes the model number structure.
1-3 ModelSeries Designation
F 8 5 = Fire Coil 85
4 Usage
H = Hydronic
V = VolumeWater
5-8 Size
0 5 0 0 = 500,000 BTU/h input
0 7 5 0 = 750,000 BTU/h input
1 0 0 0 = 999,000 BTU/h input
1 2 5 0 = 1,250,000 BTU/h input
1 5 0 0 = 1,500,000 BTU/h input
1 7 5 0 = 1,750,000 BTU/h input
2 0 0 0 = 1,999,000 BTU/h input
123 4 5678 9 10 11 12 13 14 15 16
F85 A C K 1
SERIES
F 8 5 USAGE
H
V
SIZE
0500
0750
1000
1250
1500
1750
2000
FUEL
N
P
ALTITUDE
AFIRING
MODE
K2-Stage
LOCATION
CREVISION 1HEAT
EXCHANGER
B
C
K
N
P
S
OPTIONS
CODE
X
J
PUMP
OPTIONS
X
H
N
S

National Combustion Co., Inc.
Page 4
9 Fuel
N = NaturalGas
P = Propane
10 Altitude
A = 0–10,000 feet
11 Location
C = Indoor and Outdoor
12 Firing Mode
K = Two-stage
13 Revision
1 = First version of design
14 Heat Exchanger
B = Glass-lined cast iron / copper / bronze trim
(std. on water heaters)
C = Glass-lined cast iron / copper
(std. on boilers, n/a on water heaters)
K = Bronze / copper
N = Glass-lined cast iron / cupro-nickel
(n/a on water heaters)
P = Glass-lined cast iron / cu-nickel / bronze trim
S = Bronze/cupro-nickel
15 Option Code
X = Standardunit
J = CSD-1, FM, IRI, IL
16 PumpOptions
X = NoPump
H = Pump mounted F85V, hard water pump
N = Pump mounted (any), normal water pump
S = Pump mounted F85V, soft water pump
1.3 Warranty
NATCO Heating Systems’ appliances are covered
by a limited warranty. Owners should submit online
warranty registration at www.National Combustion.com.
All warranty claims must be made to an authorized
National Combustion Co. representative or directly to
Customer Service. Claims must include the serial
number and model (this information can be found on the
rating plate), installation date, and name of the installer.
Shipping costs are not included in the warranty
coverage.
Some accessory items are shipped in separate
packages. Verify receipt of all packages listed on the
packing slip. Inspect everything for damage immediately
upon delivery, and advise the carrier of any shortages or
damage. Any such claims should be filed with the
carrier. The carrier, not the shipper, is responsible for
shortages and damage to the shipment whether visible or
concealed.
1.4 Dimensions
See Figures 1 and 2.
1.5 Locating the Appliance
The appliance should be located to provide
clearances on all sides for maintenance and inspection. It
should not be located in an area where leakage of any
connections will result in damage to the area adjacent to
the appliance or to lower floors of the structure.
When such a location is not available, it is
recommended that a suitable drain pan, adequately
drained, be installed under the appliance.
The appliance is design certified by CSA-
Internationalfor installation on combustibleflooring;in
basements; in closets, utility rooms or alcoves. Fire
Coil 85 Boilers or Water Heaters must never be
installed on carpeting. The location for the appliance
should be chosen with regard to the vent pipe lengths
and external plumbing. The unit shall be installed such
that the gas ignition system components are protected
from water (dripping, spraying, rain, etc.) during
operation and service (circulator replacement, control
replacement, etc.). When vented vertically, the Fire Coil
85 must be located as close as practical to a chimney or
outside wall. If the vent terminal and/or combustion air
terminal terminate through a wall, and there is potential
for snow accumulation in the local area, both terminals
should be installed at an appropriate level above grade.
The dimensions and requirements that are shown in
Table 1 should be met when choosing the locations for
the appliance.
1.6 Locating Pump-Mounted Water Heater
with Respect to Storage Tank(s)
For best results, a pump-mounted Fire Coil 85
water heater should be located within 15 feet (4.6m) of
the storage tank(s). The pump is sized for 30 feet (9.1m)
of piping.
If the appliance must be installed with longer piping
runs, then larger diameter pipe or tubing shall be used.
Consult the factory for assistance.
1.7 Locating Pump-Mounted Boiler with
REQUIRED RECOMMENDED
APPLIANCE CLEARANCEFROM SERVICEACCESS
SURFACE COMBUSTIBLEMATERIAL CLEARANCE
inches cm inches cm
Left Side 1 2.5 24 61
Right Side 1 2.5 24 61
Top 1 2.5 12 30
Back 1 2.5 **12** 30**
Front 1 2.5 36 91
Vertical
(Category 1) 6* 15.2*
Vent
Horizontal per UL1738 venting
(Category 3) system supplier’s
Vent instructions
*1"(2.5cm)whenb-ventisused.
**Whenventand/orcombustionairconnectstotheback,recommended
clearance is 36" (91cm).
Table 1. Clearances.

Fire Coil 85 (500-2000) Page 5
Respect to Return/Supply Header
For the best results, a pump-mounted Fire Coil 85
Boiler should be located within 15 feet (4.6m) of the
supply and return headers. The pump is sized for 30 feet
(9.1m) of piping.
If the appliance must be installed with longer piping
runs, then larger diameter tubing shall be used. Consult
the factory for assistance.
1.8 Locating Appliance for Correct
Horizontal Vent/Ducted Air Distance
from Outside Wall
The forced draft combustion air blower/blowers in
Figure 1. Dimensional Data (standard units).
Air Vent Shipping Weight1
Unit Conn. Conn.
Size A B C D E W V lbs kg
500 33¾ 85 16¾ 43 6½ 17 10 25 820 615 820 425 193
750 45¾ 116 22¾ 53 6½ 17 10 25 9½ 24 615 10 25 505 229
1000 57¾ 147 28¾ 73 6½ 17 10 25 9½ 24 820 10 25 615 279
1250 68¼ 173 34 87 10¼ 26 10 25 923 820 12 30 675 306
1500 78¾ 200 39½ 100 10¼ 26 10 25 923 820 12 30 760 345
1750 89¼ 227 44¾ 113 10¼ 26 10 25 923 820 12 30 825 375
2000 99¾ 253 49¾ 127 10¼ 26 10 25 923 12 30 14 36 955 434
NOTES: 1.Add55lbs (25kg) forpump-mounted units.
Dimensions in inches cm.

