is not followed exactly, a re or explosion
may result causing property damage,
personal injury or death.
— Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
— WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do
not use any phone in your building.
• Immediately call your gas supplier
from a neighbor's phone. Follow the
gas supplier's instructions.
• If you cannot reach your gas supplier,
call the re department.
— Installatio n a n d service mu s t be
pe rfo rme d by a qualified installer,
service agency or the gas supplier.
500 Tennessee Waltz Parkway
Ashland City, TN 37015
www.hotwater.com
PLACE THESE INSTRUCTIONS ADJACENT TO BOILER AND
NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE
PRINTED 0210 317693-000
SAFE INSTALLATION, USE AND SERVICE
DANGER indicates an imminently
hazardous situation which, if not avoided,
will result in injury or death.
This is the safety alert symbol. It is used to alert you to
potential personal injury hazards. Obey all safety
messages that follow this symbol to avoid possible
injury or death.
WARNING indicates a potentially hazardous
situation which, if not avoided, could result
in injury or death.
CAUTION indicates a potentially hazardous
situation which, if not avoided, could result in
minor or moderate injury.
CAUTION used without the safety alert
symbol indicates a potentially hazardous
situation which, if not avoided, could result in
property damage.
WARNING
CAUTION
CAUTION
DANGER
The proper installation, use and servicing of this water heater is extremely important to your safety and the safety of others.
Many safety-related messages and instructions have been provided in this manual and on your own water heater to warn you and others
of a potential injury hazard. Read and obey all safety messages and instructions throughout this manual. It is very important that the
meaning of each safety message is understood by you and others who install, use, or service this water heater.
All safety messages will generally tell you about the type of hazard, what can happen if you do not follow the safety message, and how
to avoid the risk of injury.
The California Safe Drinking Water and Toxic Enforcement Act requires the Governor of California to publish a list of substances known to
the State of California to cause cancer, birth defects, or other reproductive harm, and requires businesses to warn of potential exposure
to such substances.
This product contains a chemical known to the State of California to cause cancer, birth defects, or other reproductive harm. This appliance
can cause low level exposure to some of the substances listed in the Act.
IMPORTANT DEFINITIONS
• Qualied Installer: A qualied installer must have ability equivalent to a licensed tradesman in the elds of plumbing,
air supply, venting and gas supply, including a thorough understanding of the requirements of the National Fuel Gas
Code or the Natural Gas and Propane Installation Code as it relates to the installation of gas red boilers. The qualied
installer must have a thorough understanding of this instruction manual.
• Service Agency: A service agency also must have ability equivalent to a licensed tradesman in the elds of plumbing,
air supply, venting and gas supply, including a thorough understanding of the requirements of the National Fuel Gas
Code as it relates to the installation of gas red boilers. The service agency must also have a thorough
understanding of this instruction manual, and be able to perform repairs strictly in accordance with the service guidelines
provided by the manufacturer.
• Gas Supplier: The Natural Gas or Propane Utility or service who supplies gas for utilization by the gas burning
appliances within this application. The gas supplier typically has responsibility for the inspection and code approval of
gas piping up to and including the Natural Gas meter or Propane storage tank of a building. Many gas suppliers also
offer service and inspection of appliances within the building.
2
GENERAL SAFETY
3
TABLE OF CONTENTS
SAFE INSTALLATION, USE AND SERVICE.......................................................................................................................................................................... 2
GENERAL SAFETY................................................................................................................................................................................................................ 3
TABLE OF CONTENTS .......................................................................................................................................................................................................... 4
DIMENSIONS AND CAPACITY DATA .................................................................................................................................................................................... 5
Correct Gas .................................................................................................................................................................................................................... 7
Liquid Petroleum Gas Models ........................................................................................................................................................................................ 7
High Altitude Installations ............................................................................................................................................................................................... 7
CONTROLS AND FUNCTION ................................................................................................................................................................................................ 8
High Limit ....................................................................................................................................................................................................................... 8
Intermittent Ignition Control Module ............................................................................................................................................................................... 8
Auto Reset High Limit Control ........................................................................................................................................................................................ 9
Tank Temperature Control .............................................................................................................................................................................................11
GENERAL ............................................................................................................................................................................................................................ 12
Air Requirements .......................................................................................................................................................................................................... 13
Chemical Vapor Corrosion............................................................................................................................................................................................ 13
System Connections .................................................................................................................................................................................................... 14
Venting the Boiler ......................................................................................................................................................................................................... 14
Venting System ............................................................................................................................................................................................................ 16
