State Industries SBD85500PE User Manual

Instruction Manual
COMMERCIAL GAS WATER HEATERS
MODELS SBD85500NE &
SBD85500PE
SERIES 120/121
500 Tennessee Waltz Pkwy
Ashland City, TN 37015
INSTALLATION - OPERATION - SERVICE
- MAINTENANCE - LIMITED WARRANTY
ASME CRN
WARNING: If the information in these instructions is not followed exactly, a fire or explosion may result causing property damage, personal injury or death.
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 neighbor’s phone. Follow the gas supplier’s instructions.
Low Lead Content
If you cannot reach your gas supplier,
call the fire department.
Installation and service must be performed by a qualified installer, service agency or the gas supplier.
Thank you for buying this energy efcient water heater. We appreciate your condence in our products.
PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.
PRINTED 0211 318298-001
Failure to follow these instructions and safety messages could result in death or serious injury.
This manual must remain with the water heater.
TABLE OF CONTENTS
SAFE INSTALLATION, USE AND SERVICE........................................ 3
APPROVALS ........................................................................................ 3
GENERAL SAFETY INFORMATION .................................................... 4
Precautions ...................................................................................... 5
Grounding Instructions ....................................................................5
Hydrogen Gas Flammable ............................................................... 5
INTRODUCTION ..................................................................................6
Abbreviations Used .........................................................................6
Qualications ...................................................................................6
FEATURES AND COMPONENTS .......................................................7
The Hydro Cannon (self-cleaning system) ......................................7
High Limit Switch ............................................................................. 7
Electronic Ignition Control ................................................................ 7
Exhaust Inducer (blower assy.)........................................................7
Uncrating .........................................................................................7
INSTALLATION CONSIDERATIONS ...................................................8
Rough In Dimensions ......................................................................8
Recovery Capacities ........................................................................ 8
Gas and Electrical Characteristics ................................................... 8
Locating the Water Heater ............................................................... 9
Clearances ......................................................................................9
Installation On Combustible Flooring ............................................. 10
Insulation Blanket ..........................................................................10
Hard Water ....................................................................................10
Circulation Pumps .........................................................................10
High Altitude Installations .............................................................. 11
Propane Installations ..................................................................... 11
Natural Gas Installations ............................................................... 11
INSTALLATION REQUIREMENTS ....................................................12
Gas Pressure Requirements .........................................................12
Supply Gas Regulator ...................................................................12
Power Supply ................................................................................12
Water Temperature Control and Mixing Valves.............................. 12
Dishwashing Machines .................................................................. 13
Closed Water Systems .................................................................. 13
Thermal Expansion ........................................................................ 13
Temperature-Pressure Relief Valve ............................................... 13
Contaminated Air ...........................................................................14
Air Requirements ........................................................................... 14
Unconned Space .........................................................................15
Conned Space .............................................................................15
Vent Adapter .................................................................................. 15
VENTING INSTALLATION .................................................................15
Venting ...........................................................................................15
Multiple Heater Manifold ................................................................ 16
Fresh Air Openings For Conned Spaces ..................................... 16
Outdoor Air Through Two Openings ..............................................16
Outdoor Air Through One Opening ................................................16
Outdoor Air Through Two Horizontal Ducts ................................... 16
Outdoor Air Through Two Vertical Ducts ........................................ 17
Air From Other Indoor Spaces ....................................................... 17
Technical Data Venting ..................................................................18
WATER HEATER INSTALLATION ...................................................... 19
Water Line Connections ................................................................19
T&P Valve Discharge Pipe ............................................................. 19
Installation Diagrams - Top Inlet/Outlet Usage ..............................20
Code Restrictions ..........................................................................20
Heater Wiring ................................................................................. 21
Gas Piping .....................................................................................22
Purging ..........................................................................................22
Gas Pressure Regulator ................................................................ 22
OPERATION ....................................................................................... 23
General .......................................................................................... 23
Filling .............................................................................................23
SEQUENCE OF OPERATION ........................................................... 23
Lighting & Operation Label ............................................................24
Check Venting ...............................................................................25
Check the Igniter Assembly ........................................................... 25
Igniter Assembly ............................................................................25
Main Burner ...................................................................................25
Gas Valves ..................................................................................... 25
Checking the Input ......................................................................... 26
MAINTENANCE .................................................................................26
Venting System ..............................................................................26
Remote Storage Tank Temperature Control ..................................26
Temperature-Pressure Relief Valve Test ....................................... 26
Hot Water Odor ..............................................................................27
Anode Rod Inspection ...................................................................27
Draining and Flushing .................................................................... 27
Recommended Procedure for Periodic Removal of Lime Deposits
from Tank Type Commercial Water Heaters ..................................28
Deliming Solvents .......................................................................... 28
Tank Cleanout Procedure .............................................................. 28
Deliming Using Flo-Jug Method ....................................................28
Ignition Module System .................................................................30
System Diagnostics ....................................................................... 30
SERVICE ............................................................................................ 30
Electrical Servicing ........................................................................30
FOR YOUR INFORMATION ...............................................................30
Start Up Conditions .......................................................................30
Operational Conditions .................................................................. 30
Sequence of Operation Flow Chart ...............................................32
OPERATIONAL CHECKLIST ............................................................. 33
WATER PIPING DIAGRAMS ..............................................................34
MANIFOLD KITS ................................................................................49
LIMITED WARRANTY ........................................................................ 50
NOTES ............................................................................................... 51
2

SAFE INSTALLATION, USE AND SERVICE

ASME CRN
The proper installation, use and servicing of this water heater is extremely important to your safety and the safety of others.
Many safety-related messages and instructions have been provided in this manual and on your own water heater to warn you and others of a potential injury hazard. Read and obey all safety messages and instructions throughout this manual. It is very important that the meaning of each safety message is understood by you and others who install, use, or service this water heater.
This is the safety alert symbol. It is used to alert you to potential personal injury hazards. Obey all safety messages that follow this symbol to avoid possible injury or death.
DANGER indicates an imminently
DANGER
WARNING
CAUTION
hazardous situation which, if not avoided, will result in injury or death.
WARNING indicates a potentially hazardous situation which, if not avoided, could result in injury or death.
CAUTION indicates a potentially hazardous situation which, if not avoided, could result in minor or moderate injury.
CAUTION used without the safety alert
CAUTION
All safety messages will generally tell you about the type of hazard, what can happen if you do not follow the safety message, and how to avoid the risk of injury.
The California Safe Drinking Water and Toxic Enforcement Act requires the Governor of California to publish a list of substances known to the State of California to cause cancer, birth defects, or other reproductive harm, and requires businesses to warn of potential exposure to such substances.
This product contains a chemical known to the State of California to cause cancer, birth defects, or other reproductive harm. This appliance can cause low level exposure to some of the substances listed in the Act.
symbol indicates a potentially hazardous situation which, if not avoided, could result in property damage.