National Combustion Co., Inc.
Page 6
Air Vent
Conn. Conn.
Size A B C D E F W V
500 33¾ 86 16¾ 43 6½ 17 10 25 820 46¼ 117 615 820
750 45¾ 116 22¾ 58 6½ 17 10 25 9½ 24 58¼ 148 615 10 25
1000 57¾ 147 28¾ 73 6½ 17 10 25 9½ 24 70¼ 178 820 10 25
1250 68¼ 173 34¼ 87 10¼ 26 10 25 923 80¾ 205 820 12 30
1500 78¾ 200 39½ 100 10¼ 26 10 25 923 91¼ 232 820 12 30
1750 89¼ 227 44¾ 113 10¼ 26 10 25 923 101¾ 258 820 12 30
2000 99¾ 253 49¾ 127 10¼ 26 10 25 923 112¼ 285 12 30 14 36
Figure 2. Dimensional Data (pump-mounted models).
HORIZONTAL AIRCOLLAR
UNIT VENTCOLLAR VENTPIPE &PIPE MAX.PIPE MAX.NO. SIDEWALL SIDEWALL
SIZE SIZE DIAMETER DIAMETER LENGTH OF ELBOWS VENT COMBUSTION
TERMINAL AIRTERMINAL
in cm in cm in cm ft mPARTNUMBER PARTNUMBER
500 8 20 615 615 50 15 3 CA001401 20260701
750 10 25 820 615 50 15 3 CA001401 20260701
1000 10 25 820 820 50 15 3 CA001402 20260703
1250 12 30 820 820 50 15 3 CA001403 20260703
1500 12 30 820 820 50 15 3 CA001403 20260703
1750 12 30 820 820 50 15 3 CA001403 20260703
2000 14 36 12 30 12 30 50 15 3 CA001404 20260706
Table 2. Horizontal Vent / Combustion Air Parameters.

Fire Coil 85 (500-2000) Page 7
the appliance has/have sufficient power to pull air and
vent properly when the following guidelines for
horizontal air and vent are followed (see Table 2).
NOTE: The vent collar size is larger than the size of the
vent pipe that can be used. Vent collar size and
horizontal pipe diameters can be found in Table 2. The
larger vent collar size is to accommodate Category I
(vertical) vent systems.
NOTE: When located on the same wall, the Fire Coil 85
combustionairintaketerminalmustbeinstalledaminimum
of 12" (30cm) below the exhaust vent terminal and sep-
aratedby aminimum of36 inches (91cm)horizontally.
The air intake terminal must be installed high enough
to avoid blockage from snow, leaves and other debris.
SECTION 2.
Venting and Combustion Air
2.1 Combustion Air
Fire Coil 85 boilers and water heaters must have
provisions for combustion and ventilation air in
accordance with section 5.3, Air for Combustion and
Ventilation, of the National Fuel Gas Code, ANSI
Z223.1, or Sections 7.2, 7.3 or 7.4 of CSA B149.1,
Installation Codes, or applicable provisions of the local
building codes.
A Fire Coil 85 appliance may receive combustion
air from the space in which it is installed, or it can be
ducted directly to the unit from the outside. Ventilation
air must be provided in either case.
2.1.1 CombustionAirFromRoom
In the United States, the most common
requirements specify that the space shall communicate
with the outdoors in accordance with method 1 or 2,
which follow. Where ducts are used, they shall be of the
same cross-sectional area as the free area of the
openings to which they connect.
Method 1: Two permanent openings, one
commencing within 12 inches (30 cm) of the top and one
commencing within 12 inches (30 cm) of the bottom, of
the enclosure shall be provided. The openings shall
communicate directly, or by ducts, with the outdoors or
spaces that freely communicate with the outdoors. When
directly communicating with the outdoors, or when
communicating to the outdoors through vertical ducts,
each opening shall have a minimum free area of 1 square
inch per 4000 BTU/hr (5.5 square cm/kW) of total input
rating of all equipment in the enclosure. When
communicating to the outdoors through horizontal ducts,
each opening shall have a minimum free area of not less
than 1 square inch per 2000 BTU/hr (11 square cm/kW)
of total input rating of all equipment in the enclosure.
Table 3 shows data for this sizing method, for each Fire
Coil 85 model.
Method2:Onepermanentopening,commencing
within 12 inches (30 cm) of the top of the enclosure, shall
be permitted. The opening shall directly communicate
with the outdoors or shall communicate through a vertical
or horizontal duct to the outdoors or spaces that directly
communicate with the outdoors and shall have a
minimum free area of 1 square inch per 3000 BTU/hr (7
square cm/kW) of the total input rating of all equipment
located in the enclosure. This opening must not be less
than the sum of the areas of all vent connectors in the
confined space.
Other methods of introducing combustion and
ventilation air are acceptable, providing they conform to
the requirements in the applicable codes listed above.
In Canada, consult local building and safety codes or,
in absence of such requirements, follow CSA B149.1.
2.1.2 IntakeCombustionAir
The combustion air can be taken through the wall,
or through the roof. When taken from the wall, it must be
taken from out-of-doors by means of the NATCO
horizontal wall terminal (see Table 2). When taken from
the roof, a field-supplied rain cap or an elbow
arrangement must be used to prevent entry of rain water
(see Figure 3).
Use single-wall galvanized pipe, per Table 4, for
the combustion air intake (see Table 2 for appropriate
size). Route the intake to the heater as directly as
possible. Seal all joints with tape. Provide adequate
hangers. The unit must not support the weight of the
combustion air intake pipe. Maximum linear pipe length
allowed is 50 feet (15.2m). Three elbows have been
calculated into the 50-foot (15.2m) linear run. Subtract
10 allowable linear feet (3.0m) for every additional
elbow used (see Table 2). When fewer than 3 elbows are
used, the maximum linear pipe length allowed is still 50
feet (15.2m).
The connection for the intake air pipe is on the
filter box. The Fire Coil 85 appliances have venting and
combustion air ducting attached to the top.
UNIT EACHOPENING*
SIZE SQUAREINCHES SQUARECM
500 125 807
750 188 1213
1000 250 1613
1250 313 2020
1500 375 2420
1750 438 2826
2000 500 3226
*NetFree Area in SquareInches/ Square cm
Areaindicated isfor one of two openings;one atfloor level and one
attheceiling, so the totalnetfreearea could be doublethefigures
indicated.
Thischartisforusewhencommunicatingdirectlywiththeoutdoors.
Forspecial conditions andalternatemethods,refertothe latest
editionof ANSIZ223.1.
Note: Checkwithlouvermanufacturersfornetfreeareaoflouvers.
Correct for screen resistance to the net free area if a screen is
installed.Checkalllocal codes applicable to combustionair.
Table 3. Combustion Air Openings.