SYSTEM INSTALLATIONS .................................................................................................................................................................................................. 18
Linear Temp .......................................................................................................................................................................................................... 18
Water Supply Line ................................................................................................................................................................................................ 19
Expansion Tank .................................................................................................................................................................................................... 19
Gas Connections .......................................................................................................................................................................................................... 20
Gas Supply Line Purging and Sizing ............................................................................................................................................................................ 21
Gas Pressure Regulators ............................................................................................................................................................................................. 22
OPERATION AND START-UP INSTRUCTIONS .................................................................................................................................................................. 39
Important ...................................................................................................................................................................................................................... 39
Filling the System ......................................................................................................................................................................................................... 39
Pilot Alignment and Main Burner .......................................................................................................................................................................................... 39
REMOVAL OF EXISTING BOILER FROM A COMMON VENTING SYSTEM ..................................................................................................................... 45
GENERAL MAINTENANCE ................................................................................................................................................................................................. 45
Cleaning and Flushing Instructions ...................................................................................................................................................................................... 46
PRE TROUBLESHOOTING ................................................................................................................................................................................................. 46
EXTRA OPENING
FOR THERMOMETER
AND RELIEF VALVE
HW-520, 610
AND HW--670
TABLE 1
MODELS
DIMENSIONS IN INCHES
A Overall height65 (1651)57-1/8 (1451) 57-1/8 (1451) 68-5/16 (1735)67 (1702)64-3/4 (1645)
B Height to Top of Jacket43-1/4 (1099) 45-1/8 (1146) 45-1/8 (1146) 56-1/4 (1429) 56-1/4 (1429)56-1/4 (1429)
C Floor to Center Line Water Inlet36 (914)38-3/4 (984)38-3/4 (984)46 (1168)46 (1168)46 (1168)
D Diameter of Jacket25-1/4 (641)27 (686)27 (686)27 (686)27 (686)27 (686)
E Floor to Center Line Water Outlet12 (305)12 (305)12 (305)12 (305)12 (305)12 (305)
F Draft Diverter Outlet Diameter8 (203)10 (254)10 (254)10 (254)12 (305)12 (305)
G Floor to Center Line Gas Inlet16-1/2 (419)16-3/4 (425)16-3/4 (425)18 (457)18 (457)18 (457)
H Overall Depth29-5/8 (753)31-1/2 (800)31-1/2 (800)36-1/2 (927)36-1/2 (927)36-1/2 (927)
J Support Height9 (229)9 (229)9 (229)9 (229)9 (229)9 (229)
K Width of Control String (approx.)14 (356)14 (356)14 (356)11 (279)11 (279)11 (279)
L Pipe Size of Water Inlet (NPT)1-1/41-1/21-1/2222
M Pipe Size of Water Outlet (NPT)1-1/41-1/21-1/2222
N Pipe Size of Gas Inlet (NPT)3/411111
P Control String Plus 1/2 Jacket Diameter (approx.) 26-5/8 (676)27-1/2 (699)27-1/2 (699)24-1/2 (622)24-1/2 (622)24-1/2 (622)
S Horizontal Length between Water Inlet and Outlet5-3/8 (137)5-1/2 (140)5-1/2 (140)5-3/4 (146)5-3/4 (146)5-3/4 (146)
T Control String from Jacket5 (127)5 (127)5 (127)7 (178)7 (178)7 (178)
NOTE: All dimensions in inches (millimeters) except pipe size which is NPT
HW-300HW-399HW-420HW-520
PROPANE
HW-610/670
NATURAL
HW-610/670
5
TABLE 2, RECOVERY CAPACITIES
Input°F204050607080
Model
BTUH (kW)°C11.122.227.733.338.844.4
HW 300300,000 (88)
HW 399399,000 (117)
HW 420420,000 (123)
HW 520520,000 (152)
HW 610610,000 (179)
HW 670660,000 (193)
GPH1439719576480411360
LPH544827242179181615561362
GPH1914957765638547478
LPH724536232898241520701811
GPH20141007806671576504
LPH762738133051254221791907
GPH24941247998831713624
LPH944347213777314826982361
GPH292614631170975836731
LPH1107755384431369231652769
GPH3165158312661055904791
LPH1198559924794399534242996
COMPONENT LOCATION
FIGURE 1.
6
INTRODUCTION
This design complies with the current edition of the ANSI Z21.13
low-pressure boiler standard.
Compliance under this standard implies that when the boiler
underwent test, the gas manifold and control assembly pro vided
on the boiler met safe lighting and other performance criteria.
Detailed installation diagrams are found in this manual. These
diagrams will serve to provide the installer a reference for the
materials and methods of piping necessary. It is essential that
all water, gas piping and wiring be installed as shown on the
diagrams. You should thoroughly read and understand this manual
before installation and/or operation of this boiler.
The factory warranty will be void if the boiler(s) have been
improperly installed or operated.
In addition to these instructions, the boiler(s) shall be installed
in accordance with those installation regulations in force in the
local area where the installation is to be made. These shall be
carefully followed in all cases. Authorities having jurisdiction
should be consulted before installations are made.
In the absence of local codes, the installation must comply with the
current editions, as follows:
In the United States:
The National Fuel Gas Code, ANSI Z223.1/NFPA 54 and the
National Electric Code, NFPA 70.
In Canada:
Installation Code CAN/CSA B149.1 and Canadian Electrical Code,
CSA C22.1.
GROUNDING INSTRUCTIONS
IF THE BOILER HAS BEEN EXPOSED TO FLOODING, IT
MUST BE REPLACED.
LIQUEFIED PETROLEUM GAS MODELS
Boilers for propane or liquefied petroleum gas (LPG) are different
from natural gas models. A natural gas boiler will not function
safely on LP gas and no attempt should be made to convert a
boiler from natural gas to LP gas.
LP gas m ust be use d w i th g reat cau tion . I t is h ighl y
ex plo sive and h eavie r tha n air. It col lects f irs t in the low
ar eas m aki ng its odo r dif ficul t to det ect a t nose lev el.
If LP gas is prese nt or even sus pec ted, do not atte mpt
to fi nd the c aus e you rself . Lea ve the b uil ding, le avi ng
do ors open to ve nti late, t hen cal l your gas sup pli er o r
se rvi ce a gent. Kee p ar ea c lea r un til a se rvice cal l ha s
been made.
At ti mes you ma y not be ab le to smel l an LP gas leak.
On e c aus e is odor fad e, whic h i s a los s o f t he chemic al
od ora nt th at give s LP ga s its di stinc tiv e sme ll. An oth er
ca use can b e y our p hys ica l con dit ion, suc h a s hav ing
a c o ld o r d imin i shin g s ense o f smel l with a g e. F o r
the se r eas o ns, the u se o f a p rop a ne g as d etec tor i s
recommended.
IF YOU E XPE RIENC E AN OUT OF GAS S ITU ATION, D O
NO T T RY TO RELIGHT APP LIA NCES Y OUR SELF. Call
yo ur l oca l serv ice age nt. On ly t rained LP profe ssi ona ls
sh oul d co ndu ct t he r equ ired safety checks in accord anc e
with industry standards.