APPROVALS

Low Lead Content California AB1953
3

GENERAL SAFETY INFORMATION

CAUTION
Fire or Explosion Hazard
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
Avoid all ignition sources if you smell gas.
Do not expose water heater controls to excessive gas pressure.
Use only the gas shown on the water heater rating label. Maintain required clearances to combustibles.
Keep ignition sources away from faucets after extended periods of non-use.
Read instruction manual before
installing, using or servicing
water heater.
Breathing Hazard - Carbon Monoxide Gas
Do not obstruct water heater air intake with insulating blanket.
Gas and carbon monoxide detectors are available.
Install water heater in accordance with the instruction manual.
Breathing carbon monoxide can cause brain damage or death. Always read and understand instruction manual.
Property Damage Hazard
Fire Hazard
For continued protection against risk of fire:
Do not install water heater on carpeted floor.
Do not operate water heater if flood damaged.
Fire and Explosion Hazard
Use joint compound or Teflon tape compatible with propane gas.
Leak test before placing the water heater in operation.
Disconnect gas piping and main gas shutoff valve before leak testing.
Install sediment trap in accordance with NFPA 54.
Fire and Explosion Hazard
Do not use water heater with any gas other than the gas shown on the rating label.
Excessive gas pressure to gas valve can cause serious injury or death.
Turn off gas lines during installation. Contact a qualified installer or service
agency for installation and service.
All water heaters eventually leak.
Do not install without adequate drainage.
Electrical Shock Hazard
Turn off power to the water heater
before performing any service.
Label all wires prior to disconnecting
when performing service. Wiring errors can cause improper and dangerous operation.
Verify proper operation after servicing.
Failure to follow these instructions can
result in personal injury or death.
Jumping out control circuits or components can
result in property damage, personal injury or death.
Service should only be performed by a qualified service
agent using proper test equipment.
Altering the water heater controls and/or wiring in any way
could result in permanent damage to the controls or water heater and is not covered under the limited warranty.
Altering the water heater controls and/or wiring in any way
could result in altering the ignition sequence allowing gas to flow to the main burner before the hot surface igniter is at ignition temperature causing delayed ignition which can cause a fire or explosion.
Any bypass or alteration of the water
heater controls and/or wiring will result
in voiding the appliance warranty.
4
GENERAL SAFETY INFORMATION
Read and understand this instruction manual and the safety messages herein before installing, operating or servicing this water heater.
Failure to follow these instructions and safety messages could result in death or serious injury.
This manual must remain with the water heater.
Water temperature over 125°F (52°C) can cause severe burns instantly resulting in severe injury or death.
Children, the elderly and the physically or mentally disabled are at highest risk for scald injury.
Feel water before bathing or showering.
Temperature limiting devices such as mixing valves must be installed when required by codes and to ensure safe temperatures at fixtures.
Explosion Hazard
Overheated water can cause water tank explosion.
Properly sized temperature and pressure relief valve must be installed in the opening provided.
CAUTION
Improper installation, use and service may result
in property damage.
Do not operate water heater if flood damaged.
Inspect and anode rods regularly, replace if damaged.
Install in location with drainage.
Fill tank with water before operation.
Properly sized thermal expansion tanks are required on all
closed water systems.
Refer to this manual for installation and service.
Verify the power to the water heater is turned off before performing any service procedures.
GENERAL SAFETY INFORMATION

PRECAUTIONS

DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN
UNDER WATER. Immediately call a qualied service agency to inspect the appliance and to make a determination on what steps should be taken next.
If the unit is exposed to the following, do not operate heater
until all corrective steps have been made by a qualified service agency.
1. External re.
2. Damage.
3. Firing without water.

GROUNDING INSTRUCTIONS

This water heater must be grounded in accordance with the National Electrical Code and/or local codes. These must be followed in all cases.
This water heater must be connected to a grounded metal, permanent wiring system; or an equipment grounding conductor must be run with the circuit conductors and connected to the
equipment grounding terminal or lead on the water heater, see
Figure 20.

HYDROGEN GAS FLAMMABLE

Explosion Hazard
Flammable hydrogen gases may be present.
Keep all ignition sources away from faucet when turning on hot water.
Hydrogen gas can be produced in a hot water system served by this appliance that has not been used for a long period of time (generally two weeks or more). Hydrogen gas is extremely ammable. To reduce the risk of injury under these conditions, it is recommended that a hot water faucet served by this appliance be opened for several minutes before using any electrical appliance connected to the hot water system. If hydrogen is present there will probably be an unusual sound such as air escaping through the pipe as the water begins to ow. THERE SHOULD BE NO
SMOKING OR OPEN FLAME NEAR THE FAUCET AT THE
TIME IT IS OPEN.
5

INTRODUCTION

Thank You for purchasing this water heater. Properly installed and maintained, it should give you years of trouble free service.

ABBREVIATIONS USED

Abbreviations found in this Instruction Manual include :
• ANSI - American National Standards Institute
• ASME - American Society of Mechanical Engineers
• GAMA - Gas Appliance Manufacturer’s Association
• NEC - National Electrical Code
• NFPA - National Fire Protection Association
UL - Underwriters Laboratory
• CSA - Canadian Standards Association

QUALIFICATIONS

QUALIFIED INSTALLER OR SERVICE AGENCY
Installation and service of this water heater requires ability equivalent to that of a Qualied Agency (as dened by ANSI
below) in the eld involved. Installation skills such as plumbing, air supply, venting, gas supply and electrical supply are required in addition to electrical testing skills when performing service.
ANSI Z223.1 2006 Sec. 3.3.83: “Qualied Agency” - “Any individual, rm, corporation or company that either in person
or through a representative is engaged in and is responsible
for (a) the installation, testing or replacement of gas piping or (b) the connection, installation, testing, repair or servicing of appliances and equipment; that is experienced in such work; that is familiar with all precautions required; and that has complied with all the requirements of the authority having jurisdiction.”
If you are not qualied (as dened by ANSI above) and licensed or certied as required by the authority having jurisdiction
to perform a given task do not attempt to perform any of the
procedures described in this manual. If you do not understand the instructions given in this manual do not attempt to perform any procedures outlined in this manual.
6

