A.O. Smith HW-300, HW-520, HWB-610, HWB-420, HW-420 User Manual

...

MODELS HW/HWB 300, 399, 420, 520, 610, 670

GAS-FIRED COMMERCIAL COPPER BOILERS FOR

HYDRONIC HEA TING AND HOT W A TER SUPPL Y

UP-FLOW MODELS

• INSTALLATION • OPERATION • MAINTENANCE • LIMITED WARRANTY

• INDOOR ONLY

WARNING: If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury or death.

— Do not store or use gasoline or other

flammable vapors and liquids in the vicinity of this or any other appliance.

— WHAT TO DO IF YOU SMELL GAS

• Do not try to light any appliance.

• Do not touch any electrical switch; do not use any phone in your building.

• Immediately call your gas supplier

TEXT PRINTED OR OUTLINED IN RED CONT AINS INFORMATION RELATIVE TO YOUR SAFETY. PLEASE READ THOROUGHLY BEFORE USING APPLIANCE.

CAUTION

from a neighbor's phone. Follow the gas supplier's instructions.

• If you cannot reach your gas supplier, call the fire department.

— Installation and service must be

performed by a qualified installer, service agency or the gas supplier.

PLACE THESE INSTRUCTIONS ADJACENT TO BOILER AND

NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE

PRINTED IN U.S.A. 0905 SUPERSEDES PART NO'S, 210288-000 REV. 01 & 192356-000

A DIVISION OF A.O. SMITH CORPORATION

MC BEE, SC SEATTLE, W A

STRATFORD, ONT ARIO

VELDHOVEN, THE NETHERLANDS

www.hotwater.com

PART NO. 211683-000 REV.02

ROUGH-IN DIMENSIONS

HW/HWB-610

AND HW-670

NA TURAL GAS ONL Y

EXTRA OPENING FOR THERMOMETER AND RELIEF VALVE HW/HWB-520, 610 AND HW--670

TABLE 1 MODELS

Prop. Nat.

DIMENSIONS IN INCHES

HWB/ HWB/ HWB/ HWB/ HWB/ HWB/

HW-300 HW-399 HW-420 HW-520 HW-610/670 HW-610/670

A Overall height 65 (1651) 57-1/8 (1451) 57-1/8 (1451) 68-5/16 (1735) 67 (1702) 64-3/4 (1645) B Height to top of jacket 43-1/4 (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 inlet 36 (914) 38-3/4 (984) 38-3/4 (984) 46 (1168) 46 (1168) 46 (1168) D Diameter of jacket 25-1/4 (641) 27 (686) 27 (686) 27 (686) 27 (686) 27 (686)

E Floor to center line water outlet 12 (305) 12 (305) 12 (305) 12 (305) 12 (305) 12 (305)

F Draft diverter outlet diameter 8 (203) 10 (254) 10 (254) 10 (254) 12 (305) 12 (305) G Floor to center line gas inlet 16-1/2 (419) 16-3/4 (425) 16-3/4 (425) 18 (457) 18 (457) 18 (457) H Overall depth 29-5/8 (753) 31-1/2 (800) 31-1/2 (800) 36-1/2 (927) 36-1/2 (927) 36-1/2 (927)

J Support height 9 (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) 1-1/4 1-1/2 1-1/2 2 2 2

M Pipe size of water outlet(NPT) 1-1/4 1-1/2 1-1/2 2 2 2

N Pipe size of gas inlet (NPT) 3/4 1 1 1 1 1 P Control string plus 1/2 jacket dia. (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) Q Water outlet to jacket 1 (25) 1 (25) 1 (25) 3-1/2 (89) 3-1/2 (89) 3-1/2 (89) R Water inlet casting to center line of jacket 10-1/8 (257) 11-1/4 (286) 11-1/4 (286) 12 (305) 12 (305) 12 (305) S Horizontal length between water inlet and outlet 5-3/8 (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 jacket 5 (127) 5 (127) 5 (127) 7 (178) 7 (178) 7 (178)

Approx. shipping weight lbs. (Kilograms) 240 (109) 291 (132) 291 (132) 361 (164) 361 (164) 361 (164)

NOTE: All dimensions in inches (millimeters) except pipe size which is NPT.

TABLE 2, SPECIFICATIONS - CANADIAN MODELS ONLY

Maximum

Maximum I.A.S. Maximum Max. Heat Transfer Max. Heat Transfer

Model Type of Gas BTUH(KW) BTUH(KW) Heat Loss Load Surface Area (Sq. Ft.) Surface Area (Sq. Ft.)

