A.O. Smith COF-245, COF-315A, COF-385A, COF-455A, COF-700A Installation Manual
MODELS COF-199 THRU 700A
COMMERCIAL OIL FIRED WATER HEATER FOR HOT WATER SUPPLY
• Installation • Service • Maintenance
TEXT PRINTED OR OUTLINED IN RED CONTAINS INFORMATION
CAUTION
RELATIVE TO YOUR SAFETY. PLEASE READ THOROUGHLY BEFORE
USING APPLIANCE.
500 Tennessee Waltz Parkway
Ashland City, TN 37015
www.hotwater.com
PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND
PRINTED 0315 193472-006
NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.
1
FEATURES AND SPECIFICATIONS
TEXT PRINTED OR OUTLINED IN RED CONTAINS INFORMATION
RELATIVE TO YOUR SAFETY. PLEASE READ THOROUGHLY BEFORE
USING APPLIANCE.
This is a typical Duraclad oil-red heater for commercial water heating
applications. The principal components of the heater are shown and
identied here. The identication 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
COF - 199 COF - 245 COF - 315/315A COF - 385/385A COF - 455/455A COF - 700/700A
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 3/4 933 36 3/4 933 36 3/4 933 36 3/4 933
C 27 3/4 705 27 3/4 705 27 3/4 705 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 5/8 676 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 sufx "A" indicates the optional A.S.M.E. tank construction.
TANK APPROX U.S Gallons/Hr. and Litres/Hr at TEMPERATURE RISE INDICATED
CAPACITY EFF. F° 40F° 50F° 60F° 70F° 80F° 90F° 100F° 110F° 120F° 130F° 140F°
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 efciency. Above 2,000 altitude, input
ratings should be reduced 4% for each 1000' above sea level.
TABLE 2 RECOVERY CAPACITIES, based on 80% thermal efciency
2
TABLE OF CONTENTS
FEATURES AND SPECIFICATIONS ............................................ 2
APPROVALS ................................................................................. 3
IDENTIFICATION
Oil and Burner Nameplate Decal ......................................... 3
Oil Burner Specications ..................................................... 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
Water Temperature Control .................................................. 11
High Limit Switch E.C.O. ..................................................... 11-12
Burner Certicate (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
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.
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).
HLW
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 Figure 1 on page 2 for approximate
location of the heater rating plate.
The heater rating plate model number, see g. 2, includes a series number
which identies the construction of the heater.
OIL BURNER NAMEPLATE 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.
COF 455 940
455,000
120
3.25
10
CO5MOO6721
XXX.X XX
60
A TYPICAL HEATER RATING PLATE
FIGURE 2
XXXXXXXXXX
XXX
A TYPICAL OIL BURNER NAMEPLATE DECAL
FIGURE 3
3
OIL BURNER SPECIFICATIONS
The oil burner nameplate decal includes a series code which identies 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.
TABLE 3 SOME NOTABLE OIL BURNER FEATURES
A.O.
Smith
Burner
or Heater
Series
Number*
940
941
* To provide the proper ring rate for each model heater, see SPECIFICATIONS:
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 specied for the installation.
+ All oil burners have "interrupted ignition" . . . meaning the ignition is on during
the ame establishing period only. Ignition is off when the burner is off. Standard
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
single-stage oil pump can be used. The 940 series of burners have
single-stage 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 signicantly 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 modied to operate without the
line, see the oil burner installation manual.
The oil-red 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. To assure matching equipment, see preceding information.
COF COF COF COF COF COF
Model Heater 199 245 315/315A 385/385A 455/455A 700/700/A
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
R.W.
Becket
Burner
Model
Number
AFG
AFG SF15 Sec.
SF
Safety
Timing+
15 Sec.
15 Sec.
Oil
Pump
Type
Mode
Single
Stage
Two-
Stage
IMPORTANT
TABLE 3A
Suntec Oil
Pump
A2VA
7118
A2YA-
7916
B2VA
8216
BY2A
8916
Nozzle Type
Spray
Pattern
Type B
Solid
Cone
Type B
Solid
Cone
Spray
Angle
80°
80°
SAFETY
BE SURE TO TURN OFF POWER WHEN WORKING ON OR NEAR THE
ELECTRICAL SYSTEM OF THE HEATER. NEVER TOUCH ELECTRICAL
COMPONENTS WITH WET HANDS OR WHEN STANDING IN WATER. WHEN
REPLACING FUSES ALWAYS USE THE CORRECT SIZE FOR CIRCUIT.
DANGER
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.
INSTALLATION
REQUIRED ABILITY
INSTALLATION OF SERVICE OF THIS WATER HEATER 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 specic questions of wiring, air adjustment, etc.
