A.O. Smith COF-199 User Manual
MODELS COF-199 THRU 700A
COMMERCIAL OIL FIRED WA TER HEATER FOR HOT WA TER SUPPLY
• Installation • Service • Maintenance
ASME
CAUTION
TEXT PRINTED OR OUTLINED IN RED CONT AINS INFORMATION RELA TIVE
TO YOUR SAFETY. PLEASE READ THOROUGHLY BEFORE USING
APPLIANCE.
A DIVISION OF A.O. SMITH CORPORATION
MCBEE, SC • SEA TTLE, WA
STRATFORD, (ONT ARIO) CANADA
VELDHOVEN, THE NETHERLANDS
PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND
PRINTED IN U.S.A. 0705 PART NO. 193472-001
NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.
1
FEA TURES AND SPECIFICATIONS
TEXT PRINTED OR OUTLINED IN RED CONTAINS INFORMATION
RELA TIVE TO YOUR SAFETY . PLEASE READ THOROUGHLY BEFORE
USING APPLIANCE.
This is a typical Duraclad oil-fired heater for commercial water heating
applications. The principal components of the heater are shown and
identified here. The identification plate illustrations on page 4 interpret
certain markings into useful information. Use these references to identify
the heater and its components
FIGURE 1
TABLE 1 NOMINAL MODEL DIMENSIONS
Model
Dim. Inches mm Inches mm Inches mm Inches mm Inches mm Inches mm
A 74 1/2 1,892 74 1/2 1,892 74 1/2 1,892 73 3/4 1,873 73 3/4 1,873 73 3/4 1,873
B 36 3/4 933 36 3/4 933 36 3/4 9 33 36 3/4 933 36 3/4 933 36 3/4 933
C 27 3/4 705 27 3/4 705 27 3/4 7 05 27 3/4 705 27 3/4 705 27 3/4 705
D 2 51 2 51 2 51 2 51 2 51 2 51
E 3/4 NPT 3/4 NPT 3/4 NPT 3/4 NPT 3/4 NPT 3/4 NPT
F 8 203 8 203 8 203 8 203 8 203 10 254
G 26 5/8 676 26 5/8 676 26 5/8 6 76 24 3/4 629 24 3/4 629 30 3/16 767
H 74 1/2 1,892 74 1/2 1,892 74 1/2 1,892 73 3/4 1,873 73 3/4 1,873 79 3/16 2,011
J 1 1/2 NPT 1 1/2 NPT 1 1/2 NPT 1 1/2 NPT 1 1/2 NPT 1 1/2 NPT
K 1 1/2 NPT 1 1/2 NPT 1 1/2 NPT 1 1/2 NPT 1 1/2 NPT 1 1/2 NPT
L 22 3/4 578 22 3/4 578 22 3/4 578 23 7/16 595 23 7/16 595 28 7/8 733
Approx.
Shipping 553 251 554 252 554 252 624 283 700 318 739 335
Weight STD. Lbs Kg. Lbs. Kg. Lbs. Kg. Lbs. Kg. Lbs. Kg. Lbs. Kg.
Approx.
Shipping 657 298 742 337 747 339 822 373
Weight ASME --- --- --- --- Lbs. Kg. Lbs. Kg. Lbs. Kg. Lbs. Kg.
ALL DIMENSIONS IN INCHES/mm
*Model numbers followed by the suffix "A" indicates the optional A.S.M.E. tank construction.
COF - 199 COF - 245 COF - 315/315A COF - 385/385A COF - 455/455A COF - 700/700A
T ABLE 2 RECOVERY CAPACITIES, based on 80% efficiency
TANK APPROX U.S Gallons/Hr. and Litres/Hr at TEMPERATURE RISE INDICATED
Model Btuh KW U.S.Gal. Litres % C° 22.2C° 27.7C° 33.3C° 38.8C° 44.4C° 50C° 55.5C° 61.1C° 66.6C° 72.2C° 77.7C°
COF 199,000 86 80 GPH 477 381 318 272 238 212 191 173 159 147 136
199 58 326 LPH 1804 1443 1203 1031 902 802 722 656 601 555 516
COF 245,000 86 80 GPH 587 469 391 335 293 261 235 213 196 181 168
245 72 326 LPH 2221 1777 1481 1269 1111 987 889 808 740 683 635
COF 315,000 84 80 GPH 754 604 503 431 377 335 302 274 251 232 216
315/315A 92 318 LPH 2856 2285 1904 1632 1428 1269 1142 1039 952 879 816
COF 385,000 75 80 GPH 922 738 615 527 461 410 369 335 307 284 263
385/385A 113 284 LPH 3491 2793 2327 1995 1745 1551 1396 1269 1164 1074 997
COF 455,000 75 80 GPH 1090 872 727 623 545 484 436 396 363 335 311
455/455A 133 284 LPH 4125 3300 2750 2357 2063 1833 1650 1500 1375 1269 1179
COF 700,000 69 80 GPH 1677 1341 1118 958 838 745 671 610 559 516 479
700/700A 205 261 LPH 6347 5077 4231 3627 3173 2821 2539 2308 2116 1953 1813
* All tanks are tested at 320 psig working pressure.
** Based on No. 2 fuel oil with a heat content of 140,000 Btu's per gallon at 80% thermal efficiency. Above 2,000 altitude, input
ratings should be reduced 4% for each 1000' above sea level.
CAPACITY EFF. F° 40F° 50F° 60F° 70F° 80F° 90F° 100F° 110F° 120F° 130F° 140F°
2
TABLE OF CONTENTS
FEATURES AND SPECIFICATIONS........................................... 2
APPROVALS ............................................................................... 3
IDENTIFICATION
Oil and Burner Nameplate Decal ....................................... 3
Oil Burner Specifications.................................................... 4
SAFETY ....................................................................................... 4
INSTALLATION
Required Ability .................................................................. 4
General............................................................................... 4
Uncrating ............................................................................ 4
Leveling .............................................................................. 4
Location.............................................................................. 4-5
Clearances ......................................................................... 5
Combustion and Ventilation Air .......................................... 5
Chemical Vapor Corrosion ................................................. 5-6
Flue Gas Venting................................................................ 6
Vent Connector and Draft Regulator .................................. 6
Water Piping ....................................................................... 7
Closed Water System ........................................................ 7
Drain Valve and Access Panels .........................................7
Fuel Systems ..................................................................... 7-8
Burner Installation .............................................................. 8-9
Fuel Pump .......................................................................... 9
Wiring Diagrams ................................................................. 10
OPERATION
General............................................................................... 11
Filling .................................................................................. 11
Start Up .............................................................................. 11
APPROVALS
The burner and controls are listed by Underwriters' Laboratories Inc.
Accordingly, the burner bears one of the UL labels indicating periodic
inspection of the production of this equipment.