HIGH ALTITUDE INSTALLATIONS
This boiler must be grounded in accordance with the National Electrical
Code, Canadian Electrical Code and/or local codes. Correct wiring is
imperative for proper operation.
This boiler must be connected to a grounded metal, permanent
wiring system, or an equipment grounding conductor must be run
with the circuit conductors and connected to the equipment grounding
terminal or lead on the boiler.
CORRECT GAS
MAKE SURE THE GAS ON WHICH THE BOILER WILL
OPERATE IS THE SAME AS THAT SPECI FIED ON THE
BOILER RATING PLATE. DO NOT INSTALL THE BOILER IF
EQUIPPED FOR A DIFFERENT TYPE OF GAS — CONSULT
YOUR SUPPLIER.
PRECAUTIONS
IF THE UNIT IS EXPOSE D TO THE FOLLOWING, D O NO T
OPERATE UNTIL ALL CORRECTIVE S TE PS HAVE B EE N
MADE BY A QUALIFIED SERVICEMAN:
1. EXPOSURE TO FIRE.
2. IF DAMAGED.
3. FIRING WITHOUT WATER.
4. SOOTING.
Rated inputs are suitable up t o 2000 feet (61 0 m) elevation.
Co nsu lt the factory for i nst all ation a t alt itu des ove r 200 0
feet (610 m).
7
HIGH ALTITUDE INSTALLATIONS
IN CANADA
Acceptance of these models for use at altitudes above 2000 feet
(600 m) is based on eld test of the individual installation by the
provincial/state authority having jurisdiction.
IN THE U.S.A.
WARNING
INSTALLATIONS ABOVE 2000 FEET REQUIRE REPLACEMENT
OF THE BURNER ORIFICES IN ACCORDANCE WITH THE
CURRENT EDITION OF THE NATIONAL FUEL GAS CODE
(ANSI Z223.1). FAILURE TO REPLACE THE ORIFICES WILL
RESULT IN IMPROPER AND INEFFICIENT OPERATION OF THE
APPLIANCE RESULTING IN THE PRODUCTION OF INCREASED
LEVELS OF CARBON MONOXIDE GAS IN EXCESS OF SAFE
LIMITS WHICH COULD RESULT IN SERIOUS PERSONAL
INJURY OR DEATH.
For specic orice requirements, please refer to the appropriate
section of the National Fuel Gas Code ANSI Z223.1.
You should contact your gas supplier for any specic changes which
may be required in your area.
Ratings specified by manufacturers for most boilers apply for
elevations up to 2000 feet (600 m). For elevations above 2000 feet
(600 m) ratings must be reduced by a rate of 4% for each 1000 feet
(300 m) above sea level.
Example: If a boiler is rated at 610,000 Btu/hr. at sea level, to operate
the boiler at 5000 feet (1500 m) it must be derated by 20% (4% x 5)
to a new rating of 488,000 Btu/hr.
A. O. Smith does build some models specically for high altitude
service. Please check the rating plate before making changes.
The input reduction is primarily achieved by reducing the size
of the main burner orifices. To do this, the main burner orifices
re qui re repl aceme nt with orific es size d for the pa rticu lar
installation elevation. When ordering, be sure to state the model
number and the altitude of the location where the boiler is being
installed.
Upon field deration of the boiler, adjustment to the gas pressure
regulator is required. See CHECKING AND ADJUSTING
THE INPUT in this manual for inlet and manifold pressure
requirements. Also, due to the input rating reduction required at
high altitudes, the output rating of the appliance is also reduced
and should be compensated for in the sizing of the equipment
for applications.
CONTROLS AND FUNCTION
AUTO RESET HIGH LIMIT
Th e hig h l im it is a safety devic e w ired in s eries wit h t he
ignition system. Set the high limit control to approximately 10
ab ove the maxi mum d esigned system temper at ure. If th e
boi ler out let wa ter te mpe r atu re shou l d exc e ed the hig h
limit setting, the main gas valve will close but the circulator
will continue to operate. Maximum adjustable setting is 115
(239°F) cut-out with a 3
0
C (50F) to 250C (450F) adjustable
differential, see Figure 2.
FIGURE 2.
INTERMITTENT IGNITION CONTROL MODULE
The Honeywell S-8600 control module contains the electronic
components of the system and also serves as a control wiring system
for the controls mounted on the heater. The control module performs
the following functions:
0
F
0
C
3. Opens the pilot valve.
4. Discontinues ignition spark when the pilot flame is established.
The S-8600 control used on propane gas models provides
safety lockout if the pilot fails to ignite within the pilot flame
estab lishing period. The S-8600 control used on natural
gas models continues trial for ignition until pilot flame
is established.
5. After proof of pilot ame, opens then main valve.
6. On a power loss, shuts the heater down. When power is restored
it will begin a new ignition cycle.
7. On a loss of ame, shuts off main gas and starts trial for pilot ignition.
PLEASE SEE TROUBLESHOOTING SECTION FOR MORE
INFORMATION.
1. Checks for safe-start by sensing for a false ame condition on
start-up.
2. Generates a potential of 15,000 volts for spark ignition of the
pilot burner.
S-8600 INTERMITTENT IGNITION
CONTROL MODULE (IID)
FIGURE 3.
8
THERMAL BALANCER
Figure 4 shows the internal wiring of the thermal balancer. The
device may be tested after disconnecting the four leads from their
respective terminals on the unit.
1. Apply a test light to the yellow and red leads.
• The lamp should light as the contact in this circuit is normally
closed when the resistor is cool.
