A.O. Smith BTF-75 User Manual
MODEL BTF-75 with Hot Surface Ignition & SmartV alve
COMMERCIAL GAS, GLASS-LINED, T ANK-TYPE WA TER HEA TER
• SAFETY • INST ALLATION • OPERATION • MAINTENANCE • LIMITED WARRANTY
Thank you for buying this energy efficient water heater from A.O. Smith
Water Products Company. We appreciate your confidence in our
products.
®
CAUTION
TEXT PRINTED OR OUTLINED IN RED CONTAINS
INFORMATION RELA TIVE TO YOUR SAFETY .
THOROUGHLY BEFORE INST ALLING AND USING THIS
APPLIANCE.
A DIVISION OF A.O. SMITH CORPORATION
McBee, South Carolina U.S.A.
Stratford, Ontario Canada
® SmartValve is a Registered Trademark of Honeywell Inc.
KEEP THIS MANUAL IN THE POCKET ON THE HEATER FOR FUTURE REFERENCE
WHENEVER MAINTENANCE ADJUSTMENT OR SERVICE IS REQUIRED.
PRINTED IN U.S.A. 0901 PART NO. 194643-000
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www.hotwater.com
PLEASE READ
ROUGH-IN-DIMENSIONS
TOP VIEW
*INST ALL IN ACCORDANCE WITH LOCAL CODES
FIGURE 1
ALL DIMENSIONS IN INCHES
Model Units A B C D E F G H J K L M
BTF-75 Inches 66 5/16 58 1/2 29 5/8 25 3/8 15 3/16 4 14 16 1 1/4 1 1/2 11 15/16
cm 168.4 148.6 75.2 64.5 38.6 10.2 35.6 40.6 3.2 NPT NPT 30.3
RECOVERY CAP ACITIES
Input Approx. Approx. Temp. °C 17 22 28 33 39 44 50 56 61 67 72 78
Model Rating Rating Gal. Liter
Btu/Hr KW/Hr Cap. Cap. Rise ° F 30 40 50 60 70 80 90 100 110 120 130 140
BTF-75 80,000 23.4 74 284 LPH 979 734 587 489 419 367 326 294 267 245 226 210
GPH 259 194 155 129 111 97 86 78 71 65 60 55
Recovery capacity based on 80% thermal efficiency.
FOREWORD
The design of model BTF-75 complies with the latest version of
ANSI Z21.10.3/CSA 4.3 M98 as automatic storage or automatic circulating
tank type water heaters.
Installation diagrams are found in this manual. These diagrams will serve
to provide the installer with a reference for the materials and method of
piping necessary. It is highly essential that all water and gas piping be
installed as shown on the diagrams.
In addition to these instructions, the equipment shall be installed in
accordance with those installation regulations in force in the local area
where the installation is to be made. These shall be carefully followed
in all cases. Authorities having jurisdiction should be consulted before
installations are made.
The installation must conform to these instructions and the local code
authority having jurisdiction. In the absence of local codes, the installation
must comply with the latest editions of the National Fuel Gas Code,
ANSI Z223.1/NFPA 54. The NFP A. This is available from the Canadian
Standards Association, 8501 East Pleasant V alley Road, Cleveland, OH
44131, or the National Fire Protection Association, 1 Batterymarch Park,
Quincy, MA 02269.