Water Temperature Control ................................................ 11
High Limit Switch E.C.O. .................................................... 11-12
Burner Certificate (Combustion Test) ............................... 12
Self-Cleaning Eliminator ..................................................12
Draining ............................................................................. 12
MAINTENANCE
General............................................................................... 12
Relief Valves ...................................................................... 12
Flushing .............................................................................. 13
Sediment Removal ............................................................. 13
Lime Scale Removal .......................................................... 13-14
Circulating Pump ................................................................ 14
Soot Removal ..................................................................... 14
Vent System ....................................................................... 14
INSTALLATION DIAGRAMS ....................................................... 15-19
CHECKLIST AND SERVICE INFORMATION
Electrical Wiring Replacement ........................................... 20
Not Enough or No Hot Water ............................................. 20-21
Burner Starts - Won't Operate ............................................ 21
Water Too Hot .................................................................... 21
Water Heater Makes Sounds............................................. 21
Water Leakage is Suspected ............................................. 21
Burner Won't Start .............................................................. 21
Burner Starts But Fails To Run ........................................... 21
Normal Start, But Locks Out On Safety ............................. 22
Safety Primary Control ....................................................... 22
COMBUSTION TEST SPECIFICATIONS .................................... 22
TROUBLESHOOTING ................................................................. 23
WARRANTY................................................................................. 24
All ASME tanks are built to the standards of Section IV of the American
Society of Mechanical Engineers code and are stamped with their symbol.
The National Board of Boiler and Pressure Vessel Inspectors papers are
furnished upon request. The NB number and HLW symbol (to the right)
are on the plate located just below cleanout on tank. (May be viewed by
removing cleanout cover on jacket).
IDENTIFICATION
The heater and burner rating plates or labels provide valuable information.
When ordering parts or inquiring about a unit, be sure to include all
information from the plates. See the picture on page 2 for approximate
location of the heater rating plate.
The heater rating plate model number, see fig. 2, includes a series
number which identifies the construction of the heater.
COF 455 940
455,000 3.25
CO5MOO6721
XXX.X XX
XXXXXXXXXX
XXX
OIL BURNER NAMEPLA TE DECAL
The oil burner's nameplate decal (see page 2 for the approximate location
on the burner) contains a burner code 940 or 941 which should exactly match
the model input appearing under the model number of the heater's rating plate.
If these codes do not match, the oil burner may not be the correct model for
the heater model purchased, Contact your A.O. Smith dealer for further
information and replacement, if required.
120
10
60
A TYPICAL HEA TER RATING PLATE
FIGURE 2
A TYPICAL OIL BURNER NAMEPLATE DECAL
FIGURE 3
3
OIL BURNER SPECIFICA TIONS
The oil burner nameplate decal includes a series code which identifies
the major features of the oil burner. The series number is the last three
digits of the burner code number.
Table 3 below describes the oil burner characteristics for each series
number. The burners are to be used with fuel oil not heavier than No. 2.
If it is necessary to reset the safety control, depress red button one time
only . If burner does not operate after depressing red button one time, call
serviceman.
INSTALLA TION
REQUIRED ABILITY
TABLE 3 SOME NOTABLE OIL BURNER FEATURES
A.O. Smith R.W. Suntec Nozzle Type
Burner Becket Safety Oil Pump Oil
or Heater Burner Timing Type Pump
Series Model + Mode Spray Spray
Number* Number Pattern Angle
A2VA
AFG 71 18 Type B
940 15 Sec. Single - Solid 80°
SF Stage A2YA- Cone
7916
B2VA
8216 Type B
941 AFG 15 Sec. Two- - Solid 80°
SF 15 Sec. Stage BY2A Cone
8916
* To provide the proper firing rate for each model heater, see SPECIFICA TIONS:
there are burner models for each heater model in table 2. The Burner and heater
model numbers must match and the heater (or the burner) series number should
indicate the features specified for the installation.
+ All oil burners are UL defined as having "interrupted ignition" . . . meaning the
ignition is on during the flame establishing period only . Ignition is of f when the
burner is off. S tandard safety timing is 15 seconds.
The heater series number determines the type of oil pump supplied
with the oil burner. For installations where gravity feed of fuel oil from
the storage tank to the heater is practical, an oil burner with a singlestage oil pump can be used. The 940 series of burners have singlestage pumps which are shipped for installation of a supply line to the
tank only. A return line back to the storage tank can be installed, if
required, by making a small modification to the pump, see the oil burner
installation manual.
For installations where gravity feed cannot be employed, (the storage
tank is located significantly below , or remote from, the heater) an oil burner
with a two-stage oil pump should be used. The 941 series of burners
have two-stage pumps which are shipped for installation of a supply and
return line to the tank. However, in situations where the return line is not
required (low lift installations), the pump may be modified to operate without
the line, see the oil burner installation manual.
IMPORTANT
The oil-fired water heater shipment consists of two packages, heater
and oil burner. Check to be certain the model number on the heater and
oil burner packages match. T o assure matching equipment, see preceding
information.
INSTALLA TION OF SERVICE OF THIS W ATER HEA TER REQUIRES ABILITY
EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD
INVOLVED. PLUMBING, AIR SUPPLY, VENTING , OIL BURNER AND
ELECTRICAL WORK REQUIRED.
GENERAL
The installer should be guided by these instructions, local codes and the
following publications.
• Standard for the Installation of Oil Burning Equipment, NFPA
Standard No. 31, Available from National Fire Protection
Association, Batterymarch Park, MA 02269.
• Code for the Installation of Heat Producing Appliances,
Available from American Insurance Association, 85 John Street,
New York, NY 10038.
• The National Electrical Code, NFPA No. 70. Availability
same as NFPA Standard No. 31.
• In Canada - CAN/CSA-B139 Installation Code for Oil Burning Equipment.
When other than an A.O. Smith burner is used, this instruction manual can
be used as a general guide. The burner manufacturer's instructions will
have to be consulted on specific questions of wiring, air adjustment, etc.
Do not test the burner or control system before the heater is filled with
water. Follow the START-UP procedure in this manual.
UNCRA TING
Uncrate the heater by removing the outside mat and top locator. The shipping
pallet must be removed from the unit. It may be possible to simply unbolt the
base from the pallet and, with the help of two or more persons, work the unit
off the pallet. Some units will be too heavy and will require the use of jacks or
lifting equipment. Safely remove the pallet and move the unit into position. Be
Careful When Moving This Heater. It will tip over easily.
LEVELLING
Install the heater plumb to the ground. If it is necessary to adjust the
heater, use metal shims under the channel type skid base.
LOCATION
Model Heater 199 245 315/315A 385/385A 455/455A 700/700/A
COF COF COF COF COF COF
Min. A.O. Smith
Firing Burner 1.42 1.75 2.25 2.75 3.25 5.0
Rate
In Non
GPH A.O. Smith 1.1 1.5 2.0 2.5 3.0 4.5
Burner
SAFETY
DANGER
BE SURE TO TURN OFF POWER WHEN WORKING ON OR NEAR THE
ELECTRICAL SYSTEM OF THE HEA TER. NEVER TOUCH ELECTRICAL
COMPONENTS WITH WET HANDS OF WHEN ST ANDING IN WATER. WHEN
REPLACING FUSES AL WA YS USE THE CORRECT SIZE FOR CIRCUIT .
The water heater should not be installed where the combustion air is
contaminated, see COMBUSTION AND VENTILA TING AIR. T emperature
in the location must be above 32°F (0°C) and free of combustible dusts
and flammable gases or vapors.
For the best installations, the water heater should be located:
1. On a level surface.
• Shim the channel type skid base as necessary If leveling is required.
2. Near a floor drain.
• The heater should be located in an area where leakage of the tank
or connections will not result in damage to the area adjacent to the
heater or to lower floors of the structure.
• When such locations cannot be avoided, a suitable drain pan
should be installed under the heater.