FEATURES AND COMPONENTS

THE HYDRO CANNON (SELF-CLEANING SYSTEM)

These units include The Hydro Cannon (Self-Cleaning System) installed in the front water inlet, See Figure 1. The Hydro Cannon inlet tube can only be used in the front water inlet connection. Do not install the Hydro Cannon inlet tube in either the top or back inlet water connection. The Hydro Cannon must be oriented correctly for proper function. There is a marked range on the pipe nipple portion
of the Hydro Cannon, that must be aligned with the top of the inlet
spud. A label above the jacket hole has an arrow that will point to the marked portion of the pipe nipple if the orientation is correct.
If the arrow does not point within the marked range on the pipe
nipple, adjust the pipe nipple to correct. A pipe union is supplied with the Hydro Cannon to reduce the probability of misaligning the Hydro Cannon accidentally while tightening the connection to the inlet water supply line. Improper orientation of the Hydro Cannon can cause poor performance of the heater and can signicantly reduce outlet water temperatures during heavy draws.
Note: The Hydro Cannon may have 1, 3 or 7 cross tubes.
FIGURE 1

HIGH LIMIT SWITCH

The digital thermostat (Figure 2) contains the high limit (energy cutoff) switch. The high limit switch interrupts main burner gas ow should the water temperature reach 203°F (95°C).
In the event of high limit switch operation, the appliance cannot be restarted unless the water temperature is reduced to approximately 120°F (49°C). The high limit reset button on the front of the control then needs to be depressed.
Continued manual resetting of high limit control, preceded by higher than usual water temperature is evidence of high limit switch operation. The following is a possible reason for high limit switch operation:
• A malfunction in the thermostatic controls would allow the gas valve to remain open causing water temperature to exceed the thermostat setting. The water temperature would continue to rise until high limit switch operation.
Contact your dealer or service agent if continued high limit switch operation occurs.

ELECTRONIC IGNITION CONTROL

Each heater is equipped with an ignition module. The solid state ignition control (Figure 3), ignites the main burner by utilizing a silicon nitride igniter. The silicon nitride igniter shuts off during the heating cycle and the main burner ame is sensed through a remote ame sensor integral to the silicon nitride igniter assembly.
The ignition control will try to ignite the main burner three times bef o r e lo cko u t . Th e n it waits one hour before tr y i n g ag a i n to ig n i te the main burners. This is a continuous cycle.
IGNITION CONTROL BOARD
FIGURE 3

EXHAUST INDUCER (BLOWER ASSY.)

All models are equipped with an exhaust inducer. The inducer assists in drawing in fresh air to the unit for combustion and then assists in dispensing the combustion by-products into the venting leading outside.
The exhaust inducer is equipped with a gravity controlled damper to reduce the amount of heat loss through the ue, improving efciency.
DIGITAL THERMOSTAT
FIGURE 2
EXHAUST INDUCER
FIGURE 4

UNCRATING

The heater is shipped with the inducer already installed. The wiring conduit runs from the thermostat to the inducer. Before turning unit on, check to make sure the wiring conduit is securely plugged into the inducer.
7

INSTALLATION CONSIDERATIONS

ROUGH IN DIMENSIONS

RECOVERY CAPACITIES

GAS AND ELECTRICAL CHARACTERISTICS

FRONT VIEW
TOP
OUTLET
1 1/2” NPT
TOP VIEW
FIGURE 5
TABLE 1. ROUGH-IN-DIMENSIONS
Dimensions in Inches/cm
Recovery Rating Capacities (GPH and LPH) at temperature rise indicated
Model
SBD85500NE/
SBD85500PE
SBD85500NE/
SBD85500PE
Input Rate
Btu/Hr Kw/Hr
500,000 85 81.50 17.50 77.25 67.50 27.13 21.00 1.00 67.50 8.00 27.75 1.50 1.50 1.50 1.50 1.50 1.50 812 857
Approximate
Tank Cap
G/L
147 322 207 44 196 171 69 53 3 171 20 70 1.50 1.50 1.50 1.50 1.50 1.50 368 389
A B C D E F
TABLE 2. RECOVERY CAPACITIES, based on 80% efciency
Model
SBD85500NE/
SBD85500PE
SBD85500NE/
SBD85500PE
Input Rate
Btu/Hr Kw/Hr
500,000 85 1616 1212 970 808 693 606 539 485 441 404 373 346
147 322 6118 4588 3671 3059 2622 2294 2039 1835 1668 1529 1412 1311
Approximate
Tank Cap
G/L
30°F 40°F 50°F 60°F 70°F 80°F 90°F 100°F 110°F 120°F 130°F 140°F 17°C 22°C 28°C 33°C 39°C 44°C 50°C 56°C 61°C 67°C 72°C 78°C
F
Gas Inlet GH
BACK VIEW
TOP
INLET
1 1/2” NPT
Connections
Vent
Dia IJ Top Front Back To p Front Back
Inlet (NPT) Outlet (NPT)
Approx. Ship Weight
Std.
Lbs/
Kgs.
ASME
Lbs/
Kgs.
TABLE 3. GAS AND ELECTRICAL CHARACTERISTICS
Model Gas Type
SBD85500NE/
SBD85500PE
SBD85500NE/
SBD85500PE
Minumum Maximum
Natural 4.5" W.C. (1.12 kPa) 14" W.C. (3.48 kPa) 3.5" W.C. (0.87 kPa) 120/60 <5
Propane 11" W.C. (2.74 kPa) 14" W.C. (3.48 kPa) 10" W.C. (2.49 kPa) 120/60 <5
Gas Supply Pressure
Gas Manifold Pressure Volts / Hz Amperes
8
CAUTION
INSTALLATION CONSIDERATIONS