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TABLE OF CONTENTS
PAGE
ROUGH-IN DIMENSIONS ..............................................................2
FOREWORD ...............................................................................2
GENERAL SAFETY INFORMATION
Precautions ............................................................................ 3
Chemical Vapor Corrosion ......................................................3
Improper Combustion ..............................................................3
Liquid Petroleum Models........................................................ 3-4
Extended Non-Use periods ..................................................... 4
Insulation Blankets ..................................................................4
Circulating Pump .....................................................................4
Dishwashing Machine Requirements ......................................4
INST ALLATION
Required Ability ......................................................................4
General .................................................................................. 4
Grounding ..............................................................................4
High Altitude Installation ..........................................................4
Location Of Heater ...............................................................4-5
Air Requirements ....................................................................5
Unconfined Space ..................................................................5
Confined Space...................................................................... 5
Water Connections .................................................................5
Water (Potable) Heating & Space Heating ............................. 5-6
Closed Water System .............................................................6
Relief Valve............................................................................6
Venting...................................................................................6
Vent Pipe T ermination............................................................ 6-7
Planning The Vent System .................................................... 7-8
P AGE
Installation Of Sidewall Vent System.......................................7
Vent T erminal Installation, Sidewall..........................................7
Preparation Of Blower Assembly ......................................... 8-9
Installation Of Vent System, Sidewall.....................................10
Installation Of Vertical V ent System ....................................... 10
Vent Pipe Preparation ......................................................... 10-12
Gas Connections ...................................................................12
Connection of Gas Pipe ......................................................... 12
OPERATION
T o Operate Heater .................................................................1 2
Lighting & Operating Label .....................................................13
Purging ..................................................................................14
T emperature Regulation .........................................................1 4
MAINTENANCE
Main Burner ...........................................................................14
High T emperature Cut-Off Switch .......................................... 15
Venting System .....................................................................15
Power Venter Maintenance ................................................... 15
T & P V alve............................................................................15
Draining................................................................................. 15
Main Burner And Igniter ...................................................... 15-16
Condensation ........................................................................ 16
Cathodic Protection - Anode .................................................. 16
Service & Repair ...................................................................16
TROUBLE SHOOTING ............................................................. 16-19
LIMITED WARRANTY .................................................................20
GENERAL SAFETY INFORMATION
PRECAUTIONS
DO NOT USE THIS APPLIANCE IF ANY P ART HAS BEEN UNDER WA TER.
Immediately call a qualified service technician to inspect the appliance
and to replace any part of the control system and any gas control which
has been under water.
IF THE UNIT IS EXPOSED TO THE FOLLOWING, DO NOT OPERA TE HEATER
UNTIL ALL CORRECTIVE STEPS HAVE BEEN MADE BY A QUALIFIED
SERVICEMAN.
1. EXTERNAL FIRE.
2. DAMAGE.
3. FIRING WITHOUT WA TER.
4. SOOTING.
CHEMICAL VAPOR CORROSION
WARNING
CORROSION OF THE FLUEWA YS AND VENT SYSTEM MAY OCCUR IF
AIR FOR COMBUSTION CONT AINS CERTAIN CHEMICAL V APORS. SUCH
CORROSION MA Y RESULT IN F AILURE AND RISK OF ASPHYXIATION.
Spray can propellants, cleaning solvents, refrigerator and air conditioning
refrigerants, swimming pool chemicals, calcium and sodium chloride
(water softener salt), waxes, and process chemicals are typical
compounds which are potentially corrosive.
Do not store products of this sort near the heater. Also, air which is
brought in contact with the heater should not contain any of these
chemicals. If necessary , uncontaminated air should be obtained from
remote or outside sources. The limited warranty is voided when failure
of water heater is due to a corrosive atmosphere. (Refer to the limited
warranty for complete terms and conditions).
IMPROPER COMBUSTION
WARNING
A TTIC AND/OR EXHAUST FANS OPERA TING ON THE PREMISES WITH A
WA TER HEATER CAN RESUL T IN CARBON MONOXIDE POISONING AND
DEA TH.
OPERATION OF THESE F ANS CAN PRODUCE A NEGA TIVE DRAFT IN
THE AREA OF THE WA TER HEATER PREVENTING THE PRODUCTS OF
COMBUSTION FROM EXHAUSTING THROUGH THE VENT PIPE.
The venting of the water heater should be inspected by a qualified service
technician at the time of installation and periodically thereafter to ensure
a down-draft condition does not exist.