National Combustion Co., Inc.
Page 8
In addition to air needed for combustion, air shall
also be supplied for ventilation, including all air required
for comfort and proper working conditions for personnel.
The Fire Coil 85 loses less than 1 percent of its input
rating to the room, but other heat sources may be present.
2.2 Venting
2.2.1 VentCategories
Depending upon desired Fire Coil 85 venting, it
may be considered a Category I or a Category III
appliance. In general, a vertical vent system will be a
Category I system. However, in rare instances, a vertical
vent system may be considered Category III. In the U.S.,
the National Fuel Gas Code (ANSI Z223.1-Latest
Edition), or in Canada the CSA B149.1 (latest edition),
defines a Category I vent system, and includes rules and
tables to size these vent systems. If the Fire Coil 85’s
vertical vent system does not satisfy the criteria for
Category I venting, it must be vented as a Category III
system.
All Fire Coil 85 vent systems which discharge
horizontally (without the use of a power venter) are
considered Category III vent systems.
2.2.2 CategoryIVent
When vented as a category I appliance, the vent
system must conform to the National Fuel Gas Code (ANSI
Z223.1-Latest Edition) in the U.S., or in Canada, to CSA
B149.1 (latest edition). The vent system must be sized and
installed for a Category I Fan-Assisted Appliance.
If chimney height is greater than 25 feet, or if multiple
units are vented into the same vertical vent, a barometric
damper must be installed on each appliance, such that the
flue draft does not exceed (negative) 0.1" w.c.
If using a power venter for any type of Category I
venting, the draft should be set between (negative) 0.01
and 0.10" w.c.
2.2.3 CommonVentingSystems
Fire Coil 85 units are Category I fan-assisted when
vented vertically and adhering to all applicable codes.
When common venting Fire Coil 85 fan-assisted
unit with other appliances through one shared vertical
duct called a “common vent”, special care must be taken
by the installer to ensure safe operation. In the event that
the common vent is blocked, it is possible, especially for
fan-assisted devices, to vent backwards through non-
operating appliances sharing the vent, allowing
combustion products to infiltrate occupied spaces. If the
appliances are allowed to operate in this condition,
serious injury or death may occur.
WARNING
Operation of appliances with a blocked common vent
may lead to serious injury or death. If safe operation of
allappliances connected to acommon vent cannot be
assured,including preventionofspillage offlue gasses
intolivingspaces,commonventingshouldnotbeapplied,
andappliances shouldeach bevented separately.
Proper vent sizing, construction and safety
requirements from the National Fuel Gas Code, ANSI
Z223.1 or in Canada, from CSA B149.1 as well as all
applicable local codes must be followed.
As an additional precaution, it is recommended that
a Carbon Monoxide (CO) alarm be installed in all
enclosed spaces containing combustion appliances.
Fire Coil 85 units are not allowed to be vented into
a common horizontal vent system, unless a properly
sized vent fan is used, and the common vent system is
properly designed by the vent fan manufacturer or a
qualifiedengineer.
Refer to the installation and operating instructions on
all appliances to be common vented for instructions,
warnings, restrictions and safety requirements. If safe
operation of all appliances connected to a common vent
cannot be assured, including prevention of spillage of flue
gasses into living spaces, common venting should not be
applied, and appliances should each be vented separately.
2.2.4 CategoryIIIVent
When the Fire Coil 85 is vented with horizontal
discharge, it must be installed per this installation
manual and the venting system manufacturer’s
installation instructions. The vent system must be sealed
stainless steel (see Table 5).
Figure 3. Combustion Air and Vent Through Roof.
TERM DESCRIPTION
Pipe Single-wall galvanized steel pipe, 24 gauge
minimum (either insulated or non-insulated)
Joint Permanent duct tape or aluminum tape
Sealing
Table 4. Required Combustion Air Piping Material.