LOCATING THE WATER HEATER

Property Damage Hazard
All water heaters eventually leak.
Do not install without adequate drainage.
When installing the heater, consideration must be given to proper location. Location selected should be as close to the stack or chimney as practicable, with adequate air supply and as centralized with the piping system as possible.
Fire or Explosion Hazard
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
Avoid all ignition sources if you smell gas.
Do not expose water heater controls to excessive gas pressure.
Use only the gas shown on the water heater rating label. Maintain required clearances to combustibles.
Keep ignition sources away from faucets after extended periods of non-use.
Read instruction manual before
installing, using or servicing
water heater.
THERE IS A RISK IN USING FUEL BURNING APPLIANCES SUCH AS GAS WATER HEATERS IN ROOMS, GARAGES OR OTHER AREAS WHERE GASOLINE, OTHER FLAMMABLE LIQUIDS OR ENGINE DRIVEN EQUIPMENT OR VEHICLES ARE
STORED, OPERATED OR REPAIRED. FLAMMABLE VAPORS
ARE HEAVY AND TRAVEL ALONG THE FLOOR AND MAY BE
IGNITED BY THE HEATER’S PILOT OR MAIN BURNER FLAMES CAUSING FIRE OR EXPLOSION. SOME LOCAL CODES
PERMIT OPERATION OF GAS APPLIANCES IN SUCH AREAS
IF THEY ARE INSTALLED 18” OR MORE ABOVE THE FLOOR.
THIS MAY REDUCE THE RISK IF LOCATION IN SUCH AN AREA
CANNOT BE AVOIDED.
DO NOT INSTALL THIS WATER HEATER DIRECTLY ON A CARPETED FLOOR. A FIRE HAZARD MAY RESULT. Instead the
water heater must be placed on a metal or wood panel extending beyond the full width and depth by at least 3 inches in any direction. If the heater is installed in a carpeted alcove, the entire oor shall be covered by the panel. Also, see the DRAINING requirements in MAINTENANCE Section.
THE HEATER SHALL BE LOCATED OR PROTECTED SO IT
IS NOT SUBJECT TO PHYSICAL DAMAGE BY A MOVING
VEHICLE.
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST
NEVER BE PLACED ON OR ADJACENT TO THE HEATER.
OPEN CONTAINERS OR FLAMMABLE MATERIAL SHOULD NOT BE STORED OR USED IN THE SAME ROOM WITH THE
HEATER.
THE HEATER MUST NOT BE LOCATED IN AN AREA WHERE
IT WILL BE SUBJECT TO FREEZING.
LOCATE IT NEAR A FLOOR DRAIN. THE HEATER SHOULD
BE LOCATED IN AN AREA WHERE LEAKAGE FROM THE HEATER OR CONNECTIONS WILL NOT RESULT IN DAMAGE TO THE ADJACENT AREA OR TO LOWER FLOORS OF THE
STRUCTURE.
WHEN SUCH LOCATIONS CANNOT BE AVOIDED, A SUITABLE
DRAIN PAN SHOULD BE INSTALLED UNDER THE HEATER. Such pans should be fabricated with sides at least 2” deep, with length and width at least 2” greater than the diameter of the heater and must be piped to an adequate drain. The pan must not restrict combustion air ow.

CLEARANCES

This water heater is approved for installation on combustible ooring (with NSF Leg Kit #9003425205) in an alcove when the minimum clearance from any combustible construction is as indicated in Figure 6 and Table 4.
In all installations the minimum combustible clearances from vent piping shall be 6” (15.2 cm). Vent piping passing through a combustible wall or ceiling must be a continuous run (no joints) and retain the 6” (15.2 cm) clearance unless an approved reducing thimble is used.
A service clearance of 24” (61 cm) should be maintained from serviceable parts, such as relief valves, ue bafes, thermostats, cleanout openings or drain valves.
The units are approved for installation with side, rear and ceiling clearances as indicated below:
TABLE 4
MINIMUM CLEARANCES TO COMBUSTIBLES IN INCHES (mm)
"A"
MODEL
SBD85500NE/
SBD85500PE
MINIMUM CLEARANCES TO NONCOMBUSTIBLE CONSTRUCTION
MODEL
SBD85500NE/
SBD85500PE
RIGHT
SIDE
5"
(12.7 cm)
"A"
RIGHT
SIDE
0 0 0
"B"
LEFT
SIDE
5"
(12.7 cm)
TABLE 5
"B"
LEFT
SIDE
"C"
BACK
5"
(12.7 cm)
"C"
BACK
"D"
CEILING
20"
(50.8 cm)
"D"
CEILING
12"
(30.5 cm)
9
FIGURE 6

INSULATION BLANKET

Breathing Hazard - Carbon Monoxide Gas
Do not obstruct water heater air intake with insulating blanket.
Gas and carbon monoxide detectors are available.
Install water heater in accordance with the instruction manual.
Breathing carbon monoxide can cause brain damage or death. Always read and understand instruction manual.
Insulation blankets are available to the general public for external use on gas water heaters but are not necessary with these products. The purpose of an insulation blanket is to reduce the standby heat loss encountered with storage tank heaters. The water heaters covered by this manual meet or exceed the Energy Policy Act standards with respect to insulation and standby heat loss requirements, making an insulation blanket unnecessary.
Should you choose to apply an insulation blanket to this heater, you should follow these instructions. See the Features and Components section of this manual for identication of components mentioned below. Failure to follow these instructions can restrict the air ow required for proper combustion, potentially resulting in re, asphyxiation, serious personal injury or death.

INSTALLATION ON COMBUSTIBLE FLOORING

The SBD85500NE/SBD85500PE is approved for installations
on combustible ooring when installed with NSF Leg Kit number
9003425205
FIGURE 7
1. Unit needs to be lifted in a way not to damage unit or laid on it’s side to access the bottom of the legs.
2. Slide leg extension under leg and the bolt up through the bottom hole located in the bottom of the leg.
3. Once in place, screw nut down and secure.
4. Front of leg should line up with front of leg extension as
shown in Figure 7 to make sure weight of unit is distributed
through the leg extension.
DO NOT apply insulation to the top of the water heater, as this
will interfere with safe operation of the exhaust inducer.
DO NOT cover the gas valve, thermostat or the Temperature­Pressure Relief Valve.
DO NOT allow insulation to come within 2” (5 cm) of the burners, to prevent blockage of combustion air ow to the burners.
DO NOT allow insulation to come within 9 inches (23 cm) of oor, (within 2 inches (5 cm) of bottom cover) to prevent blockage of combustion air ow to the burners..
DO NOT cover the instruction manual. Keep it on the side of the water heater or nearby for future reference.
DO obtain new warning and instruction labels from the manufacturer for placement on the blanket directly over the existing labels.
DO inspect the insulation blanket frequently to make certain it does not sag, thereby obstructing combustion air ow.