Do not test the burner or control system before the heater is lled with
water. Follow the START-UP procedure in this manual.
UNCRATING
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
The water heater should not be installed where the combustion air is
contaminated, see COMBUSTION AND VENTILATING AIR. Temperature
in the location must be above 32°F (0°C) and free of combustible dusts
and ammable 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 oor 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 oors 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 ow.
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 oor 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 g. 4A to prevent possible
re hazard conditions.
At least 24" (610 mm) of top clearances are recommended for vertical
vent installation.
Allow sufcient room at rear of heater for servicing of T&P relief valve.
At least 24" (610 mm) should be provided at front of the unit for proper servicing.
Units which are to be installed on combustible ooring must be supported
by a full layer of hollow concrete blocks, g. 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 Figure 4.
CHEMICAL VAPOR 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 SPACES (Building Construction)
NOTE: An uncontaminated space is dened as a space whose volume is
not less than 50 ft
all fuel burning appliances installed in that space. The unconned
space may be thought of as extending to all areas which cannot
be separated by a door or door(s). All other spaces not tting this
description, should be thought of as conned space.
1. In unconned spaces in buildings of conventional frame, brick or
stone construction, inltration will normally supply an adequate amount
of air for combustion and ventilation.
2. If the unconned space is within a building of tight construction, eg.
weather stripping, heavy insulation, caulking, vapor barrier, ect.,
air inltration may be insufcient 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 Conned Spaces (Room
Construction)
3
per 1000 BTUH (4.83m3 per kW)of total input of
PROPER INSTALLATION ON COMBUSTIBLE FLOORING
FIGURE 4
NOTE: If electrical conduits run under the oor of the proposed heater
location, insulate the oor as recommended above.
PROPER INSTALLATION CLEARANCES FOR TWO DIFFERENT
VENTING SYSTEMS
FIGURE 4A
* HOT WATER OUTLET LOCATION AT FRONT OF HEATER
• FACTORY FURNISHED HEATER 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 sufcient 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 NFPA Standard No. 31, Chapter 1.
5
CONFINED SPACES (Room Construction)
1. All air from inside building (conventionally constructed buildings only):
The conned space shall be provided with two permanent openings,
one within 12" (305 mm) of the ceiling and one within 12" (305 mm)
of the oor, g. 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 conned 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.
• 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 mm
2
/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 mm
2
/kW) (70 square inches per gallon of oil
consumed per hour) of total input of all appliances in the
enclosure, fig. 6.
TABLE 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 ue 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 ue 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 REGULATOR
The chimney or vent connector diameter should be the same size as
the heater ue 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, g. 7. The connector length should
be kept as short as possible.
PROPER VENT CONNECTOR INSTALLATION
FIGURE 7
CHIMNEY
The oil-red 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 ue 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.
Oil Equivalent Output Square & Rectangle
Firing Heat Input Heat Stack Round Stack Minimum
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
TABLE 5 - USUAL CHIMNEY SIZES FOR UNITS
6
MULTIPLE HEATER FLUES
DRAIN VALVE AND ACCESS PANELS
When two or more oil-red water heaters are connected to a single chimney
or vent there shall be sufcient 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-red water heater should be connected to any one type L
venting system.
A draft regulator shall be provided for each oil-red water heater in a
multiple heater system.
DANGER
INCORRECT INSTALLATION CAN CAUSE IMPROPER OPERATION,
FIRE, ASPHYXIATION, SERIOUS PERSONAL INJURY OR DEATH. NEVER
OPERATE THIS WATER HEATER UNLESS IT IS PROPERLY 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 ow through
the heater.
RELIEF VALVE
An CSA design-certied 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 VALVES BETWEEN THE HEATER 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.
Your local code authority may have other specic 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-ow 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.
7
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 ame observation port, g. 8. A plug is inserted into the ame
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,
g. 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. To 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 certicate 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 certicate (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 tted 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.
A TYPICAL HEATER INSTALLATION - 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, g. 11. The fuel oil will ow 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).
Distance Max. Distance Max.
Tank 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)
TABLE 6
Two Stage, Supply and Return Lines: This system, g. 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
single-line 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,
g. 12, is self-priming. Burner Series No. 940 with by-pass plug
eld 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 INSTALLATION - 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.
Tank 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 INSTALLATION
A SINGLE STAGE (LOW LIFT), SUPPLY AND RETURN
LINE INSTALLATION - FIGURE 12
GENERAL
An oil Burner Certicate is packed with the oil burner. Following the burner
manual installation the necessary tests shall be performed and results
recorded on the certicate, see BURNER CERTIFICATE. The certicate
and this instruction manual must be left with 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 IDENTIFICATION,
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 ange, g. 14, before placing burner into heater .