DO NOT OBSTRUCT THE FLOW OF COMBUSTION AND VENTILA TING
AIR. ADEQUATE AIR FOR COMBUSTION AND VENTILA TION MUST BE
PROVIDED FOR SAFE OPERA TION.
LIQUID PETROLEUM MODELS
WARNING
Water heaters for propane or liquefied petroleum gas (LPG) are dif ferent
from natural gas models. A natural gas heater will not function safely
on LP gas and no attempt should be made to convert a heater from
natural gas to LP gas.
LP gas must be used with great caution. It is highly explosive and heavier
than air. It collects first in the low areas making its odor dif ficult to detect
at nose level. If LP gas is present or even suspected, do not attempt to
find the cause yourself. Go to a neighbor's house, leaving your doors
open to ventilate the house, then call your gas supplier or service agent.
Keep area clear until a service call has been made.
At times you may not be able to smell an LP gas leak. One cause is odor
fade, which is a loss of the chemical odorant that gives LP gas its
distinctive smell. Another cause can be your physical condition, such
as having a cold or a diminishing sense of smell with age. For these
reasons, the use of a propane gas detector is recommended.
3
IF YOU EXPERIENCE AN OUT-OF-GAS SITUA TION, DO NOT TRY TO
RELIGHT APPLIANCES YOURSELF . Ask your LP delivery person to relight
pilots for you. Only trained LP professionals should conduct the required
safety checks in accordance with industry standards.
EXTENDED NON-USE PERIODS
WARNING
HYDROGEN GAS CAN BE PRODUCED IN A HOT WA TER SYSTEM
SERVED BY THIS HEA TER THAT HAS NOT BEEN USED FOR A LONG
PERIOD OF TIME (GENERALLY TWO WEEKS OR MORE).
GAS IS EXTREMELY FLAMMABLE. To reduce the risk of injury under
these conditions, it is recommended that the hot water faucet be opened
for several minutes at the kitchen sink 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 flow. THERE SHOULD BE NO SMOKING
OR OPEN FLAME NEAR THE FAUCET A T THE TIME IT IS OPEN.
HYDROGEN
INSULATION BLANKETS
All dishwashing machines meeting the National Sanitation Foundation
requirements are designed to operate with water flow pressures
between 15 and 25 psi (103Kpa and 173 Kpa). Flow pressures above
25 psi (173Kpa), or below 15 psi (103 Kpa), will result in improperly
sanitized dishes. Where pressures are high, a water pressure reducing
or flow regulating control valve should be used in 180
dishwashing machine, and should be adjusted to deliver water between
these limits.
The National Sanitation Foundation also recommends circulation of 180
(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
water at the point of take-off to the dishwashing machine. Adjust flow
by means of the plug cock in the circulating line.
0
F line to the
0
F (82°C)
INSTALLATION
REQUIRED ABILITY
0
F
Insulation blankets available to the general public for external use on
gas water heaters are not necessary with A.O. Smith products. The
purpose of an insulation blanket is to reduce the standby heat loss
encountered with storage tank heaters. Y our A.O. Smith water heater
meets and exceeds the National Appliance Energy Conservation Act
standards with respect to insulation and standby loss requirements,
making an insulation blanket unnecessary.
WARNING
Should you choose to apply an insulation blanket to this heater, you
should follow these instructions. Failure to follow these instructions
can restrict the air flow required for proper combustion, potentially
resulting in fire, asphyxiation, serious personal injury or death.
Do not cover the gas valve or temperature & pressure relief valve.
•
Do not allow insulation to come within 2" of the air inlet box, to prevent
•
blockage of the dilution air.
Do not allow insulation to come within 2" of the floor to prevent
•
blockage of combustion air flow to the burner.
•
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 A.O. Smith 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 flow.
CIRCULATING PUMP
A circulating pump is used when a system requires a circulating loop or
there is a storage tank used in conjunction with the heater. Refer to the
piping diagrams at rear of manual for electrical hookup information and
install in accordance with the latest version of the
ANSI/NFPA No. 70.