HARD WATER

Where hard water conditions exist, water softening or the threshold type of water treatment is recommended. This will protect the dishwashers, coffee urns, water heaters, water piping and other equipment.
See the Maintenance Section in this manual for sediment and lime scale removal procedures.

CIRCULATION PUMPS

A circulating pump is used when a system requires a circulating loop or there is a storage tank used in conjunction with the water heater. See Water Piping Diagrams in this manual for installation location of circulating pumps.
10
See the Circulation Pump Wiring Diagrams (Figure 8, Figure
CIRCULATING PUMP WIRING DIAGRAM
DISHWASHER LOOP WITH TOGGLE SWITCH
FIELD SUPPLIED TEMPERATURE CONTROL INSTALLED IN THE CIRCULATING LOOP RETURN LINE
DISHWASHER TOGGLE SWITCH
CIRC
PUMP
MOTOR
L1 HOT
120 VAC POWER
NOTE: USE SEPARATE 120 VAC POWER SUPPLY FOR PUMP CIRCUIT. DO NOT SHARE POWER WITH APPLIANCE AS THIS MAY CAUSE ELECTRICAL LINE NOISE AND LEAD TO ERRATIC CONTROL SYSTEM OPERATION.
9) in this manual for electrical hookup information. Install in accordance with the current edition of the National Electrical Code, NFPA 70 or the Canadian Electrical Code, CSA C22.1.
All-bronze circulators are recommended for used with commercial water heaters.
Some circulating pumps are manufactured with sealed bearings and do not require further lubrication. Some circulating pumps must be periodically oiled. Refer to the pump manufacturer’s instructions for lubrication requirements.
CIRCULATING PUMP WIRING DIAGRAM
STORAGE TANK OR BUILDING RECIRCULATION
FIELD SUPPLIED TEMPERATURE CONTROL INSTALLED IN THE STORAGE TANK
NOTE: USE SEPARATE 120 VAC POWER SUPPLY FOR PUMP CIRCUIT. DO NOT SHARE POWER WITH APPLIANCE AS THIS MAY CAUSE ELECTRICAL LINE NOISE AND LEAD TO ERRATIC CONTROL SYSTEM OPERATION.
L1 HOT
120 VAC POWER
L2 NEUTRAL
OR CIRCULATING LOOP RETURN LINE
CIRC
PUMP
MOTOR
FIGURE 8.
CIRCULATING PUMP WIRING DIAGRAM
DISHWASHER LOOP WITH TOGGLE SWITCH
DISHWASHER TOGGLE SWITCH
NOTE: USE SEPARATE 120 VAC POWER SUPPLY FOR PUMP CIRCUIT. DO NOT SHARE POWER WITH APPLIANCE AS THIS MAY CAUSE ELECTRICAL LINE NOISE AND LEAD TO ERRATIC CONTROL SYSTEM OPERATION.
L1 HOT
120 VAC POWER
L2 NEUTRAL
FIELD SUPPLIED TEMPERATURE CONTROL INSTALLED IN THE CIRCULATING LOOP RETURN LINE
CIRC
PUMP
MOTOR
FIGURE 9.

HIGH ALTITUDE INSTALLATIONS

Fire and Explosion Hazard
Under no circumstances should the input exceed the rate shown on the water heater’s rating label.
Overfiring could result in fire or explosion.
Gas and carbon monoxide detectors are available.
Breathing Hazard - Carbon Monoxide Gas
Under no circumstances should the input exceed the rate shown on the water heater’s rating label.
Overfiring could result in damage to the water heater and sooting.
Gas and carbon monoxide detectors are available.
Breathing carbon monoxide can cause brain damage or death. Always read and understand instruction manual.

PROPANE INSTALLATIONS

INSTALLATIONS ABOVE 2000 FEET (610 METERS) REQUIRE
REPLACEMENT OF BURNER ORIFICES IN ACCORDANCE WITH CURRENT EDITION OF THE NATIONAL FUEL GAS CODE
(ANSI Z223.1). FOR CANADIAN INSTALLATIONS CONSULT CANADIAN INSTALLATIONS CODE CAN/CSA B149.1. FAILURE
TO REPLACE ORIFICES WILL RESULT IN IMPROPER AND INEFFICIENT OPERATION OF THE APPLIANCE RESULTING IN THE PRODUCTION OF INCREASED LEVELS OF CARBON MONOXIDE GAS IN EXCESS OF SAFE LIMITS WHICH COULD
RESULT IN SERIOUS PERSONAL INJURY OR DEATH.
You should contact your gas supplier for any specic changes which may be required in your area.
As elevation above sea level is increased, there is less oxygen per cubic foot of air. Therefore, the heater input rate should be reduced at high altitudes for satisfactory operation with the reduced oxygen supply. Failure to make this reduction would result in an over ring of the heater causing sooting, poor combustion and/or unsatisfactory heater performance.
Ratings specied by manufacturers for most appliances apply for elevations up to 2000 feet (610m). For elevations above 2000 feet (610), ratings must be reduced at the rate of 4% for each 1000 feet (305m) above sea level. For example, if a heater is rated at 78,000 Btuh (22.9 Kwh) at sea level, to rate the heater at 4000 feet (1219m), you subtract 4 (once for each thousand feet) x.04 (4% input reduction) x 78,000 (original rating) from the original rating.
Therefore, to calculate the input rating at 4,000 feet (1219m): 4 x .04 x 78,000 = 12,480 Btuh (3.7 Kwh), 78,000 (22.9 Kwh) - 12,480 (3.7 Kwh) = 65,520 Btuh (19.2 Kwh). At 6000 feet (1829m) the correct input rating should be 59,280 Btuh (17.4 Kwh).