• Bring the factory wiring from the high limit /eco and thermostat into
the oil burner junction box.
• Install eld and factory wiring as shown in the wiring diagrams,
gs. 15. A schematic diagram is also shown for convenience when
servicing.
1. Place the ange gasket over the 3/8" x 1/4" long studs on the
ange.
2. Place the burner ange on the studs and into the heater ange
opening.
ASSEMBLY OF THE OIL BURNER TO THE HEATER
FIGURE 14
3. Place the at 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.
• Ground the heater in accordance with the NEC code to guard against
electrical shock from the heater or water system.
3. All oil burners have "interrupted ignition". . . meaning the ignition is on
during the ame establishing period only.
4. Do not "test re" the heater to complete the oil burner certicate until
the tank is lled with water, see the oil burner manual.
The certicate 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
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 tted 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 lled 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, lling the heater and piping.
5. Close the hot water faucet as water starts to ow 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 rst time.
START-UP
Factory Start-Up is required for activating warranty and assuring maximum
operating performance. Contact your local sales representative or
Authorized Start-Up Agent to arrange a FREE Certied Start-Up.
The following checks should be made by the installer when the heater is
placed into operation for the rst time:
1. Check all factory and eld made water, oil and electrical connections for
tightness. Also check ue 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
satises 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 22.
• To reset the safety primary control, depress and hold the red button
on the control for 30 seconds until the LED ashes 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.
WATER TEMPERATURE 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 (g.17) contains the high limit (energy cutoff)
sensor. The high limit switch interrupts main burner gas ow 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.
THIS WATER HEATER IS EQUIPPED WITH AN ADJUSTABLE
DANGER
THERMOSTAT TO CONTROL WATER TEMPERATURE. HOT WATER
TEMPERATURES REQUIRED FOR AUTOMATIC DISHWASHER
AND LAUNDRY USE CAN CAUSE SCALD BURNS RESULTING IN
SERIOUS PERSONAL INJURY AND OR DEATH. THE TEMPERATURE
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
TEMPERATURES.
SETTING THE WATER HEATER TEMPERATURE AT 120°F (48.9°C)
WILL REDUCE THE RISK OF SCALDS. Some states require settings at
specic 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 THERMOSTAT (COVER REMOVED)
FIGURE 17
BURNER CERTIFICATE (COMBUSTION TEST)
The Commercial Standard CS75 Oil Burner Certicate form must be lled
in and posted in the vicinity of the water heater.
st
Water Temperature °F
110 (normal shower temp.)
116 (pain threshold)
116 35 minutes 45 minutes
122 1 minute 5 minutes
131 5 seconds 25 seconds
140 2 seconds 5 seconds
149 1 second 2 seconds
154 instantaneous 1 seconds
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong, Sept. 15, 1978)
Time for 1
Degree Burns
(Less Severe Burns)
Time for Permanent Burns
2nd & 3rd Degree
(Most Severe Burns)
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, g. 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, g. 17, is accessible by taking off
the access cover and removing the control cover. The dial is adjustable
11
Instructions for lling in certicate are on the back of the certicate. This
must be done by the installer at the time the heater is rst operated. The
certicate 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
DRAINING
The water heater must be drained if it is to be shut down or 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.
MAINTENANCE
GENERAL
Water heater maintenance includes periodic tank ushing 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.
Semi-
Relief Valve Lift Lever Annually
Flushing Monthly
Sediment Semi-
Removal Annually
Anode Semi
Tank
Lime Scale As UN•LIME
Removal Required Delimer
Circulating Four SAE No. 20 non-detergent
Inspection Combustion test
and Semi- kit & test specications
Oil Burner
Nozzle Semi-
Flue Bafe
Venting Semi-
System Inspected Annually
Therefore, the heater can be delimed once a year.
Therefore, the heater should be delimed every 3 months.
TABLE 9 SUGGESTED MAINTENANCE SCHEDULE
Inspection Annually
Pump Oiling Months motor oil
Adjustment Annually (Page 26)
Replacement Annually New Nozzle
Pipe Cleaning Annually Wire Brush
®
If water does not ow, 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 OPERATING A RELIEF VALVE, MAKE SURE
THAT DRAIN LINE HAS BEEN ATTACHED TO THE VALVE TO DIRECT
THE DISCHARGE TO AN OPEN DRAIN. FAILURE TO TAKE THIS
PRECAUTION COULD MEAN CONTACT WITH EXTREMELY HOT WATER
PASSING OUT OF THE VALVE DURING THIS CHECK OPERATION.
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.
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 CREATE A
HAZARDOUS SITUATION.