HWB-300 Natural & Propane 300,000 (88) 247,200 (72) 210,120 (62) 1,410 (.41) 1,051 (.31) HWB-399 Natural & Propane 399,000 (116) 322,790 (95) 274,371 (80) 1,829 (.54) 1,372 (.40) HWB-420 Natural & Propane 420,000 (123) 344,400 (101) 292,740 (86) 1.952 (57) 1,464 (.43) HWB-520 Natural & Propane 520,000 (152) 429,000 (126) 364,650 (107) 2,431 (.71) 1,823 (.53) HWB-610 Natural 610,000 (179) 502,600 (147) 427,210 (125) 2,848 (.83) 2,136 (.61) HWB-610 Propane 610,000 (179) 488,000 (143) 414,800 (121) 2,765 (.81) 2,074 (.61)

Ratings shown are for current modern heating system design. Where A.O. Smith boilers are connected to heavy, cast iron radiator systems or where unusual pick-up or large size piping conditions exist, reduce ratings by 10%.

NOTE: To compensate for the effects of high altitude areas above 2000 feet, the input, output and heating load ratings should be reduced approximately 4% for each 1000 feet above sea level.

TABLE 3, RECOVERY CAPACITIES - CANADIAN MODELS ONLY

Model (Btu/Hr.) Rise (F) 20 30 40 50 60 70 80 90 100 110 120 130 140

HW-300 300,000 LPH 5,505 3,670 2,753 2,202 1,835 1,573 1,376 1,223 1,001 1,001 918 847 786 HW-399 399,000 LPH 7,322 4,882 3,661 2,929 2,441 2,092 1,831 1,627 1,464 1,331 1,220 1,127 1,046 HW-420 420,000 LPH 7,708 5,138 3,854 3,083 2,569 2,202 1,927 1,713 1,542 1,401 1,285 1,186 1,101 HW-520 520,000 LPH 9,543 6,362 4,771 3,817 3,181 2,727 2,386 2,121 1,909 1,735 1,590 1,468 1,363 HW-610 610,000 LPH 11,194 7,463 5,597 4,478 3,731 3,198 2,799 2,488 2,239 2,035 1,866 1,722 1,599

Input Temp. (C) 11 17 22 26 33 39 44 50 56 61 67 72 78

GPH 1,455 970 727 582 485 416 364 323 291 264 242 224 208 GPH 1,935 1,290 967 774 645 553 484 430 387 352 322 298 276 GPH 2,036 1,358 1,018 815 679 582 509 453 407 370 339 313 291 GPH 2,521 1,681 1,261 1,008 840 720 630 560 504 458 420 388 360 GPH 2,958 1,972 1,479 1,183 986 845 739 657 592 538 493 455 423

FOREWORD

CAUTION

TEXT PRINTED OR OUTLINED IN RED CONT AINS INFORMATION RELA TIVE TO YOUR SAFETY. PLEASE READ THOROUGHLY BEFORE USING APPLIANCE.

Detailed installation diagrams are in this manual. These diagrams will serve to provide the installer with a reference for the materials and method of piping suggested. IT IS NECESSARY THA T ALL W ATER AND GAS PIPING AND THE ELECTRICAL WIRING BE INST ALLED AND CONNECTED AS SHOWN IN THE DIAGRAMS.

CHECK THE DIAGRAMS THOROUGHL Y BEFORE STARTING INSTALLA TION TO A VOID POSSIBLE ERRORS AND TO MINIMIZE TIME AND MATERIALS COST .

This design complies with the latest edition of ANSI Z21.13. CSA 4.9 low-pressure boiler .

Particular attention should be given to the installation of thermometers at

TABLE OF CONTENTS

PAGE

ROUGH-IN DIMENSIONS ................................................................... 2-3

FOREWORD ...................................................................................... 4

INSTALLA TION INSTRUCTIONS ........................................................ 4

Required Ability .......................................................................... 4

Installation As Boiler Replacement ............................................. 4

Location ...................................................................................... 5

Air Requirements........................................................................ 5-6

Chemical Vapor Corrosion ......................................................... 6

Installation Clearances ............................................................... 6

Levelling...................................................................................... 6

System Connections .................................................................. 6-9

Gas Connections ........................................................................ 9-11

Gas Pressure Regulators .......................................................... 11-12

Venting The Boiler - Standard Venting....................................... 12-14

Venting Maintenance - Standard Venting .................................. 15

Venting Sidewall (Optional) Power Vent System ...................... 15

Venting System .......................................................................... 15

Safety Relief Valves .................................................................. 15-16

Wiring Connections .................................................................... 16-31

Water Line Connections ............................................................. 32

Hard Water ................................................................................. 32

T ank Temperature Control .......................................................... 32-33

Low Water Cutoff ...................................................................... 33

Thermometers ............................................................................ 33

Drain Valve (Not Supplied)......................................................... 33

Closed Water System ................................................................ 33

Piping Diagrams .......................................................................... 34-45

the locations indicated in the diagrams as these are necessary for checking the operation of the boiler.