Only all bronze circulators are used with commercial water heaters.
Although circulators are oiled and operated by the manufacturer some
circulators must be oiled again before operating. Please refer to
manufacturer’s instructions.
National Electric Code
DISHWASHING MACHINE REQUIREMENT
These appliances meet the National Sanitation Foundation Standard for
sanitary installations when used with the following leg kits, Part No’s.
6570-0 and 6570-7.
INSTALLA TION OR SERVICE OF THIS WA TER HEA TER REQUIRES ABILITY
EQUIV ALENT TO THA T OF A LICENSED TRADESMAN IN THE FIELD
INVOL VED. PLUMBING, ELECTRICAL AIR SUPPLY , VENTING AND GAS
SUPPL Y ARE REQUIRED.
GENERAL
The heater is designed to operate on natural or propane gases.
HOWEVER, MAKE SURE the gas on which the heater will operate is the
same as that specified on the heater model and rating plate. The
installation must conform to these instructions and the local code authority
having jurisdiction. In the absence of local codes, conform to the latest
edition of National Fuel Gas Code ANSI Z223.1/NFP A 54 and the National
Electric Code, NFPA 70. The former is available from the Canadian
Standards Association, 8501 East Pleasant V alley Road, Cleveland, OH
44131, and both documents are available from the National Fire Protection
Association, 1 Batterymarch Park, Quincy, MA 02269.
GROUNDING
The water heater, when installed, must be grounded in accordance with
local codes, or in the absence of local codes: The National Electric
Code, ANSI/NFPA 70;
HIGH ALTITUDE INSTALLATION
CAUTION
INST ALLATIONS ABOVE 2000 FT. REQUIRE REPLACEMENT OF THE
BURNER ORIFICE IN ACCORDANCE WITH THE NA TIONAL FUEL GAS
CODE (ANSI Z223.1/NFPA 54). F AILURE TO REPLACE THE ORIFICE
COULD RESUL T IN IMPROPER AND INEFFICIENT OPERATION OF THE
APPLIANCE, PRODUCING CARBON MONOXIDE GAS IN EXCESS OF SAFE
LIMITS, WHICH COULD RESULT IN SERIOUS PERSONAL INJUR Y OR
DEA TH. CONTACT YOUR GAS SUPPLIER FOR ANY SPECIFIC CHANGES
WHICH MA Y BE REQUIRED IN YOUR AREA.
A.O. SMITH BUILDS SOME MODELS SPECIFICALLY FOR HIGH AL TITUDE
SERVICE.
PLEASE CHECK THE RATING PLA TE BEFORE MAKING CHANGES.
LOCATION OF HEATER
When installing the heater, consideration must be given to proper location.
Location selected should be as close to the wall as practicable with
adequate air supply and as centralized with the water piping system as
possible.
4
The heater is design certified by the Canadian Standards for installation
on combustible flooring in a closet having minimum clearances from
combustible material of: 2" clearance from sides and rear, 6" from the
front and 24" from the top. (Standard clearance.) If clearances stated
on the heater differ from standard clearances, install water heater
according to clearances stated on heater.
A minimum clearance of 4" must be allowed for access to replaceable
parts such as the thermostats, drain valve and relief valve. A top
clearance of 24" should be allowed for blower assembly service.
Adequate clearance for servicing this appliance should be considered
before installation, such as changing the anodes, etc. Minimum
clearances for proper operation are given above.
WARNING
In cold climates provide protection against freeze-up.
THE HEA TER SHOULD BE LOCATED IN AN AREA WHERE LEAKAGE OF
THE TANK OR CONNECTIONS WILL NOT RESUL T IN DAMAGE TO THE
AREA ADJACENT TO THE HEA TER OR TO LOWER FLOORS OF THE
STRUCTURE. When such locations cannot be avoided, a suitable drain
pan should be installed under the heater, see fig. 1. The pan must not
restrict combustion air flow. Such pans should have a minimum length
and width of at least 2 inches greater than the diameter of the heater
and should be piped to an adequate drain. Drain pans suitable for these
heaters are available from your dealer or A. O. Smith Water Products
Company, 5621 W . 1 15th Street, Alsip, Illinois 60803.