NATURAL GAS INSTALLATIONS

The natural gas red version of the water heater covered by this manual is certied for use without modication for altitudes up to 10,100 feet.
For installations above 10,100 feet call the technical support phone number listed on the back cover of this manual for further technical assistance. Call the local gas or utility company to verify Btu per cubic foot content before calling for technical assistance and have that information available.
Note: The actual ring rate of the water heater must not exceed
the input rating on the water heater's rating label under any
circumstances.
Note: Due to the input rating reduction at high altitudes, the output rating of the appliance is also reduced and should be compensated for in the sizing of the equipment for applications.
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INSTALLATION REQUIREMENTS

GAS PRESSURE REQUIREMENTS

Natural gas models require a minimum gas supply pressure of
4.5” W.C. Propane gas models require a minimum gas supply pressure of 11" W.C. The minimum supply pressure is measured while gas is not owing (static pressure) AND while gas is owing (dynamic pressure). The supply pressure (static and dynamic) should never fall below the specied minimum supply pressure. The supply pressure should be measured with all gas red appliances connected to the common main ring at full capacity. If the supply pressure drops more than 1.5” W.C. as gas begins to ow to the water heater then the supply gas system including the gas line and/or the gas regulator may be restricted or undersized. See Supply Gas Regulator section and Gas Piping section of this manual.
The gas valve on all models has a maximum gas supply
pressure limit of 14" W.C. The maximum supply pressure is measured while gas is not owing (static pressure) AND while gas is owing (dynamic pressure).

SUPPLY GAS REGULATOR

The water heater covered by this manual may require the installation of a supply gas regulator. If the supply gas pressure exceeds 14 inches W.C. a supply gas regulator must be used. If the gas supply pressure exceeds 14" W.C. in a multiple water heater installation, each water heater must have its own supply gas regulator. If required, the supply gas
regulator shall be rated at or above the Btu/hr input rating of
the water heater it supplies.
Supply gas regulators shall have inlet and outlet connections
not less than the minimum supply gas line size for the water
heater they serve as shown in Table 9. The Maxitrol 325-7L or equivalent is recommended.

POWER SUPPLY

The water heaters covered in this manual require a 120 VAC, 1Ø (single phase), 60Hz, 15 amp power supply and must also be electrically grounded in accordance with local codes or, in the absence of local codes, with the National Electrical Code, ANSI/NFPA 70 or the Canadian Electrical Code, CSA C22.1.

WATER TEMPERATURE CONTROL AND MIXING VALVES

Water temperature over 125°F (52°C) can cause severe burns instantly resulting in severe injury or death.
Children, the elderly and the physically or mentally disabled are at highest risk for scald injury.
Feel water before bathing or showering.
Temperature limiting devices such as mixing valves must be installed when required by codes and to ensure safe temperatures at fixtures.
Water heated to a temperature which will satisfy clothes washing, dish washing, and other sanitizing needs can scald and cause permanent injury upon contact. Short repeated heating cycles caused by small hot water uses can cause temperatures at the point of use to exceed the water heater’s temperature setting by up to 20°F (11°C).
Some people are more likely to be permanently injured by
hot water than others. These include the elderly, children, the inrm and the physically/mentally disabled. Table 6 shows the approximate time-to-burn relationship for normal adult skin. If
anyone using hot water provided by the water heater being
installed ts into one of these groups or if there is a local code or state law requiring a certain water temperature at the point of use, then special precautions must be taken.
In addition to using the lowest possible temperature setting
that satises the demand of the application a Mixing Valve should be installed at the water heater (see Figure 10) or at the hot water taps to further reduce system water temperature.
Mixing valves are available at plumbing supply stores. Consult a Qualied Installer or Service Agency. Follow mixing valve manufacturer’s instructions for installation of the valves.
TABLE 6.
Water Temperature
180°F (82°C) Nearly instantaneous 170°F (77°C) Nearly instantaneous
160°F (71°C) About 1/2 second
150°F (66°C) About 1-1/2 seconds 140°F (60°C) Less than 5 seconds 130°F (54°C) About 30 seconds 120°F (49°C) More than 5 minutes
Time to Produce 2nd & 3rd
Degree Burns on Adult Skin
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HOT WATER
OUTLET
TEMPERED WATER
OUTLET
12” TO 15” (30-38 cm)
A properly sized thermal expansion tank must be installed on
all closed systems to control the harmful effects of thermal expansion. Contact a local plumbing service agency to have a thermal expansion tank installed.
See Water Line Connections on page 19 and the Water Piping Diagrams beginning on page 34.

TEMPERATURE-PRESSURE RELIEF VALVE

COLD
WATER
INLET
CHECK
VALV E
TO TANK
INLET
FIGURE 10
CHECK
VALV E
MIXING
VALV E

DISHWASHING MACHINES

All dishwashing machines meeting the National Sanitation
Foundation requirements are designed to operate with water
ow pressures between 15 and 25 pounds per square inch (103 kPa and 173 kPa). Flow pressures above 25 pounds per square inch (173 kPa), or below 15 pounds per square inch (103 kPa), will result in improperly sanitized dishes. Where pressures are high, a water pressure reducing or ow regulating control valve should be used in the 180°F (82°C) line to the dishwashing machine and should be adjusted to deliver water pressure between these limits.
The National Sanitation Foundation also recommends circulation of 180°F (82°C) water. Where this is done, the circulation should be very gentle so that it does not cause any unnecessary turbulence inside the water heater. The circulation should be just enough to provide 180°F (82°C) water at the point of take-off to the dishwashing machine.
Adjust ow by throttling a full port ball valve installed in the circulating line on the outlet side of the pump. Never throttle ow on the suction side of a pump. See Water Piping Diagrams in this manual.

CLOSED WATER SYSTEMS

Water supply systems may, because of code requirements or such conditions as high line pressure, among others, have installed devices such as pressure reducing valves, check valves, and back ow preventers. Devices such as these cause the water system to be a closed system.