MAKE SURE THE GAS ON WHICH THE BOILER WILL OPERA TE IS THE SAME AS THA T SPECIFIED ON THE UNIT RATING PLA TE.

The boiler installation must conform to these instructions and the requirements of the local authority having jurisdiction.

Where required by authority having jurisdiction, the installation must conform to the Standard for Controls and Safety Devices for Automatically Fired

Boilers, ANSI/ASME CSD-1.

In absence of local code requirements, the boiler installation must conform

National Fuel Gas Code, ANSI Z223.1 and/or CAN/CSA B-149.1-00

to the Installation Codes.

These manuals can be purchased from the CSA International, 8501 East Pleasant Valley Road, Cleveland, OH 44131 or 178 Rexdale Boulevard, T oronto, Ontario Canada M9W1R3.

PAGE

STA RT-UP AND OPERATING INSTRUCTIONS .................................. 45

Filling And Venting ...................................................................... 46

Pilot and Main Burner ................................................................. 46

Lighting Instructions ................................................................... 47-48

Pilot and Main Burner (Continued) ............................................. 49-51

Electronic Intermittent Pilot Ignition Control ................................. 51

Normal Operating Sequence With Honeywell S-8600H or

S-8610M Intermittent Ignition Control (I.I.D.) ............................... 52

High Altitude Installations ........................................................... 52

Thermal Balancer ....................................................................... 52

Coil High Limit Control (Protector Switch).................................. 52-53

Pressure Reducing Valve .......................................................... 53

Safety Flow Switch ................................................................... 53-54

Safety Relief Valve Maintenance ............................................... 54

Replacement Parts ..................................................................... 54

REMOVAL OF EXISTING BOILER FROM A COMMON

VENTING SYSTEM............................................................................ 54

GENERAL MAINTENANCE ................................................................ 55

Relief Valve ................................................................................ 55

CLEANING AND FLUSHING INSTRUCTIONS .................................... 55

Internal Contaminants ................................................................. 55

Hot Water Supply Boilers - Preventive Maintenance ................ 55

Deliming ....................................................................................... 55-56

Deliming Solvents ....................................................................... 56

Heavy Lime Deposits ................................................................. 56

Removing Silicate ....................................................................... 56

PRE-TROUBLE-SHOOTING ............................................................... 57

TROUBLE-SHOOTING....................................................................... 57-61

LIMITED WARRANTY........................................................................ 62

INST ALLA TION INSTRUCTIONS

REQUIRED ABILITY

INST ALLATION OR SERVICE OF THIS BOILER REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS SUPPL Y AND ELECTRICAL WORK ARE REQUIRED.

INST ALLA TION AS BOILER REPLACEMENT

Installation as boiler replacement on an old system with large water volume may experience condensation within the boiler on cold starts. This condensing of water vapor in the combustion area can be prevented if a portion of the system water flow is diverted past the boiler to cause an increase in boiler temperature rise.

With old systems where water temperature can be expected to drop appreciably due to long standby periods, a bypass pipe of at least 1" size with a balancing cock should be installed between the boiler inlet and outlet. When the system first starts, the valve should be slowly opened until the condensing ceases. This adjustment remains at a permanent setting to establish required temperature rise across the boiler.

The equipment shall be installed in accordance with those installation regulations in force in the local area where the installation is to be made. These shall be carefully followed in all cases. Authorities having jurisdiction shall be consulted before installations are made.

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 INST ALLED 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 LOCA TED 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 SUITABLE DRAIN P AN 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 flow.

WARNING FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR COMBUSTION AND VENTILATION. AN INSUFFICIENT SUPPLY OF AIR WILL CAUSE RECIRCULATION OF COMBUSTION PRODUCTS RESUL TING IN AIR CONTAMINATION THA T MA Y BE HAZARDOUS TO LIFE. SUCH A CONDITION OFTEN WILL RESUL T IN A YELLOW , LUMINOUS BURNER FLAME, CAUSING CARBONING OR SOOTING OF THE COMBUSTION CHAMBER, BURNERS AND FLUE TUBES AND CREATES A RISK OF ASPHYXIATION.

UNCONFINED SPACE

In buildings of conventional frame, brick or stone construction, unconfined 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 dilution must be obtained 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.

CONFINED SPACE

WARNING

KEEPING BOILER AREA CLEAR AND FREE FROM COMBUSTIBLE MA TERIALS, GASOLINE AND OTHER FLAMMABLE V APORS 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 MA Y BE IGNITED BY THE IGNITER OR MAIN BURNER FLAMES CAUSING FIRE OR EXPLOSION. SOME LOCAL CODES PERMIT OPERATION OF GAS APPLIANCES IF INSTALLED 18 INCHES OR MORE ABOVE THE FLOOR. THIS MA Y REDUCE THE RISK IF LOCATION IN SUCH AN AREA CANNOT BE A VOIDED.