If the confined space is within a building of tight construction, air for
combustion, ventilation and power venter dilution must be obtained from
outdoors. When directly communicating with the outdoors or
communicating through vertical ducts, two permanent openings, located
in the above manner, shall be provided. Each opening shall have a free
area of not less than one square inch per 4000 Btuh of the total input of
all appliances in the enclosure. If horizontal ducts are used, each opening
shall have a free area of not less than one square inch per 2000 Btuh of
the total input of all appliances in the enclosure.
WARNING
DO NOT INST ALL THIS WA TER HEATER DIRECTL Y ON A CARPETED
FLOOR. A FIRE HAZARD MA Y RESUL T . 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 (76.2mm) in any direction. If the heater is
installed in a carpeted alcove or closet, the entire floor shall be covered
by the panel.
AIR REQUIREMENTS
In calculating the free area of a vent opening, the blocking effect of
screens, louvers and grills should be considered. Screens shall not be
of a mesh smaller than 1/4 inch square. If the free area is not known,
the latest edition of National Fuel Gas Code ANSI Z223.1 recommends
using figures of 20-25 percent free area for wood louvers or 60-75
percent for metal grills or louvers.
UNCONFINED SPACE
In buildings of conventional frame, brick or stone construction, unconfined
spaces may provide adequate air for combustion, ventilation, and dilution
air for power venter.
If the unconfined space is within a building of tight construction (building
using the following construction: weather stripping, heavy insulation,
caulking, vapor barrier, etc.), air for combustion, ventilation, and venter
dilution must be obtained from outdoors. The installation instructions for
confined spaces must be followed.
CONFINED SPACE
When drawing combustion and dilution air from inside a conventionally
constructed building to a confined space, such a space shall be provided
with two permanent openings. ONE WITHIN 12 INCHES OF THE
ENCLOSURE TOP AND ONE WITHIN 12 INCHES OF THE ENCLOSURE
BOTTOM. Each opening shall have a free area of one square inch per
1000 Btuh of the total input of all appliances in the enclosure, but not
less than 100 square inches.
WATER CONNECTIONS
Refer to figure 12 for typical installation. A suitable pipe thread sealant
must be used to prevent leakage.
WATER (POTABLE) HEATING AND SP ACE
HEATING
1. All piping components connected to this unit for space heating
applications shall be suitable for use with potable water.
2. T oxic chemicals, such as those used for boiler treatment, shall NEVER
be introduced into this system.
3. This unit may NEVER be connected to any existing heating system or
component(s) previously used with a non-potable water heating
appliance.
4. When the system requires water for space heating at temperatures
higher than required for domestic water purposes, a tempering valve
must be installed. Please refer to Fig. 2 for suggested piping
arrangement.
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SINGLE TEMPERA TURE
MIXING V AL VE APPLICATION FOR TWO TEMPERATURE W ATER
WARNING
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATURE A T FIXTURES. SEE TEMPERATURE REGULATION
ON PAGE 9. IF HIGHER PREHEAT TEMPERATURES ARE
NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN
ANTI-SCALD VALVE FOR HOT WA TER SUPPLIED T O FIXTURES.
CIRCULATING RETURN LINE CONNECTIONS
TEMPERED WATER LOOP, IF USED, CONNECT TO POINT "A". STORED
TEMPERATURE W ATER LOOP, IF USED, CONNECT TO COLD WATER INLET
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACK-FLOW
PREVENTER, CHECK VA LVE OR WATER METER WITH CHECK VALVE,
PROVISIONS FOR THERMAL EXPANSION OF W ATER IN THE HOT WATER
SYSTEM MUST BE PROVIDED.