• The pan should be at least two inches deep, have a minimum
length and width of at least two inches greater than the diameter
of the heater and should be piped to an adequate drain. The pan
must not restrict combustion air flow.
4
• The discharge opening of the relief valve should always be piped
to an open drain.
• Choose the point of major hot water usage, fuel supply and chimney.
• Try to make hot water and oil piping as short as possible.
• Insulate hot and cold water piping where heat loss and
condensation may be a problem.
CLEARANCES
The heater has minimum clearances to combustible material, on a noncombustible floor of: 6 inches (152 mm) from the sides and rear, 24
inches (610 mm) from the front, and 18 inches (457 mm) from the vent
connector. These clearances are, as shown in fig. 4A to prevent possible
fire hazard conditions.
At least 24" (610 mm) of top clearances are recommended for vertical
vent installation.
Allow sufficient room at rear of heater for servicing of T&P relief valve.
At least 24" (610 mm) should be provided at the front of the unit for
proper servicing.
Units which are to be installed on combustible flooring must be supported
by a full layer of hollow concrete blocks, fig. 4, from 8" (203 mm) to
12" (305 mm) thick and extending 12" (305 mm) minimum beyond the heater in
all directions. The concrete blocks must provide an unbroken concrete surface
under the heater, with the hollows running continuous and horizontally. A 3 /
16" (4.8 mm) steel plate must cover the concrete blocks, see fig. 3.
CHEMICAL V APOR CORROSION
Water heater corrosion and component failure can be caused by the
heating and breakdown of air borne chemical vapors. Spray can
propellants, cleaning solvents, refrigerator and air conditioning
refrigerants, swimming pool chemicals, calcium and sodium chlorides,
waxes, and process chemicals are typical compounds which are
potentially corrosive. These materials are corrosive at very low
concentration levels with little or no odor to reveal their presence.
Products of this sort should not be stored near the heater. Also, 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 outside sources.
UNCONFINED SP ACES (Building Construction)
NOTE: An uncontaminated space is defined as a space whose volume
is not less than 50 ft3 per 1000 BTUH (4.83m3 per kW)of total input
of all fuel burning appliances installed in that space. The unconfined
space may be thought of as extending to all areas which cannot
be separated by a door or door(s). All other spaces not fitting
this description, should be thought of as confined space.
1. In unconfined spaces in buildings of conventional frame, brick or
stone construction, infiltration will normally supply an adequate
amount of air for combustion and ventilation.
2. If the unconfined space is within a building of tight construction, eg.
weather stripping, heavy insulation, caulking, vapor barrier, ect., air
infiltration may be insufficient to support proper combustion and
ventilation, air shall be obtained from outdoors or from spaces freely
communicating with the outdoors.
• Follow the instructions under Part 2 of Confined Spaces (Room
Construction)
PROPER INSTALLA TION ON COMBUSTIBLE FLOORING
FIGURE 4
NOTE: If electrical conduits run under the floor of the proposed heater
location, insulate the floor as recommended above.
PROPER INSTALLATION CLEARANCES FOR TWO DIFFERENT
VENTING SYSTEMS
FIGURE 4A
* HOT WA TER OUTLET LOCA TION A T FRONT OF HEA TER
• FACTORY FURNISHED HEA TER MANIFOLD KITS (OPTIONAL) ARE
DESIGNED FOR 10" (254 mm) SPACING BETWEEN SIDES OF
ADJACENT UNITS.
COMBUSTION AND VENTILATION AIR
GENERAL
The water heater area should have sufficient air for satisfactory
combustion of oil, and proper venting and of safe ambient temperature.
When a heater is installed in an area where exhaust or ventilating fans
may create unsatisfactory combustion or venting, approved provisions must
be made to overcome the problem, see NFP A S t andard No. 31, Chapter 1.
CONFINED SPACES (Room Construction)
1. All air from inside building (conventionally constructed buildings only):
The confined space shall be provided with two permanent openings,
one within 12" (305 mm) of the ceiling and one within 12" (305 mm) of
the floor, fig. 5.
FIGURE 5
• Each opening shall have a free area of not less than one square
inch per 1,000 Btu per hour (140 square inches per gallon of oil
consumed per hour) of the total input rating of all appliances in the
enclosure, freely communicating with the interior areas having in
turn adequate infiltration from the outside. In all cases, each
opening shall not have a free area of less than 100 square inches.
2. All Air From Outdoors: The confined space shall be provided with
two permanent openings, one in or within 12" of the top of the
enclosure and one in or within 12" of the bottom. The openings shall
communicate directly, or by means of ducts, with outdoors or such
spaces that freely communicate with outdoors.
• If the appliance room is located against an outside wall and the air
openings communicate directly with the outdoors, each opening
shall have a free area of not less than one square inch per 4,000
Btu per hour (35 square inches per gallon of oil consumed per
hour) of the total input rating of all appliances in the enclosure.
5
• When communicating with outdoors by means of vertical ducts,
each opening shall have a free area of not less than one square
inch per 4,000 Btu per hour (551 mm2/kW) (35 square inches
per gallon of oil consumed per hour) of total input rating 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 2,000 Btu per hour
(1,101 mm2/kW) (70 square inches per gallon of oil
consumed per hour) of total input of all appliances in the
enclosure, fig. 6.
T ABLE 4 SUGGESTED VENT CONNECTOR SIZES
Outlet Diameter
Model Number Inches (mm)
COF-199* 6 152.4
COF-245 8 203.2
COF-315/315A 8 203.2
COF-385/385A 8 203.2
COF-455/455A 8 203.2
COF-700/700A 10 254
* These models are factory supplied with a flue reducer which
should be installed on the top cover.
In venting systems where a continuous or intermittent back
(positive) draft is found to exist, the cause must be determined
and corrected. In some cases, a special vent cap may be
required.
If the back draft cannot be corrected by normal methods or if a
suitable draft cannot be obtained, additional make up air must be
provided to the room to assure proper venting and combustion.
Note: A negative draft must be maintained in the vent piping.
The barometric draft regulator must be installed in the same room as
the heater, fig. 6. Locate the regulator as close as possible to the
heater and at least 18" (452 mm) from a combustible ceiling or wall.
A manually operated damper should not be placed in the chimney
connector.
FIGURE 6
FLUE GAS VENTING
In the absence of any local codes, regulations, or vent pipe or chimney
manufacturer's recommendations, for oil fired equipment, follow the
suggestions below for designing and installing a venting system.
For these water heaters, it is recommended that an adequate
chimney be used for venting the flue gases. Type B, double wall,
vent pipe should be used as the vent connector pipe. However,
where no chimney is available, vent pipe may be used to construct
a vent.
Where an existing chimney or vent is to be used, be sure that the
chimney or vent has adequate capacity for the number and
sizes of appliances being vented through it. Inspect the chimney
or vent and remove all soot or other obstructions which will retard
free draft.
VENT CONNECTOR AND DRAFT REGULA TOR
The chimney or vent connector diameter should be the same size as the
heater flue outlet, see Table 4. A minimum rise of 1/4" per foot
(21 mm/M) of horizontal connector length must be maintained between
the heater and chimney opening, fig. 7. The connector length should be
kept as short as possible.