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 MA TERIAL MUST NOT BE STORED OR USED IN THE SAME ROOM 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 with section 5.3, Air for Combustion and Ventilation, of the National Fuel Gas Code, ANSI Z223.1, or sections 7.2, 7.3, or 7.4 of CAN/CSA B149.1-00, Installation Codes, or applicable provisions of the local building codes.

Provisions for vent, bleed and gas relief lines (when applicable).

(a) U. S. INSTALLATIONS

When drawing combustion and dilution air from inside a conventionally constructed building to a confined space, such a space shall be provided with two permanent openings, ONE WITHIN 12 INCHES OF THE ENCLOSURE TOP AND ONE WITHIN 12 INCHES OF THE ENCLOSURE BOTTOM. Each opening shall have a free area of 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.

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 opening shall have a free area of not less than one square inch per 2000 Btuh of the total input of all appliances in the enclosure.

(b) CANADIAN INSTALLA TIONS

Ventilation of the space occupied by the boiler(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

)

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 1,000,000 BTUH

plus 1 square inch per 14,000 BTU in excess of

/KW) up to and including

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.

Where power vented equipment is used in the same room as the boiler, sufficient air openings must be supplied.

Keep appliance area free of combustible or flammable liquids. Do not obstruct the flow of combustion or ventilating air.

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 OF ASPHYXIA TION.

CHEMICAL V APOR CORROSION

WARNING CORROSION OF THE FLUEWAYS AND VENT SYSTEM MAY OCCUR IF AIR FOR COMBUSTION CONTAINS CERTAIN CHEMICAL V APORS WHICH BREAK DOWN INTO ACIDS A T HIGH TEMPERATURE. SUCH CORROSION MA Y RESUL T IN F AILURE AND RISK OF ASPHYXIA TION.

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.

INST ALLA TION CLEARANCES

These boilers are approved for installation on combustible flooring in an alcove with minimum clearance to combustibles of:

TABLE 4

HWB/HW HWB/HW HWB/HW HWB/HW HWB/HW

300 399 420 52 0 610 & 670

TOP 28" (71 1.2) 32" (812.8) 24" (609.6) 24" (609.6) 24" (609.6)

SIDES 6" (152.4) 6" (152.4) 24" (609.6) 24" (609.6) 24" (609.6)

REAR 6" (152.4) 6" (152.4) 24" (609.6) 24" (609.6) 24" (609.6) VENT 6" (152.4) 6" (152.4) 6" (152.4) 6" (152.4) 6" (152.4)

Two inch (50.8mm) clearance is allowable from combustible construction for hot water pipes.

Sufficient 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.

LEVELLING

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.

SYSTEM CONNECTIONS

The system installation 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 INST ALLATION

FIGURE 1

1. CONVENTIONAL INST ALLA TIONS All modern hydronic type boilers are exceptionally fast heating units.

The low water volumes in relation to firing rates require special attention to water flow rates for smooth, efficient operation. These considerations for the A. O. Smith copper heat exchanger boilers are covered below.

Conventional 10

C (200F) drop in systems for a fully loaded boiler

will maintain the following approximate flow rates:

U.S. CANADIAN

MODELS MODELS LPM GPM

HW-300 HWB-300 87 23 HW-399 HWB-399 114 30 HW-420 HWB-420 132 35 HW-520 HWB-520 148 39 HW-670 HWB-610 175 46

Figure 1 shows a typical installation of the boiler with pipe sizing and circulator selected by the installer to provide adequate water flow whenever the boiler is firing.

In a system with several large zones of which any might be smaller than approximately 1/3 of the system should include a hydronic balancer as shown in fig. 1. The balancer connects between the system supply and the return line before the circulator inlet. Adjustment of the balancing cock should permit adequate boiler flow rate when only the smallest zone is in operation.

Attention should be given to balancing inputs and water flow rates where wide variations of system flow rates can occur.

The recommended minimum flow rates that will result in approximately 30

C (500F) temperature rise across the boiler are

as follows:

ONE BOILER INSTALLED

INDEPENDENT OF THE PRIMARY SYSTEM

FIGURE 2

Total heating requirements for the building can be supplied by a series of boiler loops all connecting to a common pipe joining the system supply and return mains. The supply and return branches of each boiler loop must join the common pipe only a short nipple length apart. The different sets of branches should be installed reasonably close together, but not necessarily to the short nipple length as required for the supply and return of each set. These branches may be made with tees or with welded connections.

The installer is reminded that the total boiler flow rates need not match the system flow rate.