2. Apply a light to the black and yellow leads.
• The lamp should not light as the contact in this circuit is normally
open when the resistor is cool.
3. Remove the test light.
4. Apply 120 volts to the white and red leads which power the 1900
ohm resistor. After a warming period the contacts of the thermal
balancer should operate.
5. Remove the test light.
6. Apply the test light as described in steps 1 and 2.
While the resistor is still warm the lamp indications should be the
opposite as described previously.
FIGURE 4.
HIGH LIMIT SWITCH
FIGURE 5.
SAFETY FLOW SWITCH
The safety ow switch is a safety device which must be installed at
the water outlet of the unit to prevent main burner operation in the
event of inadequate water ow through the unit.
An accessory package containing a safety ow switch is available
for this application.
This switch may be mounted in a horizontal pipe line or a vertical
pipe line with upward water ow. Do not install the switch where the
water ow is downward.
For proper performance mount the switch in a section of pipe where
there is a straight run of at least 5 pipe diameters on each side of the ow
switch (i.e. do not locate adjacent to valves, elbows, orices, etc.).
The ow switch shall be mounted in a standard 1-1/2" x 1-1/2" x 1"
tee for a 1-1/2" pipe application. For larger pipe sizes use a reducing
tee in order to keep the switch as close to the pipe as possible. Install
the ow switch in the branch (top) opening of the reducing tee and
provide adequate paddle length in the ow stream. For example in
a 2" pipe installation use a 2" x 2" x 1" reducing tee. For 2", or 3"
pipe use paddle segments as supplied. For other pipe sizes (i.e.
1-1/4", 1-1/2" and 2-1/2") trim the paddle to the proper pipe size, see
Figure 6 on page 10. If a standard tee is used, install a face or hex
bushing in the top opening. The paddle must be adjusted or trimmed
to the size of the pipe in which it will be installed.
MANUAL RESET HIGH LIMIT
This boiler is equipped with a manual reset high limit switch,
located under the small cover on the side of the jacket, see
Fi gur e 5. T his devi ce p rov ide s posi tiv e s hut dow n of the
boiler in the event of boiler or system malfunction. Should the
surface temperatu re of the copper t ubing hea t exc ha nger
rea ch 25 0 °F (12 0°C), th e h i gh li mit sw itc h will ac tiv ate ,
the gas valve will c lose, the pilot and main burners will be
extinguished. If the high limi t switch should shut of f unit, check
the following conditions:
• No water in boiler.
• Restricted water flow through the boiler.
• Improper wiring (boiler firing without circulator
operating).
• Pump failure.
After correcting failure condition remove the protector switch cover
and push the reset button. The high limit switch may be reset after
the coil surface cools to 6°F (3.3°C) below the trip setting.
CAUTION
Any part of the paddle must not touch the pipe or any restrictions in
the pipe. Screw the ow switch in position so the at of the paddle
is at right angles to the ow. The arrow on the side case must point
in the direction of the ow.
TABLE 3 - SAFETY FLOW SWITCH
Minimum Pipe Rate
Model Number
Contacts Closed
(Flow)
Contacts Open
(No Flow)
GPMLPMGPMLPM
HW-3005.822.03.714.0
HW-3997.528.45.018.9
HW-4207.528.45.018.9
HW-52013.751.99.536.0
HW-610/67013.751.99.536.0
The safety ow switch may be eld adjusted to obtain higher
minimum ow rates than those shown in table 3.
9
To adjust the ow rate setting:
1. Remove the ow switch cover.
2. For higher ow rate - turn the range adjusting screw clockwise.
CAUTION
The switch is factory set at approximately the minimum ow rate, see
Table 3 on page 9. It must not be set lower than the factory setting as
this may result in the switch failing to return at 'no ow' condition.
3. For lowe r flow rat e - tur n the rang e adjus tin g sc rew
counterclockwise.
CAUTION
Paddle must be trimmed at the dotted arc. It must not touch the pipe or have any restriction when installed.
4. Replace ow switch cover. Where units are installed in multiples,
each boiler must be individually protected by a safety ow switch.
FIGURE 6.
SAFETY RELIEF VALVES
Your local code authority may have other specic relief valve
requirements not covered below.
WARNING
THE PURPOSE OF A SAFETY RELIEF VALVE IS TO AVOID
EXCESSIVE PRESSURE OR TEMPERATURE INTO THE STEAM
RANGE WHICH MAY CAUSE SCALDING AT FIXTURES, TANK
EXPLOSION, SYSTEM OR BOILER 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 BOILER AND THE
RELIEF VALVE OR THE RELIEF VALVE AND THE DRAIN 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.
If any safety relief valve is replaced, the replacement valve must comply
with the current editions of the ASME Boiler and Pressure Vessel
10
Code, Section IV or CSA B51, as applicable. Select a relief valve with
a discharge NOT less than the boiler input, and a pressure rating NOT
exceeding the working pressure of any component in the system.
A. O. Smith supplies a 125 psi relief valve for hot water supply systems
and 50 psi relief valve for space heating application.
An ASME rated temperature and pressure relief valve must be installed
on each and every water storage tank in a hot water supply system.
The storage tank temperature and pressure (T & P) relief valve must
comply with the applicable contruction provisions of the Standard
for Relief valves and Automatic Gas Shutoff Devices for Hot Water
Supply Systems, Z21.22 - CSA 4.4. The T & P valve must be of the
automatic reset type and not embody a single-use type of fusible
plug, cartridge or linkage.
The T & P relief valve should have a maximum temperature rating
of 100°C (210°F), 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 boilers supplying
water to the storage tank.
Locate the T & P relief valve (a) in the top of the storage tank or (b)
in the side of the tank on centerline within upper 6 inches from the
top of the tank. See Figures 28 to 33, Pages 34 to 38. Tapping shall
be threaded in accordance with the latest version of the Standard for
Pipe Threads, General Purpose (inch), ANSI/ASME B.120.1.