Fire Coil 85 (500-2000) Page 9
Route the vent pipe to the heater as directly as
possible. Seal all joints and provide adequate hangers as
required in the venting system manufacturer’s Instal-
lation Instructions. Horizontal portions of the venting
system must be supported to prevent sagging and may
not have any low sections that could trap condensate.
The unit must not support the weight of the vent pipe.
Horizontal runs must slope downwards not less than ¼
inch per foot (2 cm/m) from the unit to the vent terminal.
Reference Table 1 for the size of the Category III vent
system. Up to three elbows can be used with 50 linear
feet (15.2m) of pipe. Subtract 10 allowable linear feet
(3.0m) for every additional elbow used.
WARNING
The outdoor vent terminal gets hot. Unit must be
installed in such a way as to reduce the risk of burns
from contact with the vent terminal.
2.3 Locating Vent & Combustion Air
Terminals
2.3.1 SideWallVentTerminal
The appropriate NATCO side wall vent hood must
be used, and is listed in the installation and operation
manual. The terminal provides a means of installing the
vent piping through the building wall, and must be
located in accordance with ANSI Z223.1/NFPA 54 and
applicable local codes. In Canada, the installation must
be in accordance with CSA B149.1 or .2 and local
applicable codes. Consider the following when installing
theterminal:
1. Figure 4 shows the requirements for mechanical
vent terminal clearances for the U.S. and Canada.
2. Vent terminals for condensing appliances or
appliances with condensing vents are not permitted
to terminate above a public walkway, or over an
area where condensate or vapor could create a
nuisance or hazard.
3. Locate the vent terminal so that vent gases cannot
be drawn into air conditioning system inlets.
4. Locate the vent terminal so that vent gases cannot
enterthe buildingthrough doors, windows, gravity
inlets or other openings. When possible, locations
under windows or near doors should be avoided.
5. Locate the vent terminal so that it cannot be
blocked by snow. The National Fuel gas code
requires that it be at a minimum of 12" above
grade. In a location that has the possibility of snow
accumulation, it is critical the installer places the
vent at least 12" higher than the maximum potential
snow line. Seek local municipalities and their
codes for appropriate installation techniques.
6. Locate the terminal so the vent exhaust does not settle
on building surfaces or other nearby objects. Vent
products may damage such surfaces or objects.
7. If the boiler or water heater uses ducted
combustion air from an intake terminal located on
the same wall, locate the vent terminal at least 3
feet (0.9m) horizontally from the combustion air
terminal, and locate the vent terminal at least 1 foot
(0.3m) above the combustion air terminal.
2.3.2 SideWallCombustionAirTerminal
The NATCO side wall combustion air terminal
(see Table 2) must be used when the unit takes its
combustion air through a duct from a side wall. Consider
thefollowingwheninstallingtheterminal:
1. Do not locate the air inlet terminal near a source of
corrosive chemical fumes (e.g., cleaning fluid,
chlorinated compounds, etc.)
2. Locate the terminal so that it will not be subject to
damage by accident or vandalism.
3. Locate the combustion air terminal so that it cannot
be blocked by snow. The National Fuel gas code
requires that it be at a minimum of 12" above
grade. Depending on local conditions, the installer
should ensure that it remains at least 12" above the
maximum potential snow line. Seek local
municipalities and their codes for appropriate
installation techniques.
WARNING: It is critical that the combustion air
intake and the vent terminals remain at least 12"
above the maximum potential snow line. If either
the vent terminal or the air terminal is blocked by
snow, there may be potential for the unit to
produce excess carbon monoxide and or
recirculateflue gasses intothe building/dwelling.
Personal injury or DEATH may occur. Natural
snowfall, drifting, and banking should all be taken
into account when locating the terminals in a
potentialsnowenvironment.
4. If the Fire Coil 85 is side-wall vented to the same
wall, locate the vent terminal at least 3 feet (0.9m)
horizontallyfromthecombustionairterminal, and
locate the vent terminal at least 1 foot (0.3m) above
the combustion air terminal (see Figure 4).
2.3.3 VerticalVentTerminal
When the unit is vented through the roof, the vent
must extend at least 3 feet (0.9m) above the point at
which it penetrates the roof. It must extend at least 2 feet
(0.6m) higher than any portion of a building within a
horizontal distance of 10 feet (3.0m), and high enough
above the roof line to prevent blockage from snow.
When the combustion air is taken from the roof, the
combustion air must terminate at least 12" (30cm) below
TERM DESCRIPTION
Pipe Must comply with UL Standard 1738
such as Type 29-4C Stainless Steel
(either insulated or non-insulated).
Joint Follow vent manufacturer’s instructions
Sealing
Table 5. Required Horizontal Venting Material.

National Combustion Co., Inc.
Page 10
U.S. Installations (see note 1) Canadian Installations (see note 2)
A= Clearance above grade,veranda, porch, 12 inches (30 cm) 12 inches (30 cm)
deck,or balcony
B= Clearance towindow or door thatmay be 4 feet (1.2 m) below or to side of opening; 36 inches (91cm)
opened 1 foot (30 cm) above opening
C= Clearanceto permanentlyclosedwindow See note 4 See note 5
D= Vertical clearance toventilated soffit located
abovetheterminalwithin a horizontal See note 4 See note 5
distanceof 2 feet(61cm) from thecenter
lineofthe terminal
E= Clearancetounventilated soffit See note 4 See note 5
F= Clearance tooutside corner See note 4 See note 5
G= Clearance toinside corner See note 4 See note 5
H= Clearance to each side of center line 3 feet (91 cm) within a height 15 feet above
extendedabovemeter/regulator assembly See note 4 themeter/regulator assembly
I= Clearancetoservice regulator vent outlet See note 4 3 feet (91 cm)
J= Clearancetononmechanical air supplyinlet
to buildingor the combustion airinlet to 4 feet (1.2 m) below or to side of opening; 36 inches (91cm)
anyotherappliance 1 foot (30 cm) above opening
K= Clearance toa mechanical air supplyinlet 3 feet (91 cm) above if within 10 feet (3 m) 6 feet (1.83 m)
horizontally Vent termination notallowed in this location
Vent termination notallowed in this location forcategory IV appliances. Avent shall not
L= Clearanceabove paved sidewalk or paved forcategoryIV appliances. For CategoryIII terminate directly abovea sidewalk or paved
drivewaylocated on public property appliances,vent must terminate atleast 7 driveway that islocated between twosingle
feet(2.13m) above thesidewalk or driveway. familydwellingsand serves both dwellings.
ForCategoryIII appliances thatdonot violate
thepreviouscondition,vent must terminate
at least 7 feet (2.13m) above the sidewalk or
driveway.
M= Clearanceunderveranda, porch, deck, See note 4 12 inches (30 cm) (see note 3)
orbalcony
Notes:
1. Inaccordance withthe currentANSI Z223.1 / NFPA54NationalFuel Gas Code.
2. Inaccordance withthecurrent CSA-B149.1 Installation Codes.
3. Permittedonly ifveranda,porch, deck, orbalcony is fullyopenon a minimumof two sides beneaththe floor.
4. Forclearances notspecified inANSI Z223.1 /NFPA54, clearanceis in accordancewith local installationcodes and therequirements of
thegas supplier.
5. For clearances not specified in CSA-B149.1, clearance is in accordance with local installation codes and the requirements of the gas supplier.
Figure 4. Combustion Air and Vent Through Side Wall.