U.S. CANADIAN

MODELS MODELS LPM GPM

HW-300 HWB-300 34 9 HW-399 HWB-399 45 12 HW-420 HWB-420 53 14 HW-520 HWB-520 61 16 HW-610 HWB-610 69 18 HW-670

76 20

If system flow rate is unknown, or if zoning creates extreme variations in flow rates, the boiler should be installed as shown in fig. 2 for A. O. Smith

LINEAR-TEMP INSTALLA TIONS

LINEAR-TEMP installations.

A. New Installations

A. O. Smith

LINEAR-TEMP systems have been designed to provide efficient, trouble-free operation of the boiler sizes covered in this manual with any of the following conditions:

a. Unknown system flow rate b. Varying flow rate as with zoned systems c. Multiple boiler installations

Figure 2 shows piping and accessory arrangement for a boiler pumped independent of the primary system mains. Pipe sizing and boiler loop pump selection data are shown in Table 5 for several different temperature rises across the boilers.

TABLE 5

PUMP AND PIPE SIZING DA T A

(PIPING FROM TEES IN MAIN TO BOILER BRANCHES)

Quantity and Model Temp. *Pump Pipe

U. S Canadian Rise°C (°F) G.P.M. Size Size

10 (20) 23 1-1/2"PR 2"

HW-300 1 HWB-300 15 (30) 15 1 50 1-1/2"

15 (30) 15 125 1-1/4" 20 (40) 11 10 0 1" 10 (20) 30 60-13 2"

HW-399 1 HWB-399 15 (30) 20 1-1/2"HV 1-1/2"

20 (40) 15 150 1-1/2" 20 (40) 15 125 1-1/4" 10 (20) 32 60-13 2"

HW-420 1 HWB-420 15 (30) 21 1-1/2"HV 1-1/2"

20 (40) 16 150 1-1/2" 20 (40) 16 125 1-1/4" 10 (20) 39 2-1/2" 2-1/2"

HW-520 1 HWB-520 10 (20) 26 1-1/2"HV 2"

17 (35) 23 1-1/2"HV 1-1/2" 20 (40) 20 150 1-1/2" 10 (20) 51 60-13 3"

HW-670 1 HWB-610 15 (30) 34 2-1/2" 2-1/2"

17 (35) 29 2" 2" 20 (40) 25 1-1/2"HV 1-1/2"

NOTE: Pipe loop sizes and pump selections based on

50 equivalent feet of pipe and fittings.

*All pump sizes listed are B & G model numbers.

NO . SUGGESTED ITEMS FOR INST ALLA TION

1 Short pipe nipple and pair of boiler loop tees in piping

between system supply and return. One set per each

group of boilers 2 Boiler pipe loop. See piping sizing data above. 3 Boiler circulator. See pump sizing data above. 4 Thermometer. 5 Theraltimeter. 6 Plug cock to control flow rate. 7 Safety flow switches. For interlock with other systems or

instead of low water cutoff. 8 Relief valve. 9 With one -300, -399 or -420 item 9 is - sensing

element of remote control.

With a group of -300's, -399's or -420's, item 9 is - for

1st. boiler, the sensing element as above. For additional

boilers, install a 2nd. limit control if required by local codes.

With any -520, -610 or 670 boilers, install 2nd. limit control

here if required by local code.

BOILER INLET - OUTLET SIZES

10 HWB-300 - 1-1/4", HWB-399 - 1-1/2", HWB-420-1-1/2",

HWB-520 & HWB-610 - 2". Canadian Models

10 HW-300 - 1-1/4", HW-399 - 1-1/2", HW-420-1-1/2",

HW-520 & HW-670 - 2". U.S. Models

MINIMUM BRANCH SIZES TO BOILERS

1 1 HWB-300 - 1-1/4" HWB-520, 610 (Single boiler

HWB-399 - 1-1/2" per pump) 2"

HWB-420 - 1-1/2" Canadian Models

1 1 HW-300 - 1-1/4" HW-520, 670 (Single boiler

HW-399 - 1-1/2" per pump) 2"

HW-420 - 1-1/2" U.S. Models

12 Flow control valve. Required only if flow rate of system

primary is excessive for size of boiler branch tees or if

chilled water main is above boilers.

13 System supply temperature thermometer. 14 Boiler headers for three (3) boilers can be larger than pipe loop,

if desired, to aid in balancing.

SCHEMATIC OF THE LINEAR-TEMP® SYSTEM

FIGURE 3

Supply and return headers of the old system should be connected to the boiler loop with a pair of tees set close together. The boiler loop pump and the boiler(s) should be wired to operate only when any of the system pumps are in operation. The number of zone pumps that may be in operation at any particular time will take their required flow rate out from the first tee in the boiler piping. This water will be circulated through the proper branches from the supply header to the zones calling for heat. The water will be brought back to the return header and then into the second tee in the boiler pipe loop. There will be no conflict between the boiler pump and the zone pumps when the two tees in the boiler loop are placed close together.