TANK TEMPERATURE CONTROL
The water temperature in the storage tank is controlled by the Tank
Temperature Control. The sensing element is mounted inside the
hot water storage tank.
DANGER
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 PERSON’S 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.
Mark location with a class III Label. See ANSI Z21.10.1, Part 1,
Marking, See CAN/CSA B149.
The tank temperature control is adjustable from 100°F (37.7°C) to
220°F (104.4°C). It is recommended that lower water temperatures
be used to avoid the risk of scalding. It is further recommended, in all
cases, that the water temperature be set for the lowest temperature
which satises the user’s hot water needs. This will also provide the
most energy efcient operation of the water heater and minimize
scale formation.
THE WATER HEATER SHOULD BE LOCATED IN AN AREA WHERE
THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO SET
TEMPERATURES. SETTING THE WATER TEMPERATURE AT
120°F (49°C) WILL REDUCE THE RISK OF SCALDS. Some states or
provinces require settings at specic lower temperatures. Below you
will nd listed the approximate time-to-burn relationship for normal
adult skin. 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.
USE ANTI-SCALD VALVE(S) in the hot water system to reduce
the risks of scalds at points of use such as lavatories, sinks
and bathing facilities.
A change in water temperature in the storage tank lower than
the Tank Temperature Control setting will c ause the sensor to
close its contacts and consequently energize the boiler.
If the Tank Temperature Control is out of calibration, replace it
with a new one; do not attempt to fix this control.
SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL
TO SHUT OFF, TURN O FF THE MANUAL G AS CONTROL
VALVE TO THE APPLIANCE.
Time to Produce 2nd & 3rd
Degree Burns on Adult Skin
Nearly Instantaneous
About 1/2 second
About 1-1/2 seconds
Less than 5 seconds
About 30 seconds
More than 5 minutes
WARNING
THERMOMETERS
Thermometers should be obtained and field installed as shown
in the installation diagrams.
The rmom e ter s are ins tall e d in th e sys tem a s a mea n s
of de t e ctin g a p ossi b l e limi n g condi t i on in t h e boile r.
An incr ease of 5°F (3°C ) ov er the norma l te m per a tur e
rise t h r o u g h t h e boiler i s a n i n d i c a t i o n t h a t l i m e i s
p r e sen t . T he t e r m " t emp e rat u r e r ise " d es ign a t es
the diff ere nce be twe en the boil er inle t and ou tle t wate r
temperature.
An inc rease of 5°F (3°C) above the rec orded temperature
rise may signi f y a li ming con diti o n in the coil s or he at
e x c ha n ge r . R e fe r t o C L E A NI N G A N D F L US H IN G
section of this manual for deliming instructions.
Rec o r d temperature rise at i n i t i a l st a r t - up f o r future
reference.
DRAIN VALVE (Not Supplied)
A drain valve must be obtained and installed on each boiler
and tank for draining purposes, see installation diagrams in
this manual.
GENERAL
REQUIRED ABILITY
Installation or service of this boiler requires ability equivalent to that
of a licensed tradesman in the eld involved. Plumbing, air supply,
venting, gas supply and electrical work are required.
LOCATION
When installing the boiler, consideration must be given to proper
location. Location selected should be as close to the stack or chimney
as practicable with adequate air supply and as centralized with the
piping system as possible. This location should also be such that the
gas ignition system components are protected from water (dripping,
spraying, etc.) during appliance operation and service (circulator
replacement, control replacement, etc.).
THE BOILER MUST NOT BE INSTALLED ON CARPETING.
THE BOILER SHOULD NOT BE LOCATED IN AN AREA WHERE
IT WILL BE SUBJECT TO FREEZING.
LOCATE IT NEAR A FLOOR DRAIN. THE BOILER SHOULD BE
LOCATED IN AN AREA WHERE LEAKAGE FROM THE BOILER OR
CONNECTIONS WILL NOT RESULT IN DAMAGE TO THE ADJACENT
AREA OR TO LOWER FLOORS OF THE STRUCTURE.
WHEN SUCH LOCATIONS CANNOT BE AVOIDED, A METAL
DRAIN PAN SHOULD BE INSTALLED UNDER THE BOILER. Such
pans should be fabricated with sides at least 60mm (2-1/2") deep,
with length and width at least 50mm (2") greater than the diameter
of the boiler and must be piped to an adequate drain. The pan must
not restrict combustion air ow.
WARNING
KEEPING BOILER AREA CLEAR AND FREE FROM COMBUSTIBLE
MATERIALS, GASOLINE AND OTHER FLAMMABLE VAPORS AND
LIQUIDS.
WARNING
THERE IS A RISK IN USING FUEL BURNING APPLIANCES
SUCH AS BOILERS IN ROOMS OR AREAS WHERE GASOLINE,
OTHER FLAMMABLE LIQUIDS OR ENGINE DRIVEN EQUIPMENT
OR VEHICLES ARE STORED, OPERATED OR REPAIRED.
FLAMMABLE VAPORS ARE HEAVY AND TRAVEL ALONG THE
FLOOR AND MAY BE IGNITED BY THE IGNITER OR MAIN BURNER
FLAMES CAUSING FIRE OR EXPLOSION. SOME LOCAL CODES
12
PERMIT OPERATION OF GAS APPLIANCES IF INSTALLED
18 INCHES OR MORE ABOVE THE FLOOR. THIS MAY
REDUCE THE RISK IF LOCATION IN SUCH AN AREA CANNOT
BE AVOIDED.
WARNING
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST
NEVER BE PLACED ON OR ADJACENT TO THE BOILER.