Fire Coil 85 (500-2000) Page 11
the vent terminal (see Figure 3). Seek local
municipalities and their codes for appropriate
installation techniques.
FromMassachusettsRules andRegulations248 CMR5.08:
(a) For all side wall horizontally vented gas fueled equipment
installed in every dwelling, building or structure used in
whole or inpart for residential purposes, including those
owned or operated by the Commonwealth and where the
side wall exhaust vent termination is less than seven (7)
feet above finished grade in the area of the venting,
including but not limited to decks and porches, the
followingrequirements shall besatisfied:
1. INSTALLATIONOFCARBONMONOXIDEDETECTORS.
Atthe timeof installationof theside wallhorizontal ventedgas
fueledequipment, theinstallingplumber orgasfitter shall
observethat ahard-wired carbonmonoxide detectorwith an
alarmand batteryback-up isinstalled onthe floor levelwhere
thegas equipmentis tobe installed.In addition, theinstalling
plumberor gasfittershall observethat abattery operatedor
hard-wiredcarbon monoxidedetector withan alarmis installed
oneach additionallevel ofthe dwelling,building orstructure
servedby thesidewall horizontalvented gasfueledequipment.
Itshall be theresponsibility of theproperty owner tosecure the
servicesof qualifiedlicensed professionalsfor theinstallation
ofhard-wired carbonmonoxide detectors.
a.In theevent thatthe sidewall horizontallyventedgas fueled
equipmentis installed ina crawl space oran attic, thehard-
wiredcarbon monoxidedetector withalarm andbattery back-
upmay beinstalled onthe nextadjacentfloor level.
b.In theevent thatthe requirements ofthis subdivisioncannot
bemet atthe timeof completionof installation,the ownershall
havea period ofthirty (30) days tocomply with theabove
requirements;provided, however,that during saidthirty (30)
dayperiod, abattery operated carbonmonoxide detectorwith
analarmshall beinstalled.
2. APPROVEDCARBONMONOXIDEDETECTORS.Each
carbonmonoxide detector asrequired inaccordance with the
aboveprovisions shallcomplywith NFPA720andbeANSI/UL
2034listed and IAScertified.
3. SIGNAGE.Ametalor plasticidentification plateshall be
permanentlymounted tothe exteriorof thebuilding ata
minimumheight of eight(8) feet abovegrade directly inline
withtheexhaust ventterminal forthehorizontally ventedgas
fueledheating applianceor equipment.The sign shallread, in
printsize no less thanone-half (½) inchin size, "GAS VENT
DIRECTLYBELOW.KEEPCLEAROFALLOBSTRUCTIONS".
4. INSPECTION.The stateor local gasinspector ofthe sidewall
horizontallyventedgas fueledequipmentshall notapprovethe
installationunless, uponinspection,the inspectorobserves
carbonmonoxide detectorsand signageinstalled in accor-
dancewith the provisionsof 248 CMR5.08(2)(a) 1 through4.
(b) EXEMPTIONS: The followingequipment is exemptfrom
248 CMR 5.08(2)(a) 1 through 4:
1. Theequipmentlisted inChapter 10entitled"Equipment Not
RequiredTo BeVented"inthe most currentedition of NFPA54
asadopted by theBoard; and
2. ProductApprovedsidewall horizontalventedgas fueled
equipmentinstalled ina roomor structure separatefrom the
dwelling,building or structureused in whole orin part for
residentialpurposes.
(c) MANUFACTURER REQUIREMENTS- GAS EQUIPMENT
VENTING SYSTEM PROVIDED. Whenthe manufacturerof
ProductApprovedsidewall horizontallyvented gasequipment
providesa ventingsystem designorventing systemcompo-
nentswith theequipment, theinstructions providedby the
manufacturerfor installationof theequipment andtheventing
systemshallinclude:
1. Detailedinstructions forthe installationof theventingsystem
designor theventing systemcomponents;and
2. Acomplete partslist forthe ventingsystem designor venting
system.
(d) MANUFACTURER REQUIREMENTS- GAS EQUIPMENT
VENTING SYSTEMNOT PROVIDED. Whenthe manufacturer
ofa ProductApprovedsidewall horizontallyvented gasfueled
equipmentdoes notprovide theparts forventing thefuel gases,
butidentifies "specialventing systems",the followingrequire-
mentsshall besatisfied bythe manufacturer:
1. Theidentification ofeach "specialventing system"shall include
eitherthe listingof the website,phone numberor
manufacturer'saddresswhere theventing systeminstallation
instructionscan beobtained; and
2. The"special ventingsystems" shallbe ProductApprovedbythe
Board,and theinstructions providedwith thatsystemshall
includea partslist anddetailed installationinstructions.
(e) A copy of all installation instructions for the Product
Approved side wall horizontally vented gas fueled
equipment, and all the venting instructions, parts lists,
and/or design instructions for the venting system shall
remain with the appliance or equipment at the completion
of the installation.
Manufacturers'websiteswhere ventingsysteminstallation
instructionsmay beobtainedis locatedon theNATCO website
at:http://www.NationalCombustion.com.
2.3.4 VerticalCombustionAirTerminal
When combustion air is taken from the roof, a
field-supplied rain cap or an elbow arrangement must be
used to prevent entry of rain water (see Figure 3). The
opening on the end of the terminal must be at least 12"
(30cm) above the point at which it penetrates the roof,
and high enough above the roof line to prevent blockage
from snow. When the vent terminates on the roof, the
combustion air must terminate at least 12" (30cm) below
the vent terminal.
2.4 Common Vent Test — Boilers
When an existing boiler is removed from a common
venting system, the common venting system is likely to
be too large for proper venting of the appliances
remaining connected to it.
At the time of removal of an existing boiler, the
following steps shall be followed with each appliance
remainingconnected to thecommon venting systemplaced
inoperation, while the other appliancesremaining con-
nected to the common venting system are not in operation.
1. Seal any unused openings in the common venting
system.
2. Visually inspect the venting system for proper size
and horizontal pitch and determine there is no
blockage or restriction, leakage, corrosion and other
deficiencies which could cause an unsafe condition.
3. Insofar as it is practical, close all building doors
and windows and all doors between the space in
which the appliances remaining connected to the
common venting system are located and other
spaces of the building. Turn on clothes dryers and
any appliance not connected to the common venting
system. Turn on any exhaust fans, such as range
hoods and bathroom exhausts, so they will operate
at maximum speed. Do not operate a summer
exhaust fan. Close fireplace dampers.