PROPER VENT CONNECTOR INST ALLA TION
FIGURE 7
CHIMNEY
The oil-fired water heater must be connected to a chimney built in
accordance with accepted building code practice or listed factory
built type, Table 5. The exit point of the chimney flue gas must be at
least 3' (0.91M) above the highest point where it passes through
the roof of a building. Also, it must be at least 2' (0.61M) higher than
any portion of a building within 10' (3.05 M) of the chimney.
TABLE 5 - USUAL CHIMNEY SIZES FOR UNITS
Oil Equivalent Output Square & Rectangle
Model Rate Rate Rate Dimension Diameter Height
Number (GPH) (LPH) Btuh kW Btuh kW Inches mm Inches mm Feet Metres
COF-199 1.42 5.38 199,000 58 159,200 47 8 1/2 X 8 1/2 216 x 216 9 228.6 20 6.1
COF-245 1.75 6.62 245,000 72 196,000 57 8 1/2 X 8 1/2 216 x 216 9 228.6 20 6.1
COF-315/315A 2.25 8.52 315,000 92 252,000 74 8 1/2 X 13 216 x 330 10 254 30 9.1
COF-385/385A 2.75 10.41 385,000 113 308,000 90 8 1/2 X 13 216 x 330 10 254 30 9.1
COF-455/455A 3.25 12.30 455,000 133 364,000 107 13 X 13 330 x 330 12 304.8 35 10.7
COF-700/700A 5.0 18.93 700,000 205 560,000 164 13 X 18 330 x 457 14 355.6 40 12.2
Firing Heat Input Heat Stack Round Stack Minimum
6
MULTIPLE HEA TER FLUES
DRAIN V AL VE AND ACCESS P ANELS
When two or more oil-fired water heaters are connected to a single
chimney or vent there shall be sufficient draft available for safe
combustion and removal of combustion products to the outdoors from
each heater. Refer to local codes for connection details.
Only one oil-fired water heater should be connected to any one type L
venting system.
A draft regulator shall be provided for each oil-fired water heater in a
multiple heater system.
DANGER
INCORRECT INST ALLATION CAN CAUSE IMPROPER OPERA TION, FIRE,
ASPHYXIATION, SERIOUS PERSONAL INJURY OR DEATH. NEVER
OPERATE THIS WA TER HEA TER UNLESS IT IS PROPERL Y VENTED TO
THE OUTDOORS AND HAS ADEQUATE COMBUSTION AIR SUPPLY .
WATER PIPING
GENERAL
Select the piping diagram for the type of system to be installed from
pages 15 through 19. When a circulation pump is used in the system a
plug cock should be installed where indicated to regulate water flow through
the heater.
RELIEF VALVE
An CSA design-certified and A.S.M.E.-rated temperature and pressure
relief valve is installed in the water heater . The relief valve has a
discharge capacity exceeding the maximum heater input rating and a
pressure rating not exceeding the working pressure shown on the
rating plate of the heater.
A temperature and pressure relief valve must also be installed on any
potable water storage tank. This relief valve should have a temperature
rating of 210° F (98.8°C), a pressure rating not exceeding the lowest
rated working pressure of any system component, and a discharge
capacity exceeding the total input of the water heaters supplying water to
the storage tank.
THE PURPOSE OF A RELIEF VALVE IS TO AVOID EXCESSIVE
PRESSURE OR TEMPERATURE INTO THE STEAM RANGE, WHICH
MAY CAUSE SCALDING AT FIXTURES, TANK EXPLOSION, SYSTEM
OR HEATER DAMAGE.
To avoid scalding or water damage, a drain line must be connected to a
relief valve to direct discharge to a safe location, A DRAIN LINE MUST
NOT BE REDUCED FROM THE SIZE OF THE VALVE OUTLET AND IT
MUST NOT CONTAIN ANY V AL VES BETWEEN THE HEA TER AND THE
RELIEF VALVE OR THE RELIEF VALVE AND THE DRAIN LINE EXIT.
IN ADDITION, THERE SHOULD NOT BE ANY RESTRICTIONS IN A
DRAIN LINE NOR SHOULD IT BE ROUTED THROUGH AREAS WHERE
FREEZING CONDITIONS MIGHT OCCUR. DO NOT THREAD OR CAP
THE DRAIN LINE EXIT. RESTRICTING OR BLOCKING A DRAIN LINE
WILL DEFEAT THE PURPOSE OF THE RELIEF VALVE AND MAY
CREATE AN UNSAFE CONDITION. Install a drain line with a downward
slope such that it naturally drains itself.
Y our local code authority may have other specific relief valve requirements.
NOTE: These heaters are equipped with an automatic burner shutoff
system actuated by high water temperature.
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, see installation
diagrams on pages 15-19. Contact the local plumbing authority.
The heaters are equipped with a 3/4" NPT drain valve mounted above
and to the left of the oil burner, see FEATURES, page 2.
An access panel is located above and to the left of the oil burner and
covers the flame observation port, fig. 8. A plug is inserted into the flame
observation port and must be removed in order to look into the combustion
chamber. Always reinstall plug before replacing access panel.
COMBUSTION CHAMBER ACCESS PORT - FIGURE 8
Another access panel is located above and to the right of the oil burner,
fig. 9. This panel covers the cleanout opening in the tank which is sealed
by a gasket and cover.
TANK CLEANOUT PORT - FIGURE 9
Models having ASME tank construction will have two cleanout ports. One
port will be located as indicated above and the other will be located directly
opposite.
Occasionally , some water seepage will occur at a cleanout port. T o correct
this situation, slightly tighten the cleanout cover bolts until the seepage is
eliminated. Do not over tighten the bolts or the cleanout gasket will be
damaged. Tighten each bolt gradually and alternate between opposed
bolts on the cleanout cover.
FUEL SYSTEMS
GENERAL
The Standard for the Installation of Oil Burning Equipment-NFPA No. 31,
local codes, and these instructions must be followed when installing the
tank, piping and burner. In addition, an oil pump installation sheet and oil
burner certificate are packed with the burner for use and completion by
the installer.
On fuel systems with high pressures, a Webster "OSV" oil safety valve
(Webster Electric CO., Racine, Wisc.) will be required to reduce the oil
pressure at the burner pump. See FUEL PUMP, page 9, for pressure
ratings of the burner's pump.
This manual and the completed oil burner certificate (CS75) are to be left
with the user for future reference.
Figure 10 shows a typical single stage one or two line fuel system. When
two or more tanks are connected to one burner, the supply line from each
tank should run to a header fitted with an approved three-way valve.
Normally only one tank may be drawn at a time unless local codes permit
simultaneous feeding of two tanks on gravity type installations.
7
A TYPICAL HEA TER INST ALLATION - FIGURE 10
Refer to pages 2, 3, and 4 in this manual for more information about
burner series numbers and characteristics for adaptability to the following
systems.
SYSTEM TYPES
Single Stage, Supply Line Only: The bottom of the oil storage tank must
be above the level of the fuel unit, fig. 11. The fuel oil will flow by gravity
to the burner. A single pipe is run between the tank and fuel unit. Burner
Series No. 940 is from this type of service as shipped (the bypass plug is
not installed).
TABLE 6
Distance Max. Distance Max.
T an k Run length Tank Run Length
Bottom Ft. (M) Bottom Ft. (M)
Below Below
Pump 3/8" 1/2" Pump 3/8" 1/2"
Plug O.D. O.D. Plug O.D. O.D.