OPEN CONTAINERS OF FLAMMABLE MATERIAL MUST
NOT BE STORED OR USED IN THE SAME ROO M WITH
THE BOILER.
A hot water boiler installed above radiation level or as required
by the authority having jurisdiction, must be provided with a low
water cutoff device at the time of boiler installation.
AIR REQUIREMENTS
Provisions for combustion and ventilation air in accordance
w i t h t h e c u r ren t e d iti o n o f t h e N a ti ona l F u el G as
C o d e , A NS I Z 2 2 3. 1, C A N / CS A B 1 4 9 .1 , I n st alla t i o n
C o d e s , o r a p p l i c a b l e p r o v i s i o n s o f t h e l o c a l
building codes.
Provisions for vent, bleed and gas relief lines (when applicable).
Keep appliance area free of combustible or ammable liquids.
If the confined space is within a building of tight construction,
air for combustion, ventilation, and draft hood dilution must be
obtained from outdoors. When directly communicating with the
outdoors or communicating with the outdoors through vertical
ducts, two permanent openings, located in the above manner,
shall be provided. Each opening shall have a free area of not
less than one square inch per 4000 Btuh of the total input of
all appliances in the enclosure. If horizontal ducts are used,
each o pe ni ng shall h ave a free area of not less tha n one
square inch per 2000 Btuh of the total input of all appliances
in the enclosure.
(b) Canadian Installations
Ventilation of the space occupied by the b oiler(s) shall be
provided by an opening for ventilation air at the highest practical
point communicating with outdoors. The total cross-sectional
area shall be at least 10% of the area of the combustion air
opening but in no case shall the cross-sectional area be less
than 10 square inches (6500 mm
2
).
In additional to the above, there shall be permanent air supply
opening(s) having a cross-sectional area of not less than 1
square inch per 7,000 BTUH (310 mm
2
/KW) up to and including
1,000,000 BTUH plus 1 square inch per 14,000 BTU in excess
of 1,000,000 BTUH. This opening(s) shall be located at, or
ducted to, a point neither more than 18" (450 mm) nor less
than 6 inches (150 mm) above the floor level.
Do not obstruct the ow of combustion or ventilating air.
WARNING
FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR
COMBUSTION AND VENTILATION. AN INSUFFICIENT SUPPLY
OF AIR WILL CAUSE RECIRCULATION OF COMBUSTION
PRODUCTS RESULTING IN AIR CONTAMINATION THAT
MAY BE HAZARDOUS TO LIFE. SUCH A CONDITION OFTEN
WILL RESULT IN A YELLOW, LUMINOUS BURNER FLAME,
CAUSING CARBONING OR SOOTING OF THE COMBUSTION
CHAMBER, BURNERS AND FLUE TUBES AND CREATES A
RISK OF ASPHYXIATION.
Unconned Space
In buildings of conventional frame, brick or stone construction,
unconned spaces may provide adequate air for combustion, and
draft hood dilution.
If the unconfined space is within a building of tight construction
(buildings using the following construction: weather stripping,
heavy insulation, caulking, vapor barrier, etc.) air for combustion,
ventilation, and draft hood dilut io n must be obt ained from
outdoors or spaces freely communicating with the outdoors. The
installation instructions for confined spaces in tightly constructed
buildings must be followed to ensure adequate air supply.
Conned Space
(a) U. S. Installations
When drawing combustion and dilution air from inside a conventionally
constructed building to a conned space, such a space shall be
provided with two permanent openings, ONE WITHIN 12 INCHES
OF THE ENCLOSURE TOP AND ONE WITHIN 12 INCHES OF THE
ENCLOSURE BOTTOM. Each opening shall have a free area of at
least one square inch per 1000 Btuh of the total input of all appliances
in the enclosure, but not less than 100 square inches.
Where power vented equipment is used in the same room as the
boiler, sufcient air openings must be supplied.
UNDERSIZED OPENINGS MAY RESULT IN INSUFFICIENT AIR
FOR COMBUSTION.
WHERE AN EXHAUST FAN IS INSTALLED IN THE SAME ROOM
WITH A BOILER, SUFFICIENT OPENINGS FOR AIR MUST BE
PROVIDED IN THE WALLS.
UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN
INTO THE ROOM THROUGH THE CHIMNEY, CAUSING POOR
COMBUSTION. SOOTING MAY RESULT WITH AN INCREASED
RISK O F ASPHYXIATION.
CHEMICAL VAPOR CORROSION
WARNING
CORROSION O F T H E FLUE W AY S A N D VENT SYSTEM
MAY OCCUR IF AIR FOR COMBUSTION CONTAINS
C E R TA I N C H E M I C A L V A P O R S W H I C H B R E A K
DOWN IN TO A C I D S AT HIGH T E M P E R AT U R E . SUCH
CORROSION M AY R E S U LT I N FA I L U R E A N D R I SK OF
ASPHYXIATION.
Water boiler corrosion and component failure can be caused
by the heating and breakdown of airborne chemical vapors.
Spray can propellants, cleaning solvents, refrigerator and air
conditioning refrigerants, swimming pool chemicals, calcium
and sodium chloride, waxes, and process chemicals are typical
compounds which are corrosive. These materials are corrosive
at very low concentration levels with little or no odor to reveal
their presence. Products of this sort must not be stored near
the boiler. Also, air which is brought in contact with the water
boiler should not contain any of these chemicals. If necessary,
uncontaminated air should be obtained from remote or outside
sources.
13
INSTALLATION CLEARANCES
These boilers are approved for installation on combustible ooring
in an alcove with minimum clearance to combustibles of:
Sufcient area should be provided at the front and rear of the unit
for proper servicing. Clearances of 24 inches (609.4mm) in the
rear and 48 inches (1,219mm) in the front are required by code.