National Combustion Co., Inc.
Page 12
SIZE DISTANCEFROMGASMETER
AND OR LAST STAGE REGULATOR
GAS TYPE 0-100' 100-200' 200-300'
500 natural 1½" 2" 2"
500 propane 1" 1½" 1½"
750 natural 2" 2" 2½"
750 propane 1½" 1½" 2"
1000 natural 2" 2½" 3"
1000 propane 1½" 2" 2½"
1250 natural 2½" 2½" 3"
1250 propane 2" 2" 2½"
1500 natural 2½" 3" 3"
1500 propane 2" 2½" 2½"
1750 natural 2½" 3" 3"
1750 propane 2" 2½" 2½"
2000 natural 3" 3" 3½"
2000 propane 2½" 2½" 3"
Metric Equivalent
SIZE DISTANCEFROMGASMETER
AND OR LAST STAGE REGULATOR
GAS TYPE 0-31m 31-61m 61-91m
500 natural 3.8cm 5.1cm 5.1cm
500 propane 2.5cm 3.8cm 3.8cm
750 natural 5.1cm 5.1cm 6.4cm
750 propane 3.8cm 3.8cm 5.1cm
1000 natural 5.1cm 6.4cm 7.6cm
1000 propane 3.8cm 5.1cm 6.4cm
1250 natural 6.4cm 6.4cm 7.6cm
1250 propane 5.1cm 5.1cm 6.4cm
1500 natural 6.4cm 7.6cm 7.6cm
1500 propane 5.1cm 6.4cm 6.4cm
1750 natural 6.4cm 7.6cm 7.6cm
1750 propane 5.1cm 6.4cm 6.4cm
2000 natural 7.6cm 7.6cm 8.9cm
2000 propane 6.4cm 6.4cm 7.6cm
NOTES: 1. Thesefiguresarebased on 1/2" (0.12kPa)watercolumn
pressuredrop.
2. Checksupplypressureandlocalcoderequirements
beforeproceedingwithwork.
3. Pipefittings must beconsidered when determininggas
pipesizing.
Table 7. Gas Piping Sizes.
4. Place in operation the appliance being inspected.
Follow the lighting instructions. Adjust thermostat
so appliance will operate continuously.
5. Test for spillage at the draft hood relief opening
after 5 minutes of main burner operation. Use the
flame of a match or candle, or smoke from a
cigarette, cigar or pipe.
6. After it has been determined that each appliance
remainingconnected to thecommon venting system
properly vents when tested as outlined above,
return doors, windows, exhaust fans, fireplace
dampers and any other gas burning appliance to
their previous conditions of use.
7. Any improper operation of the common venting
system should be corrected so that the installation
conforms to the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 and/or CSA B149.1, Installation
Codes. When resizing any portion of the common
venting system, the common venting system should
be resized to approach the minimum size as
determined using the appropriate tables in Part II of
the National Fuel Gas Code, ANSI Z223.1/NFPA
54 and/or CSA B149.1, Installation Codes.
2.5 Vent Terminals for Outdoor Units
For outdoor applications, the vent and combustion
air openings must be covered with proper terminals to
prevent rain, snow and other objects from falling into the
Fire Coil 85.
If local codes allow, outdoor installations may use
1' of appropriately sized galvanized single wall or B-
Vent and a rain cap for exhaust vent termination in the
default configuration (venting out of the top). Note that
some local codes may require a higher vertical vent
height,extending aboveany perimeterfencing, etc.In
installations where the appearance of the vent is
objectionable, the low profile vent terminals in Table 6
may be used.
Combustion air inlets consist of appropriately sized
galvanized pipe and elbows to allow the open end to
face down aside the boiler. This is available as a
Commercial Kit from the manufacturer.
Part numbers for the low profile terminals to cover the
vent and combustion air openings are shown in Table 6.
SECTION 3.
Gas Supply and Piping
3.1 Gas Supply and Piping
Gas piping should be supported by suitable
hangers or floor stands, not by the appliance.
Fire Coil 85’s gas train allows the user to pipe the
gas from either the right side or the left side of the unit.
As shipped, the right side of the gas train is capped off,
and there is a manual valve on the left side. If desired,
the manual valve on the left side of the gas train may be
moved to the right side, and the cap on the right side
may be moved to the left.
Review the following instructions before
OUTDOORVENT OUTDOOR
UNITSIZE TERMINAL COMBUSTION
AIRTERMINAL
500 20254703 D2007900
750 20254705 D2007900
1000 20254705 D2008000
1250 D2007700 D2008000
1500 D2007700 D2008000
1750 D2007800 D2008000
2000 D2007800 D2008200
Table 6. Vent Terminals for Outdoor Units.

Fire Coil 85 (500-2000) Page 13
proceedingwith theinstallation.
1. Verify that the appliance is fitted for the proper
type of gas by checking the rating plate. Fire Coil
85 appliances are equipped to operate at elevations
up to 10,000 feet (3050m). Fire Coil 85 appliances
may be adjusted to operate properly at altitudes
above 2500 feet (see Section 6.6.2) and the input
will be reduced if the heating value of the gas
supply is below sea level values.
2. The maximum inlet gas pressure must not exceed
13" W.C (3.2kPa). The minimum inlet gas pressure
is 5" W.C. (1.2kPa).
3. Refer to Table 7, size supply.
4. Run gas supply line in accordance with all
applicable codes.
5. Locate and install manual shutoff valves in
accordance with state and local requirements.
6. A sediment trap must be provided upstream of the
gas controls.
7. All threaded joints should be coated with piping
compound resistant to action of liquefied
petroleum gas.
8. The appliance and its individual shutoff valve must
be disconnected from the gas supply piping during
any pressure testing of that system at test pressures
in excess of 1/2 PSIG (3.45kpa).
9. The unit must be isolated from the gas supply
system by closing its individual manual shutoff
valve during any pressure testing of the gas supply
piping system at test pressures equal to or less than
1/2 PSIG (3.45kpa).
10. The appliance and its gas connection must be leak
tested before placing it in operation.
11. Purge all air from gas lines.
WARNING
Do not use open flame to check for leaks. An open
flame could lead to explosion, which could result in
property damage, serious injury or death.
NOTE: The Fire Coil 85 appliance and all other gas
appliances sharing the gas supply line must be firing at
maximum capacity to properly measure the inlet supply
pressure. The pressure can be measured at the supply
pressure port on the gas valve. Low gas pressure could
be an indication of an undersized gas meter, undersized
gas supply lines and/or an obstructed gas supply line.
SECTION 4A.
Water Connections — Boiler
4A.1 Heating System Piping:
Hot Supply Connections — Boiler
NOTE: This appliance must be installed in a closed
pressure system with a minimum of 12 psi (82.7kPa)
static pressure at the boiler.
Hot water piping should be supported by suitable
hangers or floor stands. Do not support piping with this
appliance. Due to expansion and contraction of copper
pipe, consideration should be given to the type of
hangers used. Rigid hangers may transmit noise through
the system resulting from the piping sliding in the
hangers. It is recommended that padding be used when
rigid hangers are installed. Maintain 1" clearance to
UNIT 20°F 25°F 30°F 35°F
SIZE flow H/L flow H/L flow H/L flow H/L
gpm feet gpm feet gpm feet gpm feet
500 43 1.7 34 1.1 28 0.9 24 0.7
750 64 3.3 51 2.3 43 1.7 36 1.2
1000 85 5.0 68 3.6 57 3.1 49 2.2
1250 106 8.1 85 6.1 71 4.7 61 3.4
1500 128 10.0 102 7.2 85 5.5 73 4.2
1750 N/R N/R 119 10.5 99 8.4 85 5.8
2000 N/R N/R 136 12.5 113 10.4 97 8.3
Metric Equivalent
UNIT 11°C 14°C 17°C 19°C
SIZE flow H/L flow H/L flow H/L flow H/L
lpm m lpm m lpm m lpm m
500 161 0.5 129 0.3 107 0.3 92 0.2
750 241 1.0 193 0.7 161 0.5 138 0.4
1000 321 1.5 257 1.1 214 0.9 184 0.7
1250 401 2.5 322 1.9 269 1.4 231 1.0
1500 483 3.0 386 2.2 322 1.7 276 1.3
1750 N/R N/R 451 3.2 375 2.6 322 1.8
2000 N/R N/R 515 3.8 429 3.2 368 2.5
Notes: gpm= gallons per minute,lpm= liters perminute,
H/L=headloss, ft = headlossinfeet, m = headlossinmeters.
Maximumtemperaturerise is 35°F(19°C),as shown. Headloss is
forboiler’sheatexchangeronly.N/R=notrecommended.
Table 8. Water Flow Requirements — F85H.Figure 5. Typical Gas Train Configuration.