FLUSHING
1. Turn off the oil burner electrical disconnect switch.
2. Open the drain valve and allow water to ow until it runs clean.
3. Close the drain valve when nished ushing.
4. Turn on the oil burner electrical disconnect switch.
SEDIMENT REMOVAL
Water borne impurities consist of ne 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.
* Replacement gasket, A.O. Smith Part No. 99038
RELIEF VALVES
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.
WATER USAGE IN GALLONS PER DAY POUNDS OF LIME
DEPOSITED VS. TEMPERATURE AND WATER USAGE
FIGURE 18A.
12
Lime accumulation not only reduces the life of the equipment but also
reduces efciency 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.
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.
• 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.
• 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
®
to
ow into the heater as rapidly as possible.
• Be sure to keep the vent just above the liquid level.
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 specically 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.
UN•LIME
®
Professional Delimer:
Part No: 9005416105 4 - 1 Gallon (case)
Part No: 9005417105 1 - 5 Gallon
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. Remove lime, scale. or sediment using care not to damage the
glass lining.
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 ow 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 ood 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 ow out.
Observe foaming.
®
5. Inspect cleanout plate gasket. If new gasket is required, replace with
A. O. Smith Kit (Part no. 9004099215).
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 Corporation. Figure 18 illustrates most of the
ollowing 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.
13
DELIMING THE COF WATER 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 stand jug in DELIME POSITION.
• Remove clamp, hose and pipe nipple from heater drain opening.
• Observe interior through opening - a small ashlight 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
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 ushed 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 ushing 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.
CIRCULATING 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. Lubricate as required by manufacturer.
SOOT REMOVAL
Soot must be removed semi-annually from the heater and ow passages
to insure efcient operation of the heater.
A TYPICAL HEATER FLUEWAY 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 ue bafes by lifting from tank.
3. Using a wire brush, remove soot from ue passages in heater tank.
CAUTION: While cleaning tank ue 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 ue more
than noted in g. 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 ange 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 11.
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
INSTALLATION DIAGRAMS
ONE TEMPERATURE - ONE HEATER VERTICAL STORAGE TANK FORCED
CIRCULATION WITH OR WITHOUT BUILDING RECIRCULATION
SCALD PREVENTION
HOT WATER CAN SCALD IF USED
CARELESSLY OR IN UNANTICIPATED
MANNER.
NOTE:
WHEN USING A A.O. Smith T-140,200,350,OR 400 STORAGE TANK,
USE LOWER 3/4" OPENING FOR TANK TEMP.CONTROL
INSET B
VACUUM RELIEF VALVE
INSTALL PER LOCAL CODES.
IF BUILDING COLD WATER SUPPLY HAS A
CAUTION
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.
ONE TEMPERATURE - ONE HEATER HORIZONTAL STORAGE TANK FORCED
CIRCULATION 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
* PIPE TO OPEN DRAIN
INSTALL IN ACCORDANCE WITH LOCAL CODES
15
INSTALL THERMAL EXPANSION
TANK IN COLD WATER SUPPLY LINE,
IF CHECK VALVE OR PRESSURE
REDUCING VALVE IS USED IN
SUPPLY.
WIRING DIAGRAM FOR HEATER TO TANK LOOP
AND /OR HOT WATER LOOP (IF USED)
SINGLE TEMPERATURE OR BOOSTER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
DANGER:
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 TEMPERATURE STORAGE
WITH OR WITHOUT RECIRCULATION
INSET B
VACUUM RELIEF VALVE
INSTALL PER LOCAL CODES.
NOTE: IF TEMPERED WATER IS RECIRCULATED
RETURN LINE SHOULD BE CONNECTED
AT POINT "A"
* PIPE TO OPEN DRAIN
INSTALL IN ACCORDANCE WITH LOCAL CODES
WIRING DIAGRAM FOR TEMPERED WATER LOOP
(IF USED)
RETURN LINE FROM 180°F (82.2°C)
CIRCULATING LOOP (IF USED)
INSET A
INSTALL THERMAL EXPANSION
TANK IN COLD WATER SUPPLY LINE,
IF CHECK VALVE OR PRESSURE
REDUCING VALVE IS USED IN
SUPPLY.
WIRING DIAGRAM FOR 180° LOOP (IF USED)
16
TWO TEMPERTURE - TWO HEATERS HIGH TEMPERATURE STORAGE
WITH OR WITHOUT RECIRCULATION
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
DANGER:
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
INSTALL THERMAL EXPANSION
TANK IN COLD WATER SUPPLY LINE,
IF CHECK VALVE OR PRESSURE
REDUCING VALVE IS USED IN
SUPPLY.
17
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