Ft. (M) Tubing Tubing Ft. (M) Tubing Tubing
1 (0.3) 66 (20.1) 100 (30.4) 6 (1.8) 36 (10.9) 100 (30.4)
2 (0.6) 55 (16.7) 100 (30.4) 7 (2.1) 31 (9.4) 100 (30.4)
3 (0.9) 50 (15.2) 100 (30.4) 8 (2.4) 26 (7.9) 100 (30.4)
4 (1.2) 45 (13.7) 100 (30.4) 9 (2.7) 21 (6.4) 83 (25.2)
5 (1.5) 40 (12.1) 100 (30.4) 10 (3.0) 16 (4.8) 64 (19.5)
Two Stage, Supply and Return Lines: This system, fig. 13, is required
when long lines and high lifts (requiring up to 20" of vacuum and 10'
vertical lift) are encountered. Burner Series No. 941 is used in this service.
Bypass plug must be installed.
A GRAVITY FEED, SUPPLY LINE ONLY, INSTALLATION
FIGURE 11
If the bottom of the oil tank is at least 2 inches (50.8 mm) higher than the
plug opening at which the supply line connects to the fuel pump, a singleline gravity-feed system with 3/8" O.D. tubing may be used with a maximum
run length of 100 feet.
• A two stage pump may be used on one line, gravity feed
installations. The pump will function as a single stage unit when
the by-pass plug is not installed.
• Single Stage, Supply and Return Lines. This type of system,
fig. 12, is self-priming. Burner Series No. 940 with by-pass plug
field installed, is for this type of service.
If the tank bottom is no lower than 10 feet below the plug, a single stage
pump may be used but, it must be a two line system with maximum
tubing runs (which includes lift) as shown in Table 6.
A TWO STAGE (HIGH LIFT), SUPPLY AND RETURN
LINE INSTALLA TION - FIGURE 13
If the tank(s) bottom is lower than the plug by more than 10 feet, a two
stage pump with a two line system must be used with maximum tubing
runs (which includes lift) as shown in Table 7.
TABLE 7
Distance Max. Distance Max.
T an k Run length Tank Run Length
Bottom Ft. (M) Bottom Ft. (M)
Below Below
Pump 3/8" 1/2" Pump 3/8" 1/2"
Plug O.D. O.D. Plug O.D. O.D.
Ft. (M) Tubing Tubing Ft. (M) Tubing Tubing
1 (0.3) 74 (22.5) 100 (30.4) 9 (2.7) 51 (15.5) 100 (30.4)
2 (0.6) 71 (21.6) 100 (30.4) 10 (3.0) 48 (14.6) 100 (30.4)
3 (0.9) 69 (21.0) 100 (30.4) 11 (3.3) 45 (13.7) 100 (30.4)
4 (1.2) 66 (20.1) 100 (30.4) 12 (3.6) 42 (12.8) 100 (30.4)
5 (1.5) 63 (19.2) 100 (30.4) 13 (3.9) 39 (11.8) 100 (30.4)
6 (1.8) 60 (18.2) 100 (30.4) 14 (4.2) 37 (11.2) 100 (30.4)
7 (2.1) 57 (17.3) 100 (30.4) 15 (4.5) 34 (10.3) 100 (30.4)
8 (2.4) 54 (16.4) 100 (30.4)
MULTIPLE HEATER FUEL LINES
Where two or more heaters form a water heating system, each burner
shall have an entirely separate oil supply line from the tank to the burner .
BURNER INST ALLA TION
A SINGLE STAGE (LOW LIFT), SUPPLY AND RETURN
LINE INST ALLA TION - FIGURE 12
GENERAL
An oil Burner Certificate is packed with the oil burner. Following the burner
manual installation the necessary tests shall be performed and the results
recorded on the certificate, see BURNER CERTIFICATE. The certificate
and this instruction manual must be left with the user for future reference.
Check to be certain the heater and burner model numbers are alike and
the oil pump characteristics are proper for the job. See IDENTIFICA TION,
page 3.
8
BURNER
The burner assembly is mounted on the flange of the combustion chamber,
fig. 14.
NOTE: Be certain combustion chamber opening is aligned with opening
in heater flange, fig. 14, before placing burner into heater .
1. Place the flange gasket over the 3/8" x 1/4" long studs on the flange.
2. Place the burner flange on the studs and into the heater flange
opening.
• Bring the factory wiring from the high limit /eco and thermostat into
the oil burner junction box.
• Install field and factory wiring as shown in the wiring diagrams,
figs. 15. A schematic diagram is also shown for convenience
when servicing.
• Ground the heater in accordance with the NEC code to guard
against electrical shock from the heater or water system.
3. All burners have "intermittent ignition" as defined by UL (ignition is on
during the time the burner is on and off when the burner is off).
4. Do not "test fire" the heater to complete the oil burner certificate until
the tank is filled with water, see the oil burner manual.
The certificate and this manual must be left with the user for future
reference.
TABLE 8 - OIL PUMP & NOZZLE SPECIFICATIONS
Fitting Rate (GPH)
Oil Burner Oil Burner
Non Pump Oil Burner Nozzle
Heater State State Non-Setting Nozzle Rating
Model Burner Burner PSIG Type (GPH)
COF-199 1.42 1.1 110 80ºB 1.35
COF-245 1.75 1.5 100 80ºB 1.75
COF-315/315A 2.25 2.0 100 80ºB 2.25
COF-385/385A 2.75 2.5 100 80ºB 2.75
COF-455/455A 3.25 3.0 100 80ºB 3.25
COF-700/700A 5.00 4.5 100 80ºB 5.00
ASSEMBLY OF THE OIL BURNER TO THE HEATER
FIGURE 14
3. Place the flat washers and lock washers over the studs and fasten the
burner in place with the 3/8" - 16 nuts as shown.
Connect the oil line(s) and electrical wires to the burner as follows:
1. The oil pump manufacturer's instructions should be checked for
connection and bleeding information.
• The burner is approved for use with fuel oil not heavier than No. 2.
2. An approved, separately fused circuit with disconnect switch should
be available for the oil burner. Using Figure 15, the wiring diagram
below as a guide:
• Route the 120 volt incoming line in the dual bulb thermostat,
mounted on the side of the heater.
FUEL PUMP
GENERAL
All heaters are shipped with the pump pressure set at 100 psig except
the COF-199 which is set at 110 psig.
All oil pumps are fitted for installation on single fuel line systems. The
pump may be adapted for two line service by using the by-pass Plug and
pump manufacturer's instructions packed with the burner.
The single-stage pumps are for single-pipe or two-pipe installations, either
lift or gravity feed. On gravity feed installations the inlet pressure is not to
exceed 3 psig. On one pipe lift installations the lift is not to exceed 8 ft.
The two-stage pumps are for two-pipe lift installations where the inlet
vacuum does not exceed 20" hg. vacuum.
AIR BLEED PROCEDURE (Refer to oil burner manual).
9
FIGURE 15
OPERATION
GENERAL
Never operate the heater unless the tank is filled with water and a
temperature and pressure relief valve is installed.
FILLING
1. Oil burner electrical disconnect switch should be in the "OFF" position
2. Close the heater drain valve.
3. Open a nearby hot water faucet to allow the air in the system to escape.
4. Fully open the cold water inlet valve, filling the heater and piping.
5. Close the hot water faucet as water starts to flow from the opening,
Leave the cold water inlet valve fully open. The heater is now ready to
start-up if being placed in operation for the first time.