National Combustion Co., Inc.
Page 14
combustibles for hot water pipes.
Pipe the discharge of the relief valve (full size) to a
drain or in a manner to prevent injury in the event of
pressure relief. Install an air purger, an air vent, a
diaphragm-type expansion tank, and a hydronic flow
check in the system supply loop. Minimum fill pressure
must be 12psig (82.7kPa). Install shutoff valves where
required by code.
Suggested piping diagrams are shown (see Figures
6 through 14). These diagrams are meant only as a
guide. Components required by local codes must be
properly installed.
4A.2 Cold Water Make-Up — Boiler
1. Connect the cold water supply to the inlet
connection of an automatic fill valve.
2. Install a suitable back flow preventer between the
automatic fill valve and the cold water supply.
3. Install shut off valves where required.
NOTE: The boiler, when used in connection with a
refrigeration system, must be installed so the chilled
medium is piped in parallel with the boiler with
appropriate valves to prevent the chilled medium from
entering the boiler.
The boiler piping system of a hot water heating
boiler connected to heating coils located in air handling
appliances where they may be exposed to refrigerated
air circulation must be equipped with flow control
valves or other automatic means to prevent gravity
circulation of the boiler water during the cooling cycle.
A boiler installed above radiation level, or as
required by the authority having jurisdiction, must be
provided with a low water cutoff device either as a part
of the boiler or at the time of boiler installation.
4A.3 Water Flow Requirements — Boiler
A hydronic heating (closed loop) application re-
circulates the same fluid in the piping system. As a
result, no new minerals or oxygen is introduced into the
system. To ensure a proper operating temperature
leading to long boiler life, a flow rate has been
established based on the fluid temperature rise for this
specific size boiler.
Pump-mounted boilers can be ordered for use in
primary secondary piping systems. The pumps used are
sized for the headloss through the heater, plus 30 feet
(9.1m) of full-sized piping (same size as boiler outlet)
and a normal number of fittings.
Table 8 specifies water flow rates for boilers,
which will enable the user to size a pump. The headloss
shown is for the heater only, and the user will need to
add the headloss of the system piping to properly size
the pump.
The minimum inlet water temperature for the Fire
Coil 85 is 120°F (49°C) to avoid condensing on the
copper coils.
4A.4 Freeze Protection — Boiler
Boiler installations are not recommended in areas
where the danger of freezing exists unless proper
precautions are made for freeze protection. A non toxic,
heating system, anti-freeze may be added to the hydronic
system provided that the concentration does not exceed
50% and the anti freeze contains an anti foamant. When
a 50/50 mixture is used, increase the water flow
requirements by 15%, and increase the headloss
requirements by 20%.
Power outage, interruption of gas supply, failure of
system components, activation of safety devices, etc., may
prevent a boiler from firing. Any time a boiler is subjected
to freezing conditions, and the boiler is not able to fire, and/
or the water is not able to circulate, there is a risk of
freezing in the boiler or in the pipes in the system. When
water freezes, it expands. This can result in bursting of
pipes in the system, or damage to the boiler, which could
result in leaking or flooding conditions.
IMPORTANT NOTES: Different glycol products may
provide varying degrees of protection. Glycol products
must be maintained properly in a heating system, or they
may become ineffective. Consult the glycol specifications,
or the glycol manufacturer, for information about specific
products, maintenance of solutions, and set up according
to your particular conditions.
SECTION 4B.
Water Connections —
Water Heaters
4B.1 Water System Piping —
Water Heater
Hot water piping should be supported by suitable
hangers or floor stands. Do not support piping with this
appliance. Due to expansion and contraction of copper
pipe, consideration should be given to the type of
hangers used. Rigid hangers may transmit noise through
the system resulting from the piping sliding in the
hangers. It is recommended that padding be used when
rigid hangers are installed.
The Fire Coil 85 can be used with several different
types of readily available storage tanks. A pump draws
water from the storage tank and pumps the water through
the heater and back into the tank. Pump-mounted units have
a circulating pump built into the water heater. The pumps
used are sized for the headloss through the heater, plus 30
feet (9.1m) of full-sized piping (same size as boiler outlet)
and a normal number of fittings. Pumps used on pump-
mounted unit are sized for soft/normal or hard water, so
make sure a pump-mounted unit matches the water quality
of the installation.
Pipe the outlet from the heater’s relief valve such
that any discharge from the relief valve will be
conducted to a suitable place for disposal when relief
occurs. Do not reduce line size or install any valves in