FIGURE 2
CLOSED WATER SYSTEM
A closed system will exist if a back-flow preventer (check valve),
pressure reducing valve, or other similar device is installed in the cold
water line between the water heater and the street main (or well).
Excessive pressure may develop due to the thermal expansion of heated
water causing premature tank failure or intermittent relief valve operation.
This type of failure is not covered by the limited warranty. An expansion
tank may be necessary in the cold water supply to alleviate this situation.
Contact the local plumbing authority.
If the temperature and pressure relief valve on the appliance discharges
periodically, this may be due to thermal expansion in a closed water
supply system. Contact the water supplier or local plumbing inspector
on how to correct situation. DO NOT PLUG THE TEMPERA TURE AND
PRESSURE RELIEF VAL VE.
RELIEF V AL VE
A NEW TEMPERATURE AND PRESSURE RELIEF V ALVE COMPL YING WITH
THE ST ANDARD FOR RELIEF VAL VES AND AUTOMATIC GAS SHUT OFF
DEVICES FOR HOT WA TER SUPPLY SYSTEMS, ANSI Z21.22 (LA TEST
EDITION) MUST BE INSTALLED IN THE HEA TER IN THE MARKED OPENING
PROVIDED. THE VAL VE MUST BE OF A SIZE (INPUT RA TING) THA T
WILL BE ADEQUATE FOR YOUR SIZE HEA TER.
Check the metal tag on the relief valve and compare it to the heater’s
rating plate. The pressure rating of relief valve must not exceed the
working pressure shown on the rating plate of the heater. In addition
the hourly Btu rated temperature steam discharge capacity of the relief
valve shall not be less than the input rating of the heater. NO V AL VE IS
TO BE PLACED BETWEEN THE RELIEF VAL VE AND T ANK. DO NOT PLUG
THE RELIEF VAL VE.
VENTING
WARNING
THE INSTRUCTIONS IN THIS SECTION ON VENTING MUST BE FOLLOWED
TO A VOID CHOKED COMBUSTION OR RECIRCULATION OF FLUE GASES.
SUCH CONDITIONS CAUSE SOOTING OR RISKS OF FIRE AND
ASPHYXIATION. NEVER OPERA TE THE HEATER UNLESS IT IS VENTED
TO THE OUTDOORS AND HAS ADEQUA TE AIR SUPPLY TO A VOID RISKS
OF IMPROPER OPERATION, FIRE, EXPLOSION OR ASPHYXIA TION.
VENT PIPE TERMINATION
The first step is to determine where the vent pipe will terminate. The
vent may terminate through the roof (see Figure 9) or through a sidewall
(see Figure 8).
IMPORTANT
The vent system must terminate so that proper clearances are maintained
as cited in local codes or the latest edition of the National Fuel Gas Code,
ANSI Z223.1, 7.3.4e and 7.8a, b.
For your convenience instructions on proper installation through a
sidewall are provide in Figure 3 and the numbered points below:
1. The exit terminals of a mechanical vent system shall be not less than
7 feet above grade when located adjacent to public walkways.
2. A venting system shall terminate at least 3 feet above any forced air
inlet located within 10 feet.
3. The venting system shall terminate at least 4 feet below, 4 feet
horizontally from or, 1 foot above any door, window or gravity air
inlet into any building.
The drain line connected to this valve must not contain a reducing coupling
or other restriction and must terminate near a suitable drain to prevent
water damage during valve operation. The discharge line shall be installed
in a manner to allow complete drainage of both the valve and line. DO
NOT THREAD, PLUG OR CAP THE END OF THE DRAIN LINE.
4. The manufacturer also recommends that the vent system termination
not be installed closer than 3 feet from an inside corner of an L shaped
structure and not be less than 1 foot above grade. The vent shall
terminate a minimum of 12'' above expected snowfall level to prevent
blockage of vent termination.
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