START-UP
The following checks should be made by the installer when the heater is
placed into operation for the first time:
1. Check all factory and field made water, oil and electrical connections
for tightness. Also check flue gas disposal provisions on top the heater .
• Repair any water and oil leaks. Tighten electrical and flue
connections as necessary.
2. Where the water heater or water heating systems includes a
circulating pump, it may need to be lubricated before operated. The
tube of lubricant supplied with the pump includes directions for use.
• Field installed circulating pumps should be all bronze construction.
Be sure the oil burner, related piping, valves and controls are in place,
adjusted and ready for operation before turning on the electricity.
3. Adjust the heater mounted control as follows:
• THERMOSTAT (adjustable) set for desired water temperature.
• It is suggested the thermostat be turned to the lowest setting
which satisfies the hot water requirements of the system. This
helps minimize scale formation in the heater.
• HIGH LIMIT (not adjustable, manual reset) factory set to cutout at
195° F (90.5°C).
• If the high limit is actuated, the safety primary control will cause the oil
burner to shut down. See SAFETY PRIMARY CONTROL, page 21.
• To reset the safety primary control, depress and hold the red
button on the control for 30 seconds until the LED flashes twice.
• Depress red button one time only. If burner does not operate after
depressing red button one time, call service man.
4. Turn on the oil burner electrical disconnect switch.
5. The heater will begin normal operation on the thermostat's "call for heat".
10
6. To turn the heater off, open the electrical disconnect switch. If the
heater is to remain inoperative for a long period of time, close the
shutoff valve on the oil supply line.
WA TER TEMPERA TURE CONTROL
and may be set for 120° (48.9°C) to 180°F (82.2°C) water
temperature, but 120°F (48.8°C) is the recommended starting point.
It is suggested the dial be placed in the lowest setting which produces
an acceptable hot water supply. This will always give the most
energy efficient operation. The temperature control has a 4°F (2.2°C)
fixed differential.
HIGH LIMIT SWITCH (E.C.O)
The dual bulb controller (fig.17) contains the high limit (energy cutoff)
sensor. The high limit switch interrupts main burner gas flow should
the water temperature reach 195°F (90.5°C).
In the event of high limit switch operation, the appliance cannot be
restarted unless the water temperature is reduced by 20°F
(11.1°C)(approx.) and the high limit reset button on front of limit control
(fig.17) is depressed.
DANGER
THIS WATER HEATER IS EQUIPPED WITH AN ADJUSTABLE
THERMOSTAT TO CONTROL W ATER TEMPERATURE. HOT WATER
TEMPERATURES REQUIRED FOR AUTOMATIC DISHWASHER AND
LAUNDRY USE CAN CAUSE SCALD BURNS RESULTING IN
SERIOUS PERSONAL INJURY AND OR DEA TH. THE TEMPERA TURE
AT WHICH INJURY OCCURS VARIES WITH THE PERSONS AGE
AND TIME OF EXPOSURE. THE SLOWER RESPONSE TIME OF
CHILDREN, AGED OR DISABLED PERSONS INCREASES THE
HAZARDS TO THEM. NEVER ALLOW SMALL CHILDREN TO USE
A HOT WATER TAP, OR TO DRAW THEIR OWN BATH WATER.
NEVER LEAVE A CHILD OR DISABLED PERSON UNATTENDED IN A
BATHTUB OR SHOWER.
THE WATER HEATER SHOULD BE LOCATED IN AN AREA WHERE
THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO SET
TEMPERA TURES.
SETTING THE WATER HEA TER TEMPERA TURE AT 120°F (48.9°C) WILL
REDUCE THE RISK OF SCALDS. Some states require settings at specific
lower temperatures.
Figure 16 shows the approximate time-to-burn relationship for normal
adult skin. Short repeated heating cycles caused by small hot water
uses can cause temperatures at the point of use to exceed the
thermostat setting by up to 20°F. If you experience this type of use,
you should consider using lower temperature settings to reduce
scald hazards.
Continued manual resetting of high limit control, preceded by higher
than usual water temperature is evidence of high limit switch
operation. Contact your dealer or servicer if continued high limit
switch operation occurs.
DUAL-BULB THERMOSTA T (COVER REMOVED)
FIGURE 17
BURNER CERTIFICA TE (COMBUSTION TEST)
The Commercial Standard CS75 Oil Burner Certificate form must be filled
in and posted in the vicinity of the water heater.
Temperature Time to Produce 2nd & 3rd
Setting Degree Burns on Adult Skin
180°F (82.2°C) Nearly instantaneous
170°F (76.6°C) Nearly instantaneous
160°F (71.1°C) About 1/2 second
150°F (65.5°C) About 1-1/2 seconds
140°F (60.0°C) Less than 5 seconds
130°F (54.4°C) About 30 seconds
120°F (48.9°C) More than 5 minutes
FIGURE 16
Valves for reducing point-of-use temperature by mixing cold and hot
water are available. Also available are inexpensive devices that attach
to faucets to limit hot water temperatures. Contact a licensed plumber
or the local plumbing authority.
The water temperature is controlled by a thermostat, fig. 17, which
has two sensing elements. One sensor is located near the top of
the tank and the other is near the center. The thermostat is set in the
lowest position before the heater leaves the factory.
The thermostat temperature dial, fig. 17, is accessible by taking off the
access cover and removing the control cover. The dial is adjustable
Instructions for filling in certificate are on the back of the certificate. This
must be done by the installer at the time the heater is first operated. The
certificate is in the oil burner manual.
SELF-CLEANING ELIMINATOR
These units include a self-cleaning eliminator installed in the front
water inlet. See figure 18. The eliminator must be oriented correctly
for proper function. There is a marked range on the pipe nipple
portion of the eliminator, 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
eliminator to reduce the probability of misaligning the eliminator
accidentally while tightening the connection to the inlet water supply
line. Improper orientation of the eliminator can cause poor
performance of the heater and can significantly reduce outlet water
temperatures during heavy draws.
FIGURE 18
11
DRAINING
The water heater must be drained if it is to be shut down and exposed to
freezing temperatures. Maintenance and service procedures may also
require draining the heater.
1. Turn off the oil burner electrical disconnect switch.
• If required by the reason for draining the heater, turn off the oil
line supply valve.
2. Close the cold water inlet valve to heater.
3. Open a nearby hot water faucet to vent the system.
4. Open the heater drain valve.
5. If the heater is being drained for an extended shutdown, it is suggested
the drain valve be left open during this period.
• Follow FILLING instructions when restarting hot water service.
If water does not flow, remove the valve and inspect for obstructions or
corrosion. Replace with a new valve of the recommended size as necessary.
Inspection of the valve should be performed at least every three years. Do not
attempt to repair the valve, as this could result in improper operating and a tank
explosion. In areas with poor water conditions, it may be necessary to inspect
the T&P valve more often than twice a year.
DANGER
BEFORE MANUALLY OPERA TING A RELIEF V AL VE, MAKE SURE THA T
DRAIN LINE HAS BEEN ATTACHED TO THE VALVE TO DIRECT THE
DISCHARGE TO AN OPEN DRAIN. FAILURE TO TAKE THIS PRECAUTION
COULD MEAN CONT ACT WITH EXTREMELY HOT W A TER PASSING OUT
OF THE V ALVE DURING THIS CHECK OPERA TION.