Normal use of flow control valves is required to prevent cross circulation of zones as with any multiple pump system. Flow control is not required on boiler circuit.

The system flow rate is selected to give the desired system temperature drop - depending on the design criteria.

The boiler generator flow rates, on the other hand, should be selected to give the temperature rise through the generator that is both economical and offers the best generator efficiency.

The boiler temperature rise is normally between 10

(20

F and 400F). The system temperature that will be introduced

C and 200C

to the boiler (inlet temperature) plus the selected boiler temperature rise selected from PUMP AND PIPE SIZING DAT A should not exceed the high limit control setting of 115

C (2400F).

There should be a relation of the minimum system load to the size boiler selected as the first firing or base boiler. This will stabilize operation during minimum load periods.

B. Commercial Boiler Replacements

Application of

LINEAR-TEMP® to a commercial boiler replacement with an old multiple pump installation is an excellent way to modernize the system. The A. O. Smith boiler(s) should be installed on a pipe loop with a separate circulating pump selected from PUMP AND PIPE SIZING DA T A T ABLE.

Figure 3 shows a line drawing of how the system headers should be connected to the pipe loop installed with the replacement boiler(s). Make-up water connections and accessories are not shown.

Attention should be given to balancing gas inputs and water flow rates. Large systems with multiple boilers should include main water temperature control (with or without outdoor reset) to stage the boilers on and off in relation to the load on the system.

3. WA TER SUPPL Y LINE These boilers can be used ONLY in a forced circulation hot water

heating system. Since most forced circulation systems will be of the closed type, install the water supply line as shown on piping diagrams, fig. 1 or 2.

Fast filling of large pipe, old radiator installations and pressure purging of series loop systems (where high pressures are not available) requires bypassing of the pressure reducing valve. Generally, pressure purging is not possible with a well pump system. High point air venting is essential.

If the system is of the open type, a pressure reducing valve will not be required as the water supply to the system will be controlled by a manually operated valve. An overhead surge tank is required.

4. EXPANSION T ANK

CAUTION

A closed system will exist if a check valve (without bypass), pressure reducing valve (without bypass), or a water meter (without bypass) is installed in the cold water line between the water heater and street main (or well).

Excessive pressure may develop causing premature tank failure or intermittent relief valve operation.

This is not a warranty failure. An expansion tank or a similar device may be required in the inlet supply line between the appliance and the meter or valve to compensate for the thermal expansion of water under supply pressure, see figure 1.

If the boiler is connected to chilled water piping or its heating coils are exposed to refrigerated air, the boiler piping system must be equipped with flow valves or other automatic means to prevent gravity circulation through the boiler during the cooling cycle.

8. CIRCULATING PUMP

An air separator as shown in the piping diagrams is recommended especially for modern commercial hydronic systems.

5. VENT V ALVES

It is recommended that automatic, loose key or screwdriver type vent valves be installed at each convector or radiator.

6. MANIFOLD HEADERS Split systems with individual supply and return lines from the boiler

room should normally have this piping connected to supply and return manifold headers near the boiler. To achieve good water distribution with maximum pressure drop for several circuits, manifolds of at least 2-1/2" (64mm) diameter are suggested on HWB/HW-399, HWB/HW-420, HWB/HW-520, HWB/HW-610 and HW-670 units. HWB/HW-300 units should have 1-1/2" (38mm) diameter manifolds.

The circuits should be spaced on the header at a minimum of 3" (76mm) center to center. Install a balancing cock in each return line.

Manifold headers are recommended for split systems with or without zone valves and also those installations with zone circulators. If the system is to be split at remote points, good practice requires special attention be given to main pipe sizing to allow balancing of water flow.

The boiler piping system of a hot water boiler connected to heating coils located in air handling units where they may be exposed to refrigerated air circulation must be equipped with flow control valves or other automatic means to prevent gravity circulation of the boiler water during the cooling cycle.

CONSTANT CIRCULATING PUMP OPERATION OF THE BOILER VOIDS THE W ARRANTY. Constant water flow through the unit will “wash” away the copper’s natural protective coating. This is called velocity erosion. This erosion is not as great a problem when intermittent circulating operation is used per the recommended installation procedure. Constant circulation of water through the building’s system main is permissible as long as the water does not constantly flow through the boiler. Only all bronze or stainless steel circulators are to be used with the unit when it is installed in HOT WA TER SUPPL Y SYSTEMS .

A TYPICAL CIRCULA TING PUMP

FIGURE 5

Although each circulator that requires oiling is oiled and operated by the manufacturer, IT MUST BE OILED AGAIN BEFORE OPERATED. Oil the three oil cup s (2 on the motor, 1 on the pump) as instructed on the oil tube supplied with the unit, fig 5.