In a utility room installation, the door shall be wide enough to allow
the boiler to enter or to permit the replacement of another appliance
such as a water heater.
LEVELING
Each unit should be checked after installation to be certain that it is level.
If the unit is not level, insert metal shims under the legs of the unit
to correct this condition.
Two inch (50.8mm) clearance is allowable from combustible
construction for hot water pipes.
SYSTEM CONNECTIONS
The system installatio n must conform to these instructions
and to the requirements of the local code authority having
jurisdiction. Good practice requires that all heavy piping be
supported.
A TYPICAL BOILER INSTALLATION
FIGURE 7.
VENTING
VENTING THE BOILER - STANDARD VENTING
WARNING
THE INS T RUCT I ONS IN THIS SE CTIO N ON VEN TING
TH E BOILER M UST BE FOLLOWED TO AVOI D CHOK ED
COM B UST ION OR RECI RCU L AT ION OF FLUE GA SES .
SUCH CONDITIONS CAUSE SOOTING OR RISKS OF FIRE
AND ASPHYXIATION.
TYPE B VENTING MAY BE USED WITH THESE BOILERS. ALL
LOCAL UTILITY REGULATIONS ON VENTING SHOULD BE
FOLLOWED.
For boilers for connection to gas vents or chimneys, vent sizing,
installation and termination shall be in accordance with the
current edition of the National Fuel Gas Code, ANSI Z223.1, or
CAN/CSA B149.1, Installation Codes, or applicable provisions
of the local building codes.
Vent connectors serving appliances vented by natural draft shall
not be connected into any portion of mechanical draft systems
operating under positive pressure.
The minimum distance from adjacent public walkways, adjacent
buildings, openable windows and building openings shall not be
less than those values specif ied in the National Fuel Gas Code,
ANSI Z223.1 and/or CAN/CSA B149.1, Installation Codes;
Stack or chimney must be a minimum height of 12 " (305mm)
above the annual snow fall to prevent blockage.
14
Building materials must not come in contact with combustion
products from stack or chimney, due to the degradating properties
of ue products.
Vent connectors serving appliances vented by natural draft shall not
be connected into any portion of mechanical draft systems operating
under positive pressure.
Flue products must have a minimum clearance of 4 feet (1.22m)
horizontally from, and in no case above or below, unless a 4-foot
(1.22m) horizontal distance is maintained, from electric meters, gas
meters, regulators and relief equipment.
CAN/CSA B149.1, Installation Code species a 6 foot horizontal
vent terminal clearance to gas and electric meters and relief devices
(this clearance is specied as 4 feet in the U.S. under the National
Fuel Gas Code, ANSI/Z223.1). Therefore instruction, which species
compliance with the 4 foot clearance, as applies in the U.S. only, and the
CAN/CSA B149.1 Installation Code applies in Canada.
1. DRAFT HOOD
The draft hood furnished with this boiler must be installed without
alteration. Provision must be made if the boiler is installed in conned
space or a small boiler room to accommodate draft hood spillage and
avoid risks described above. The upper air opening called for in the
AIR REQUIREMENTS section of this manual is for this purpose.
2. VENT CONNECTION
Size and install proper size vent pipe. Do not reduce pipe size to
less than that of the draft hood outlet.
Horizontal runs of vent pipe shall be securely supported by
adequately placed (approximately every 4 feet or 1 meter), noncombustible hanger s and /or slip joints suitable for the weight
and design of the materials employed to prevent sagging and
to maintain a minimum upward slope of 1/4" (21mm/m) per foot
from the boiler to the vent terminals, see Figure 8. Dampers or
other obstructions must not be installed in the vent. Be sure
that the vent pipe does not extend beyond t he inside wall of
the chimney.
3. CONNECTING BOILER TO A COMMON VENT
Do not connect the boiler to a common vent or chimney with solid
fuel burning equipment. This practice is prohibited by many local
building codes as is the practice of venting gas red equipment to
the duct work of ventilation systems.
Where a separate vent connection is not available and the vent pipe
from the boiler must be connected to a common vent with oil burning
equipment, the vent pipe should enter the common vent or chimney
at a point ABOVE the ue pipe from the oil red unit.
Where two or more appliances vent into a common vent connector
or manifold, the area of the common vent or vent connector should
at least equal the area of the largest vent connector plus 50% of the
areas of the additional draft hood outlets.
When removing a boiler from a system with a common vent, use
the following steps:
Be sure the other appliances connected to the common vent are
not in operation.
Seal any unused openings in the common venting system.
Visually inspect the venting system for proper size and horizontal pitch
and determine there is no blockage or restriction, leakage, corrosion
and other deciencies which could cause an unsafe condition.
WARNING
Ensure sufcient supply and ventilation air. Under no circumstances
should the equipment room where the boiler is installed ever be under
negative pressure. Insufcient air supply can interfere with combustion
and ventilation of this boiler resulting in unsafe conditions.
VENT PIPE INSTALLATION
FIGURE 8.
Where a continuous or intermittent back draft is found to exist the
cause must be determined and corrected. A special vent cap may
be required. If the back draft cannot be corrected by the normal
methods or if a suitable draft cannot be obtained, a blower type
ue gas exhauster may be employed to ensure proper venting and
correct combustion if permitted by local codes.
WARNING
FAIL URE TO CORRECT BACK DRAFTS WILL CAUSE AIR
CONTAMINATION AND UNSAFE CONDITIONS.
Insofar as is practical, close all building doors and windows and
all doors between the space in which the appliances remaining
connected to the common venting system are located and other
spaces of the building. Turn on clothes dryers and any appliance not
connected to the common venting system. Turn on any exhaust fans,
such as range hoods and bathroom exhausts, so they will operate
at maximum speed. Close replace dampers.