If the temperature and pressure relief valve on the heater discharges
periodically or continuously, it may be due to thermal expansion of water
in a closed water supply system, or it may be due to a faulty relief valve.
Thermal expansion is the normal response of water when it is heated. In
a closed system, thermal expansion will cause the system pressure to
build until the relief valve actuation pressure is equaled. Then, the relief
valve will open, allowing water to escape, slightly lowering the pressure.
MAINTENANCE
GENERAL
Water heater maintenance includes periodic tank flushing and cleaning, and
removal of lime scale. The oil burner should be inspected and adjusted to
maintain proper combustion. Where used, the water heating system circulating
pump should be oiled (See table 9).
The depth of lime buildup should be measured periodically. Heaters will have
about 2" (50.8 mm) of lime buildup when the level of lime has reached the
bottom of the cleanout opening or about 1" of lime buildup if it has reached the
drain valve opening. A schedule for deliming should be setup, based on the
amount of time it would take for a 1" (25.4 mm) buildup of lime.
Example 1: Initial inspection shows 1/2" (12.7 mm) of lime accumulation.
Example 2: Initial inspection shows 2" (50.8 mm) of lime accumulation.
Following are the instructions for performing some of the recommended
maintenance. Oil burner inspection and adjustment should be performed by a
competent technician.
Relief Valve Lift Lever Annually
Circulating Four SAE No. 20 non-detergent
Oil Burner
Flue Baffle
Venting Semi-
System Inspected Annually
* Replacement gasket, A.O. Smith Part No. 99038
Therefore, the heater can be delimed once a year.
Therefore, the heater should be delimed every 3 months.
TABLE 9 SUGGESTED MAINTENANCE SCHEDULE
Semi-
Flushing Monthly
Sediment SemiRemoval Annually
Anode Semi
Tank
Pump Oiling Months motor oil
Pipe Cleaning Annually Wire Brush
Inspection Annually
Lime Scale As UN•LIME
Removal Required Delimer
Inspection Combustion test
and Semi- kit & test specifications
Adjustment Annually (Page 26)
Nozzle Semi-
Replacement Annually New Nozzle
®
Your water supplier or local plumbing inspector will know how to best
correct this situation. Two common corrections are listed in the Checklist
and Service Information which appears later in this manual.
ABOVE ALL, DO NOT PLUG THE TEMPERATURE AND PRESSURE RELIEF
VALVE. THIS IS NOT A SOLUTION AND CAN CREA TE A HAZARDOUS
SITUA TION.
FLUSHING
1. Turn off the oil burner electrical disconnect switch.
2. Open the drain valve and allow water to flow until it runs clean.
3. Close the drain valve when finished flushing.
4. Turn on the oil burner electrical disconnect switch.
SEDIMENT REMOV AL
Water borne impurities consist of fine particles of soil and sand which
settle out and form a layer of sediment on the bottom of the tank.
For convenience, sediment removal and lime scale removal should be
performed at the same time.
LIME SCALE REMOVAL
The amount of calcium carbonate (Lime) released from water is in
direct proportion to water temperature and usage, see chart. The higher
the water temperature or water usage , the more lime deposits are
dropped out of the water. This is the lime scale which forms in pipes,
heaters and on cooking utensils.
RELIEF V AL VES
At least twice a year, the system relief valves should be checked to
ensure that they are in operating condition. To check a relief valve, lift the
lever at the end of the valve several times. The valve should seat properly
and operate freely.
WA TER USAGE IN GALLONS PER DA Y POUNDS OF LIME
DEPOSITED VS. TEMPERATURE AND WA TER USAGE
12
Lime accumulation not only reduces the life of the equipment but
also reduces efficiency of the heater and increases fuel
consumption.
The usage of water softening equipment greatly reduces the
hardness of the water. However, this equipment does not always
remove all of the hardness (lime). For this reason it is recommended
that a regular schedule for deliming be maintained.
• Remove drain valve from heater and insert a 3/4" x 4" drain nipple.
• Connect the clamp 1" I. D. x 3" hole to Flo-Jug and drain nipple.
3. Lift the Flo-Jug to the POUR POSITION and permit the UN•LIME
flow into the heater as rapidly as possible.
• Be sure to keep the vent just above the liquid level.
®
to
Sediment and lime scale removal may be accomplished through the
cleanout opening furnished on the water heater, see FEATURES,
page 2. The heater must be drained, see DRAINING, page 12, before
removing cleanout cover on tank.
To dissolve and remove the more stubborn mineral deposits, A.O.
Smith UN•LIME® Professional Delimer or equivalent should be
used.
A.O. Smith UN•LIME
®
Delimer is an easy-to-handle patented food grade
acid formulated specifically for lime scale removal from all types of
water using equipment and is available in 1 gallon (Part No. 4763) and
5 gallon (Part No. 4813) sizes. Hydrochloric base acids are not
recommended for use on glass-lined tanks.
A.O. Smith Form No. 4800, entitles Why? When? & How?
describes tank cleaning methods and materials. UN•LIME® and
booklet may be obtained through your A.O. Smith dealer or
distributor.
To clean heater through cleanout opening, proceed as follows:
1. Turn off water inlet valve, the oil burner electrical disconnect
switch and open drain valve and allow all water to be drained
from heater.
2. Remove outer cover plate from lower side of heater jacket.
3. Remove six (6) hex head screws securing tank cleanout plate and
remove plate.
4. Place the Flow-Jug in the DELIME POSITION.
• It may be necessary to place the empty jug on its carton to trap
the solution in the heater.
• Allow the UN•LIME
®
to attack the water scale for 5 minutes.
5. Lower the Flo-Jug to the DRAIN POSITION and allow the UN•LIME
to flow out of the heater as rapidly as possible.
• Observe the vent hole and elevate the jug slightly if there is a
possibility of spillage.
• Deliming activity is indicated by foaming on the surface of the
solution.
6. Continue the deliming process:
• Raise jug to POUR POSITION. Allow solution to flood into heater.
• Place jug to DELIME POSITION for 5 minutes. Solution is at work in
heater.
• Lower jug to DRAIN POSITION and allow solution to flow out.
Observe foaming.
®
4. Remove lime, scale. or sediment using care not to damage the glass
lining.
5. Inspect cleanout plate gasket. If new gasket is required, replace
with A.O. Smith Part no. 99038.
6. Install cleanout plate. Be sure to draw plate up tight by tightening
screws securely.
7. Close drain valve, open water inlet line and turn on the oil burner
electrical disconnect switch.
8. Check for water leakage.
9. Replace outer jacket cover plate.
Flo-jug Method of Deliming
The Flo-Jug is the standard 5 gallon container for UN•LIME® -or- it is
available as a deliming kit with UN•LIME®, hose and fittings. Contact
your dealer, distributor or the A.O. Smith Water Products Company.
Figure 18 illustrates most of the following steps.
1. The heater should be prepared for deliming as described in the
"Why? When and How" booklet. The relief valve may also be delimed
at this time.
2. With the Flow-Jug upright:
• Take off cap, remove cover under opening and install 3/4" x 4"
brass pipe nipple.