THERMAL EXPANSION

As water is heated, it expands (thermal expansion). In a closed system the volume of water will grow when it is heated. As the volume of water grows there will be a corresponding increase in water pressure due to thermal expansion. Thermal expansion can cause premature tank failure (leakage). This type of failure is not covered under the limited warranty. Thermal expansion can also cause intermittent Temperature-Pressure Relief Valve operation: water discharged from the valve due to excessive pressure build up. This condition is not covered under the limited warranty. The Temperature-Pressure Relief Valve is not intended for the constant relief of thermal expansion.
Explosion Hazard
Temperature-Pressure Relief Valve must comply with ANSI Z21.22­CSA 4.4 and ASME code.
Properly sized temperature­pressure relief valve must be installed in opening provided.
Can result in overheating and excessive tank pressure.
Can cause serious injury or death.
This water heater is provided with a properly rated/sized and
certied combination Temperature-Pressure Relief Valve (T&P valve) by the manufacturer. The valve is certied by a nationally recognized testing laboratory that maintains periodic inspection of production of listed equipment of materials as meeting the
requirements for Relief Valves for Hot Water Supply Systems,
ANSI Z21.22 • CSA 4.4, and the code requirements of ASME.
If replaced, the new T&P valve must meet the requirements of local codes, but not less than a combination Temperature­Pressure Relief Valve rated/sized and certied as indicated in the above paragraph. The new valve must be marked with a maximum set pressure not to exceed the marked hydrostatic working pressure of the water heater (150 psi = 1,035 kPa) and a discharge capacity not less than the water heater Btu/hr or kW input rate as shown on the water heater’s model rating label.
NOTE: In addition to the factory installed Temperature-Pressure Relief Valve on the water heater, each remote storage tank that may be installed and piped to a water heating appliance must also
have its own properly sized, rated and approved Temperature-
Pressure Relief Valve installed. Call the toll free technical support phone number listed on the back cover of this manual for technical assistance in sizing a Temperature-Pressure Relief Valve for remote storage tanks.
For safe operation of the water heater, the Temperature-Pressure Relief Valve must not be removed from its designated opening
nor plugged. The Temperature-Pressure Relief Valve must be installed directly into the tting of the water heater designed for the relief valve. Install discharge piping so that any discharge will exit the pipe within 6 inches (15.2 cm) above an adequate oor drain, or external to the building. In cold climates it is recommended that it be terminated at an adequate drain inside the building. Be certain that no contact is made with any live electrical part. The discharge opening must not be blocked or reduced in size under any circumstances. Excessive length, over 30 feet (9.14 m), or use of more than four elbows can cause restriction and reduce the discharge capacity of the valve.
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No valve or other obstruction is to be placed between the
CAUTION
Temperature-Pressure Relief Valve and the tank. Do not connect discharge piping directly to the drain unless a 6” (15.2 cm) air gap is provided. To prevent bodily injury, hazard to life, or property damage, the relief valve must be allowed to discharge water in adequate quantities should circumstances demand. If the discharge pipe is not connected to a drain or other suitable means, the water ow may cause property damage.
Water Damage Hazard
Temperature-Pressure Relief Valve discharge
pipe must terminate at adequate drain.
T&P Valve Discharge Pipe Requirements:
Shall not be smaller in size than the outlet pipe size of the valve, or have any reducing couplings or other restrictions.
• Shall not be plugged or blocked.
• Shall not be exposed to freezing temperatures.
• Shall be of material listed for hot water distribution.
• Shall be installed so as to allow complete drainage of both the Temperature-Pressure Relief Valve and the discharge pipe.
• Must terminate a maximum of six inches above a oor drain or external to the building. In cold climates, it is recommended that the discharge pipe be terminated at an adequate drain inside the building.
• Shall not have any valve or other obstruction between the relief valve and the drain.
If you do not understand these instructions or have any questions regarding the Temperature-Pressure Relief Valve call the toll free number listed on the back cover of this manual for technical assistance.

CONTAMINATED AIR

Breathing Hazard - Carbon Monoxide Gas
Install water heater in accordance with the Instruction Manual and NFPA 54 or CAN/CSA-B149.1.
To avoid injury, combustion and ventilation air must be taken from outdoors.
Do not place chemical vapor emitting products near water heater.
Breathing carbon monoxide can cause brain damage or death. Always read and understand instruction manual.
Corrosion of the ue ways and vent system may occur if air for combustion contains certain chemical vapors. Such corrosion may result in failure and risk of asphyxiation.
Combustion air that is contaminated can greatly diminish the life span of the water heater and water heater components such as hot surface igniters and burners. Propellants of aerosol sprays, beauty shop supplies, water softener chemicals and chemicals used in dry cleaning processes that are present in the combustion, ventilation or ambient air can cause such damage.
Do not store products of this sort near the water heater. Air which is brought in contact with the water heater should not contain any of these chemicals. If necessary, uncontaminated air should be obtained from remote or outdoor sources. The limited warranty is voided when failure of water heater is due to a corrosive atmosphere. (See limited warranty for complete terms and conditions).
Burn hazard.
Hot water discharge.
Keep clear of Temperature­Pressure Relief Valve discharge outlet.
The Temperature-Pressure Relief Valve must be manually
operated at least twice a year. Caution should be taken to ensure that (1) no one is in front of or around the outlet of the Temperature­Pressure Relief Valve discharge line, and (2) the water manually discharged will not cause any bodily injury or property damage because the water may be extremely hot. If after manually operating the valve, it fails to completely reset and continues to release water, immediately close the cold water inlet to the water heater, follow the draining instructions in this manual, and replace
the Temperature-Pressure Relief Valve with a properly rated/sized
new one.
NOTE: The purpose of a Temperature-Pressure Relief Valve is
to prevent excessive temperatures and pressures in the storage tank. The T&P valve is not intended for the constant relief of thermal expansion. A properly sized thermal expansion tank must be installed on all closed systems to control thermal expansion, see Closed Water Systems and Thermal Expansion on page 13.

AIR REQUIREMENTS

Breathing Hazard - Carbon Monoxide Gas
Install water heater in accordance with the Instruction Manual and NFPA 54 or CAN/CSA-B149.1.
To avoid injury, combustion and ventilation air must be taken from outdoors.
Do not place chemical vapor emitting products near water heater.
Breathing carbon monoxide can cause brain damage or death. Always read and understand instruction manual.
For safe operation an adequate supply of fresh uncontaminated air for combustion and ventilation must be provided.
An insufcient supply of air can cause recirculation of combustion products resulting in contamination that may be hazardous to life. Such a condition often will result in a yellow, luminous burner ame, causing sooting of the combustion chamber, burners and ue tubes and creates a risk of asphyxiation.
Do not install the water heater in a conned space unless an adequate supply of air for combustion and ventilation is brought in to that space using the methods described in the Conned Space section that follows.
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Never obstruct the ow of ventilation air. If you have any doubts or questions at all, call your gas supplier. Failure to provide the proper amount of combustion air can result in a re or explosion and cause property damage, serious bodily injury or death.