Place in operation the appliance being inspected. Follow the
lighting instructions. Adjust thermostat so appliance will operate
continuously.
Test for spillage at the draft hood relief opening after ve minutes of
main burner operation. Use the ame of a match or candle.
After it has been determined that each appliance remaining connected
to the common venting system properly vents when tested as outlined
above, return doors, windows, exhaust fans, replace dampers and
any other gas burning appliance to their previous conditions of use.
Any improper operation of the common venting system should be
corrected so the installation conforms with the current edition of
CAN/CSA B149.1 (current edition). When resizing any portion of
the common venting system, the common venting system should
be resized to approach the minimum size as determined using the
appropriate tables in CAN/CSA B149.1.
15
4. MULTIPLE VENT TABLE
Table 5 on page 17 has been compiled to show the material
sizes in a Type B doublewall combined vent system. Refer to
CAN/CSA B149 .1 (current edition), or the ASHRAE 1983 Equipment
Volume for further information.
A combined vent system is one in which two or more boilers at one
level are attached to a common vent.
In order to use table 5, the connector rise and total vent height must
be known. Connector rise is vertical distance from the draft hood outlet
to the point where the manifold connection is made. Total vent height
is the least vertical distance from a draft hood outlet to the top of the
vent. Local codes or utility requirements often govern termination
height. ULC listed doublewall gas vents, up through 24" (610mm)
diameter, can be installed in heated and unheated areas and can
pass through oors, ceilings, partitions, walls and roofs, provided
the required one inch clearance is observed. These vents should be
installed in accordance with CAN/CSA B149.1 (current edition).
EXAMPLE SHOWING USE OF THE HW-610 COMBINED VENT
SIZING TABLE
1. Turn off the electrical power (main manual gas shutoff and pilot
valves, if applicable).
Allow boiler parts and vent to cool before disassembly.
2. Remove the boiler draft diverter and vent pipe running to the chimney.
• Check parts and chimney for obstructions and clean as necessary.
3. Remove burner from boiler and other metal parts as required to
clean and vacuum the heat exchanger and combustion coils.
• Refer to parts list supplied with this manual for disassembly aid.
4. Reinstall the parts removed in steps 2 and 3.
• Be sure the vent pipe has a minimum upward pitch of one quarter
inch per foot of length (21mm/m) and is sealed as necessary.
5. Restore electrical power and gas supply to boiler.
• Place boiler in operation by following the lighting instructions
in this manual.
• Check for gas leaks and proper boiler and vent operation.
VENTING - SIDEWALL (OPTIONAL) POWER VENT SYSTEM
If you are installing the optional Power Vent Kit, refer to your
HW Power Vent Kit Installation Instructions for proper wiring
and installation procedures. Contact your local A. O. Smith
representative for details.
FIGURE 9.
VENTING MAINTENANCE - STANDARD VENTING
It is recommended that the heating surfaces and vent piping of
the appliance be checked every six months for dust, deterioration
and carbon deposits. Remove all soot or other obstructions from
chimney and ue which will retard free draft. Replace any damaged
or deteriorated parts of the venting system.
VENTING SYSTEM
HAVE VENTING SYSTEM CHECKED EVERY SIX MONTHS FOR
OBSTRUCTIONS AND/OR DETERIORATION IN VENT PIPING.
A. Insofar as is practical, close all doors, windows and air inlets to
the building. Turn on all exhaust fans (range hood, bathroom
exhaust, etc.) so they will operate at their maximum speed.
Close replace dampers.
B. After allowing appliance to operate for ve minutes, test for
spillage at the draft hood relief opening.
C. “CHECKING THE DRAFT. Operate vent connected gas utilization
equipment for several minutes and check to see that the combustion
products are going up the chimney or gas vent properly by passing
a lighted match or taper around the edge of the relief opening of
the draft hood. If the chimney or gas vent is drawing properly, the
match ame will be drawn into the draft hood. If not, the combustion
products will tend to extinguish this ame. IF THE COMBUSTION
PRODUCTS ARE ESCAPING FROM THE RELIEF OPENING OF
THE DRAFT HOOD, DO NOT OPERATE THE EQUIPMENT UNTIL
PROPER ADJUSTMENT OR REPAIRS ARE MADE TO PROVIDE
ADEQUATE DRAFT THROUGH THE CHIMNEY OR GAS VENT.”
D. Next, turn on all other fuel burning appliances within the same
room so they will operate at their full input.
Qualied servicers should follow this procedure when the boiler’s
external heating surfaces and vent pipe need cleaning.
CAUTION
DO NOT USE A NYLON BRUSH OR OTHER STATIC CREATING
MATERIAL TO CLEAN DUST AND CARBON DEPOSITS FROM
HEATING SURFACES AND VENT.
SUCH DEPOSITS ARE FLAMMABLE AND MAY BE IGNITED BY
STATIC ELECTRICITY. USE A METAL BRUSH TO MINIMIZE THE
DANGER OF EXPLOSION.
Repeat step C above, checking the draft on each appliance.
Total Vent Height (Measured in Feet Above Draft Hood)
1015203040506080100
Total Vent Height (Measured in Feet Above Draft Hood)
1015203040506080100
Connector Diameter (in Inches)
Manifold and Common Vent Diameter (in Inches)
Known: (5) model HW-610 boilers. (See illustration).
Connector rise - 2' (Note 1' is minimum). Total vent
height 30'.
Problem: Determine diameter of connector, manifold and
common vent.
Procedure: Enter the top of the HW-610 table (total vent height)
at 30' and the side at 2' (connector rise). A 14"
connector diameter is indicated for each connector
rise.
To determine the manifold and common vent size, enter table on this
page (total vent height) at 30 and the side at 5 boilers. A manifold
diameter of 24" (610 mm) is indicated.
17
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