Fire Coil 85 (500-2000) Page 15
this line. The line must be installed to allow complete
drainage of both the valve and the line.
Suggested piping diagrams are shown in Figures 10
through 13. These diagrams are meant only as a guide.
Components required by local codes must be properly
installed.
The minimum inlet water temperature for the Fire
Coil 85 is 120°F (49°C) to avoid condensing on the
copper coils.
4B.2 Hot Water Supply Piping —
Water Heater
Follow the tank manufacturer’s guidelines for
completion of the hot water system connections.
NOTE: A listed temperature and pressure relief valve
listed as complying with the Standard for Relief
Valves and Automatic Gas Shutoff Devices for Hot
Water Supply Systems (ANSI Z21.22 / CSA 4.4) of
suitable discharge capacity must be installed in the
separate storage tank system.
If the Fire Coil 85 water heater is installed in a
closed water supply system, such as one having a
backflow preventer in the cold water supply line, the
relief valve may discharge periodically, due to thermal
expansion. Means (such as a properly-sized expansion
tank) shall be provided to control thermal expansion.
Contact the water supplier or local plumbing inspector
on how to control this situation.
4B.3 Water Flow Requirements —
Water Heater
In a water heating application (an open system),
new water is constantly being introduced. With the new
water comes a fresh supply of minerals that can be
deposited on the unit’s heat exchanger. This is
commonly known as scaling. The amount of minerals
will depend upon the hardness of the water. Water can
also be aggressive, and can erode metals, including
copper, if the water is moved too quickly. The water
flow requirements for the Fire Coil 85 water heater are
based upon the hardness of the water. The water flow is
kept high enough to prevent scaling, but low enough to
prevent tube erosion. For extremely soft or hard water,
cupro-nickel tubes are available. Contact a NATCO
Representative if you have questions or concerns about
water quality.
Pump-mounted water heaters can be ordered with
standard pumps for soft or normal water or with pumps
for hard water. The pumps used are sized for the
headloss through the heater, plus 30 feet (9.1m) of full-
sized piping (same size as heater outlet) and a normal
numberoffittings.
Table 9 specifies water flow rates for water
heaters, which will enable the user to size a pump. The
headloss shown is for the heater only, and the user will
need to add the headloss of the piping system to
properly size the pump.
4B.4 Combined Water Heating (potable)
and Space Heating — Water Heater
NOTE: These systems are not allowed in the
CommonwealthofMassachusetts.
Piping and components connected to this water
heater for the space heating application shall be suitable
for use with potable water.
Toxic chemicals, such as used for boiler treatment,
shall not be introduced into the potable water used for
space heating.
This water heater when used to supply potable
water shall not be connected to any heating system or
component(s) previously used with a non-potable water
heatingappliance.
When the system requires water for heating at
temperatures higher than required for other uses, an
anti-scald mixing or tempering valve shall be
installed to temper the water for those uses in order
to reduce scald hazard potential.
4B.5 Freeze Protection – Water Heater
Although Fire Coil 85 water heaters are design-
certified for outdoor installations, such installations are
not recommended in areas subject to freezing
temperatures, unless proper precautions are taken.
Power outage, interruption of gas supply, failure of
system components, activation of safety devices, etc., may
prevent a heater from firing. Any time a heater is sub-
jected to freezing conditions, and the heater is not able
to fire, and/or the water is not able to circulate, there is
a risk of freezing in the heater or in the pipes in the
system. When water freezes, it expands. This can result in
bursting of pipes in the system, or damage to the heater,
which could result in leaking or flooding conditions.
Contact the local factory representative or NATCO
foradditionalinformation.
SECTION 5.
Electrical Connections
WARNING
Theappliance must be electrically grounded in
accordance with the requirements of the authority
havingjurisdiction or, in the absence ofsuch
requirements, with the latest edition of the National
Electrical Code, ANSI/NFPA 70, in the U.S. and with
latest edition of CSA C22.1 Canadian Electrical Code,
Part 1, in Canada. Do not rely on the gas or water
piping to ground the metal parts of the boiler. Plastic
pipe or dielectric unions may isolate the boiler
electrically.Serviceandmaintenancepersonnel,who
work on or around the boiler, may be standing on wet
floors and could be electrocuted by an ungrounded
boiler.

National Combustion Co., Inc.
Page 16
Figure 6. Hydronic Piping — Multiple Boilers, Primary Secondary System.
Figure 7. Hydronic Piping — Multiple Boilers, Low Temperature System.

Fire Coil 85 (500-2000) Page 17
Figure 8. Hydronic Piping — One Boiler, Multi-Temperature System.
Figure 9. Hydronic Piping - Primary-Secondary, Reverse-Return.

National Combustion Co., Inc.
Page 18
Figure 10. Hydronic Piping - Primary-Secondary, Reverse-Return, Low Temperature.
Figure 11. Water Heater Piping — One Heater, One Tank.

Fire Coil 85 (500-2000) Page 19
Figure 12. Water Heater Piping — Multiple Heaters, One Tank.
Figure 13. Water Heater Piping — One Heater, Multiple Tanks.

National Combustion Co., Inc.
Page 20
Figure 14. Water Heater Piping — Multiple Heaters, Multiple Tanks.
Table 9. Water Flow Requirements — F85V.
Unit gpm ft Temp Rise °F lpm m Temp Rise °C
Size S N H S N H S N H SNH SNH SNH
500 45 68 90 1.8 2.3 3.5 19 13 9 170 257 341 0.5 0.7 1.1 10 7 5
750 45 68 90 2.1 3.0 6.0 28 19 14 170 257 341 0.6 0.9 1.8 16 10 8
1000 45 68 90 2.3 3.6 6.1 38 25 19 170 257 341 0.6 1.1 1.9 21 14 10
1250 68 68 90 3.8 3.8 6.3 31 31 24 257 257 341 1.2 1.2 1.9 17 17 13
1500 68 68 90 3.9 3.9 6.5 38 38 28 257 257 341 1.2 1.2 2.0 21 21 16
1750 68 68 90 4.0 4.0 6.7 44 44 33 257 257 341 1.2 1.2 2.0 24 24 18
2000 112 112 112 10.0 10.0 10.0 30 30 30 424 424 424 3.0 3.0 3.0 17 17 17
NOTES: S= softwater (1 to 7.5 grainshardness).
N= normal water(7.6 to 17grainshardness).
H= hard water (morethan 17 grainshardness).
gpm= gallons perminute; lpm =liters per minute;ft = headlossin feet; m= headloss inmeters.
Headlossisfor heater's heatexchangeronly.