• Drill or punch a 3/16" vent hole in handle. A stainless steel screw
is included with the Flo-Jug kit. This screw is to be installed in the
vent hole when Flo-Jug is not in use.
DELIMING THE COF WA TER HEATER
FIGURE 18
7. After one hour, or earlier if the deliming activity (foaming) stops,
inspect the tank interior.
• Drain the UN•LIME® back into jug, DRAIN POSITION, and then
standjug in DELIME POSITION.
• Remove clamp, hose and pipe nipple from heater drain opening.
• Observe interior through opening - a small flashlight works
well.
• If the interior still shows water scale, the deliming process
should be continued.
• To check UN•LIME® for continued use or reuse, place
some lime scale or white chalk into a glass with a small
13
amount of the solution. If the material is vigorously dissolved by
the solution, the UN•LIME® can be reused. If not, then UN•LIME®
has been weakened and should be replaced.
8. When deliming has been completed, the heater should be flushed
for 3 to 5 minutes with fresh water.
• Remove the deliming equipment, install the drain valve, open
the cold water inlet line and allow water to flow through heater
and out the drain valve. Don't forget to plug vent and cap
opening in Flo-Jug.
9. When flushing is completed:
• Fill heater being certain to expel air from tank through a nearby
hot water faucet.
• Replace relief valve, removed for deliming.
• Restore oil, water and electrical supply to heater.
• Check for water leakage.
10.Flo-Jug Cleanup.
• Allow scale to separate from UN•LIME® and settle on bottom
of Flo-Jug.
• Pour off UN•LIME® into plastic container and check for reuse.
• Rinse sediment from Flo-Jug.
• If UN•LIME® is reusable , pour back into Flo-Jug. Be sure to plug
vent and cap opening.
CIRCULA TING PUMP
The water heater or water heating system may include a circulating
pump. Where used, it may need to be lubricated once every four months
with SAE No. 20 non-detergent motor oil or as directed by the
manufacturer.
• Place 2 or 3 teaspoons in the bearing oil cup and 10 to 12 drops in
the
motor oil cups.
SOOT REMOVAL
Soot must be removed semi-annually from the heater and flow passages
to insure efficient operation of the heater.
A TYPICAL HEA TER FLUEW A Y AND FLUE BAFFLE
FIGURE 19
1. Remove chimney connector and top cover of heater from heater.
Clean out all soot deposits from connector and chimney opening. A
wire brush is recommended for this operation.
2. Remove flue baffles by lifting from tank.
3. Using a wire brush, remove soot from flue passages in heater tank.
CAUTION: While cleaning tank flue passages, care must be taken that
brush does not come in contact with the top of the combustion
chamber as damage could occur to the combustion chamber
lining. Do not allow the brush to enter the heater flue more
than noted in fig. 19.
4. Remove oil burner assembly and using a vacuum cleaner , remove all loose
soot from combustion chamber area. Avoid contact with combustion
chamber as it can be damaged quite easily.
• If flange gasket is damaged, replace with A.O. Smith Part No. 24165
5. Upon completion of cleaning, reassemble the heater. (It may be necessary
to apply new sealer tape to the top cover to ensure proper venting. New
sealer tape can be ordered from A.O. Smith Water Products Company).
6. Return the heater to operation by following the start-up instructions on
page 1 1 .
VENT SYSTEM
Examine the vent system every six months for obstructions and/or
deterioration of vent piping. Remove any soot or obstructions and
replace damaged vent piping.
14
INST ALLATION DIAGRAMS
ONE TEMPERA TURE - ONE HEATER VERTICAL STORAGE TANK FORCED
CIRCULA TION WITH OR WITHOUT BUILDING RECIRCULATION
NOTE:
WHEN USING A A.O. Smith T-140,200,350,OR 400 STORAGE TANK,
USE LOWER 3/4" OPENING FOR TANK TEMP.CONTROL
SCALD PREVENTION
HOT WATER CAN SCALD IF USED
CARELESSLY OR IN UNANTICIPATED
MANNER.
CAUTION
IF BUILDING COLD WATER SUPPLY HAS
A BACK FLOW PREVENTER, CHECK
VALVE OR WATER METER WITH CHECK
VALVE, PROVISIONS FOR THERMAL
EXPANSION OF WATER IN THE HOT
WATER SYSTEM MUST BE PROVIDED.
NOTE: CONNECT RETURN LINE FROM
HOT WATER CIRCULATING LOOP
(IF USED) TO COLD WATER INLET LINE.
INSET B
VACUUM RELIEF VALVE
INSTALL PER LOCAL CODES.
ONE TEMPERATURE - ONE HEATER HORIZONTAL STORAGE T ANK FORCED
CIRCULA TION WITH OR WITHOUT BUILDING RECIRCULATION
DANGER:
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
TEMPERATURES AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 11. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
INSET A
INSTALL THERMAL EXPANSION
TANK IN COLD WATER SUPPL Y LINE,
IF CHECK VALVE OR PRESSURE
REDUCING VALVE IS USED IN
SUPPLY.
* PIPE TO OPEN DRAIN
INST ALL IN ACCORDANCE WITH LOCAL CODES
15
WIRING DIAGRAM FOR HEATER T O TANK LOOP
AND /OR HOT WATER LOOP (IF USED)
SINGLE TEMPERA TURE OR BOOSTER
DANGER:
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
TEMPERATURES AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 11. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
TWO TEMPERATURE - ONE HEATER HIGH TEMPERA TURE STORAGE
WITH OR WITHOUT RECIRCULA TION
NOTE: IF TEMPERED WATER IS RECIRCULATED
RETURN LINE SHOULD BE CONNECTED
AT POINT "A"
* PIPE TO OPEN DRAIN
RETURN LINE FROM 180°F (82.2°C)
CIRCULATING LOOP (IF USED)
INSET B
VACUUM RELIEF VALVE
INSTALL PER LOCAL CODES.
INSET A
INSTA LL THERMAL EXP ANSION TANK
IN COLD WATER SUPPLY LINE, IF
CHECK VALVE OR PRESSURE
REDUCING VALVE IS USED IN
SUPPLY.
INSTALL IN ACCORDANCE WITH LOCAL CODES
WIRING DIAGRAM FOR TEMPERED WATER LOOP
(IF USED)
WIRING DIAGRAM FOR 180° LOOP (IF USED)
16
TWO TEMPERTURE - TWO HEA TERS HIGH TEMPERATURE STORAGE
WITH OR WITHOUT RECIRCULA TION
DANGER:
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
TEMPERATURES AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 11. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
* PIPE RELIEF VALVE TO OPEN DRAIN
NOTE: IF TEMPERED WATER IS RECIRCULATED, RETURN LINE
SHOULD BE CONNECTED AT POINT "A"
FOR MULTIPLE HEATER INSTALLATION SEE MANIFOLD KIT
SPECIFICATIONS, PAGES 22-23
INSTALL IN ACCORDANCE WITH LOCAL CODES
WIRING DIAGRAM FOR TEMPERED WATER LOOP
(IF USED)
INSET B
VACUUM RELIEF VALVE
INSTALL PER LOCAL CODES.
WIRING DIAGRAM FOR 180° LOOP (IF USED)
INSET A
INSTA LL THERMAL EXP ANSION TANK
IN COLD WATER SUPPLY LINE, IF
CHECK VALVE OR PRESSURE
REDUCING VALVE IS USED IN
SUPPLY.
17
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