UNCONFINED SPACE

An Unconned Space is one whose volume IS NOT LESS THAN 50 cubic feet per 1,000 Btu/hr (4.8 cubic meters per kW) of the total input rating of all appliances installed in the space. Rooms communicating directly with the space, in which the appliances
are installed, through openings not furnished with doors, are
considered a part of the unconned space.
Makeup air requirements for the operation of exhaust fans,
kitchen ventilation systems, clothes dryers and replaces shall also be considered in determining the adequacy of a space to provide combustion, ventilation and dilution air.
UNUSUALLY TIGHT CONSTRUCTION
In unconned spaces in buildings, inltration may be adequate to provide air for combustion, ventilation and dilution of ue gases. However, in buildings of unusually tight construction (for example, weather stripping, heavily insulated, caulked, vapor barrier, etc.) additional air must be provided using the methods described in the Conned Space section that follows.

CONFINED SPACE

A Conned Space is one whose volume IS LESS THAN 50 cubic feet per 1,000 Btu/hr (4.8 cubic meters per kW) of the total input rating of all appliances installed in the space.
Openings must be installed to provide fresh air for combustion, ventilation and dilution in conned spaces. The required size for
the openings is dependent on the method used to provide fresh
air to the conned space AND the total Btu/hr input rating of all appliances installed in the space.
EXHAUST FANS
Where exhaust fans are installed, additional air shall be provided
to replace the exhausted air. When an exhaust fan is installed in the same space with a water heater, sufcient openings to provide fresh air must be provided that accommodate the requirements for all appliances in the room and the exhaust fan. Undersized openings will cause air to be drawn into the room
through the water heater’s vent system causing poor combustion. Sooting, serious damage to the water heater and the risk of re or explosion may result. It can also create a risk of asphyxiation.
LOUVERS AND GRILLES
The free areas of the fresh air openings in the instructions that follow do not take in to account the presence of louvers, grilles or screens in the openings.
The required size of openings for combustion, ventilation and dilution air shall be based on the “net free area” of each opening. Where the free area through a design of louver or grille or screen is known, it shall be used in calculating the size of opening required to provide the free area specied.
Where the louver and grille design and free area are not
known, it shall be assumed that wood louvers will have 25% free area and metal louvers and grilles will have 75% free area. Non motorized louvers and grilles shall be xed in the open position.

VENT ADAPTER

The SBD85500NE/SBD85500PE model is shipped with a 6" to 8" diameter vent adapter (Fig. 11). The vent adapter ts on top of the installed blower exhaust. Use only vent adapters supplied with the unit. The venting must comply with the NATIONAL FUEL GAS CODE, ANSI Z223.1/NFPA 54 and for Canadian installations consult the Canadian Installation Code CAN/CSA B149.1-00.
FIGURE 11

VENTING INSTALLATION

VENTING

THE INSTRUCTIONS IN THIS SECTION ON VENTING MUST BE FOLLOWED TO AVOID CHOKED COMBUSTION OR
RECIRCULATION OF FLUE GASES. SUCH CONDITIONS CAUSE SOOTING OR RISKS OF FIRE AND ASPHYXIATION.
Heater must be protected from freezing downdrafts.
Remove all soot or other obstructions from the chimney that will retard a free draft.
Type B venting is recommended with these heaters. For typical venting application see TECHNICAL DATA VENTING on page 18.
This water heater must be vented in compliance with all local codes, the current revision of the National Fuel Gas Code (ANSI-Z223.1) and with the Category I Venting Tables.
If any part of the vent system is exposed to ambient temperatures
below 40°F it must be insulated to prevent condensation.
• Do not connect the heater to a common vent or chimney with solid fuel burning equipment. This practice is prohibited by many local building codes as is the practice of venting gas fired equipment to the duct work of ventilation systems.
FIGURE 12
• Where a separate vent connection is not available and the vent pipe from the heater must be connected to a common
15
vent with an oil burning furnace, the vent pipe should enter the smaller common vent or chimney at a point above the large vent pipe.

MULTIPLE HEATER MANIFOLD

Figure 13 and Table 7 should be used for horizontally manifolding
two or more heaters.
FIGURE 13

FRESH AIR OPENINGS FOR CONFINED SPACES

The following instructions shall be used to calculate the size, number and placement of openings providing fresh air for combustion, ventilation and dilution in conned spaces. The illustrations shown in this section of the manual are a reference for the openings that provide fresh air into conned spaces only. DO NOT refer to these illustrations for the purpose of vent installation. See Venting Installation on page 15 for complete venting installation instructions.

OUTDOOR AIR THROUGH TWO OPENINGS

OUTDOOR AIR THROUGH ONE OPENING

FIGURE 15
Alternatively a single permanent opening, commencing within 12 inches (300 mm) of the top of the enclosure, shall be provided. See Figure 15. The water heater shall have clearances of at least 1 inch (25 mm) from the sides and back and 6 inches (l50 mm) from the front of the appliance. The opening shall directly communicate with the outdoors or shall communicate through a vertical or horizontal duct to the outdoors or spaces that freely communicate with the outdoors and shall have a minimum free area of the following:
1. 1 square inch per 3000 Btu/hr (733 mm2 per kW) of the total input rating of all appliances located in the enclosure, and
2. Not less than the sum of the areas of all vent connectors in the space.

OUTDOOR AIR THROUGH TWO HORIZONTAL DUCTS

FIGURE 14
The conned space shall be provided with two permanent openings, one commencing within 12 inches (300 mm) of the top and one commencing within 12 inches (300 mm) of the bottom of the enclosure. The openings shall communicate directly with the outdoors. See Figure 14.
Each opening shall have a minimum free area of 1 square inch per 4,000 Btu/hr (550 mm2 per kW) of the aggregate input rating of all appliances installed in the enclosure. Each opening shall not be less than 100 square inches (645 cm2).
FIGURE 16
The conned space shall be provided with two permanent horizontal ducts, one commencing within 12 inches (300 mm) of the top and one commencing within 12 inches (300 mm) of the bottom of the enclosure. The horizontal ducts shall communicate directly with the outdoors. See Figure 16.
Each duct opening shall have a minimum free area of 1 square inch per 2,000 Btu/hr (1100 mm2 per kW) of the aggregate input rating of all appliances installed in the enclosure.
When ducts are used, they shall be of the same cross sectional area as the free area of the openings to which they connect. The minimum dimension of rectangular air ducts shall be not less than 3 inches.
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