Thereafter, during the heating season, lubricate the three oil cups at least once every four months. Combination heating-cooling systems should be lubricated every four months year ‘round.

Use 2 or 3 teaspoonsful in bearing oil cups, fig. 5, and 10 or 12 drops in the motor oil cups. Use No. 20 non-detergent motor oil.

7. COOLING PIPING

When the boiler is used in conjunction with a refrigeration system it must be installed so that the chilled medium is piped in parallel with the boiler with appropriate valves to prevent the chilled medium from entering the boiler, fig. 4.

Water temperature in the heating system must be reduced to less

than 100

F (38°C) before cooling system is started, or damage to

the chiller unit may occur.

SCHEMATIC SHOWING PROPER PIPING ISOLA TION

OF THE BOILER FROM THE CHILLER

FIGURE 4

Follow the same oiling procedure if a replacement circulator is installed into the system.

GAS CONNECTIONS

WARNING

THIS BOILER IS NOT INTENDED TO OPERA TE AT GAS SUPPLY PRESSURE OTHER THAN SHOWN ON THE RATING PLATE. EXPOSURE TO HIGHER GAS SUPPL Y PRESSURE MA Y CAUSE DAMAGE TO GAS VA LVES WHICH CAN RESULT IN FIRE OR EXPLOSION. IF OVERPRESSURE HAS OCCURRED SUCH AS THROUGH IMPROPER TESTING OF GAS LINES OR EMERGENCY MALFUNCTION OF THE SUPPL Y SYSTEM, THE GAS VA LVES MUST BE CHECKED FOR SAFE OPERATION. MAKE SURE THAT THE OUTSIDE VENTS ON THE SUPPLY REGULATORS AND THE SAFETY VENT V ALVES ARE PROTECTED AGAINST BLOCKAGE. THESE ARE PARTS OF THE GAS SUPPLY SYSTEM, NOT THE BOILER. VENT BLOCKAGE MA Y OCCUR DURING ICE BUILD-UP OR SNOW STORMS.

WHEN LOCAL CODES REQUIRE A MAIN MANUAL SHUTOFF V ALVE OUTSIDE THE BOILER JACKET , A SUIT ABLE MAIN MANUAL SHUTOFF VALVE MUST BE INSTALLED IN A LOCATION COMPL YING WITH THOSE CODES.

IT IS IMPORT ANT TO GUARD AGAINST GAS V ALVE FOULING FROM CONT AMINANTS IN THE GAS WA YS. SUCH FOULING MA Y CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.

IF COPPER SUPPLY LINES ARE USED THEY MUST BE CERTIFIED FOR GAS SERVICE.

BEFORE ATTACHING THE GAS LINE BE SURE THAT ALL GAS PIPE IS CLEAN ON THE INSIDE.

TO TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS SUPPL Y LINE, A DIRT LEG (SOMETIMES CALLED DRIP LEG or sediment trap) MUST BE INCORPORA TED IN THE PIPING, SEE FIG . 1. The dirt leg must be readily accessible and not subject to freezing conditions. INSTALL IN ACCORDANCE WITH RECOMMENDA TIONS OF SERVING GAS SUPPLIERS. (Refer to National Fuel Gas Code, ANSI Z223.1 and/or CAN/CSA-B 149.1-00 Installation Codes.

To prevent damage, care must be taken not to apply too much torque when attaching gas supply pipe to gas valve gas inlet.

Fittings and unions in the gas line must be metal to metal type. Apply joint compounds (pipe dope) sparingly and only to the male

threads of pipe joints. Do not apply compound to the first two threads. Use compounds resistant to the action of liquefied petroleum gases.

THE BOILER AND ITS GAS CONNECTIONS MUST BE LEAK TESTED BEFORE PLACING THE BOILER IN OPERATION. Use soap and water solution or other material acceptable for the purpose in locating gas leaks. DO NOT USE MA TCHES, CANDLES, FLAME OR OTHER SOURCES OF IGNITION FOR THIS PURPOSE.

DISCONNECT THE BOILER AND ITS MAIN MANUAL GAS SHUTOFF VALVE FROM THE GAS SUPPLY PIPING SYSTEM DURING ANY PRESSURE TESTING OF THE GAS SUPPLY SYSTEM OVER 1/2 PSIG (3.5kPa).. THE GAS SUPPL Y LINE MUST BE CAPPED WHEN NOT CONNECTED TO THE BOILER.

2A.SIZING GAS SUPPLY LINE (For single boiler installations and

for installations of multiples of two or three of same size boilers).

Use table 6, or CAN/CSA B149.1-00 (latest recent edition) to size iron pipe or equivalent gas supply line. Table 6 is based on a pressure drop of 0.3 inches of water and a specific gravity of 0.60 approximately that of natural gas. (LP gas has an S.G. of about

1.53). If the service pressure is five inches water column or less, use one pipe size larger than specified in table 6 in order to minimize pressure drop in the line.

TABLE 6

MAXIMUM CAPACITY OF PIPE IN CUBIC FEET OF GAS PER

HOUR (BASED UPON A PRESSURE DROP OF 0.3 INCH WA TER

COLUMN AND 0.6 SPECIFIC GRA VITY GAS)

Length Meters

From Gas (Nominal Iron Pipe Size (Inches)

Meter 1/2 3/4 1 1 1/4 1 1/2 2 2 1/2 3 4

3 (10) 132 278 520 1,050 1,600 3,050 4,800 8,500 17,500 6 (20) 92 190 350 730 1,100 2,100 3,300 5,900 12,000

9 (30) 73 152 285 590 890 1,650 2,700 4,700 9,700 12 (40) 63 130 245 500 760 1,450 2,300 4,100 8,300 15 (50) 56 115 215 440 670 1,270 2,000 3,600 7,400

18 ((60) 50 105 195 400 610 1,150 1,850 3,250 6,800

21 (70) 46 96 180 370 560 1,050 1,700 3,000 6,200 24 (80) 43 90 170 350 530 990 1,600 2,800 5,800 27 (90) 40 84 160 320 490 930 1,500 2,600 5,400

30 (100) 38 79 150 305 460 870 1,400 2,500 5,100 38 (125) 34 72 130 275 410 780 1,250 2,200 4,500 45 (150) 31 64 120 250 380 710 1,130 2,000 4,100 53 (175) 28 59 110 225 350 650 1,050 1,850 3,800 60 (200) 26 55 100 210 320 610 980 1,700 3,500

*The heating value of Natural Gas is approximately 1,050 Btu/Ft.3. Propane (LP) Gas has a heating value of approximately 2,500 Btu/Ft3. 1 cu. meter=35.31 cu. feet.

Where it is necessary to use more than the average number of pipe fittings i.e. elbows, tees, and valves in gas supply line, use a pipe larger than specified to compensate for increased pressure drop.

THE BOILER MUST BE ISOLATED FROM THE GAS SUPPLY PIPING SYSTEM BY CLOSING ITS MAIN MANUAL GAS SHUTOFF VA LVE DURING ANY PRESSURE TESTING OF THE GAS SUPPL Y PIPING SYSTEM AT TEST PRESSURES EQUAL TO OR LESS THAN 1/2 PSIG (3.5kPa).

PURGING

Gas line purging is required with new piping or systems in which air has entered.

CAUTION

PURGING SHOULD BE PERFORMED BY PERSONS EXPERIENCED IN THIS TYPE GAS SERVICE TO A VOID RISK OF FIRE OR EXPLOSION. PURGE DISCHARGE MUST NOT ENTER CONFINED AREAS OR SP ACES WHERE IGNITION CAN OCCUR. THE AREA MUST BE WELL VENTILA TED AND ALL SOURCES OF IGNITION MUST BE INACTIV ATED OR REMOVED.

1. CORRECT GAS Make sure the gas on which the boiler will operate is the same as

that specified on the boiler rating plate. Do not install the boiler if equipped for a different type gas — consult your supplier.

2B. SIZING GAS SUPPLY LINE (For multiples of over three boilers

of same size or for multiple installations of two or more mixed sizes).

Capacities in cubic feet per hour of 0.60 specific gravity gas for different sizes and lengths are shown in table 6. No additional allowance is necessary for an ordinary number of fittings.

Applications of the gravity factor converts the figures given in table 6 to capacities with another gas of different specific gravity. Such application is accomplished by multiplying the capacities given in table 6 by the multipliers shown in table 7.

To determine the size of each section of gas piping in a system within the range of table 6 proceed as follows:

• Determine the gas demand of each appliance to be attached

to the piping system. When table 6 is to be used to select the piping size, calculate the gas demand in terms of cubic feet per hour for each piping system outlet. The gas demand for an appliance can be found by dividing its heat input rate by the gas’s heating value.

• Obtain or determine the length of piping from the gas meter or service regulator to the appliance(s).

1010

• In table 6, select the row showing the distance to the most remote outlet or the next longer distance if the table does not give the exact length. This is the only distance used in determining the size of any section of gas piping. If the gravity factor is to be applied, the values in the selected row of table 6 are multiplied by the appropriate multiplier from table 7.

• Total the gas demands of all appliances on the piping system. Enter table 6, on the left hand side, at the row equal to or just exceeding the distance to the most remote outlet. Select the pipe size in the row with a capacity equal to or just exceeding the total gas demand. This is the required main gas supply line size leading away from the gas meter or regulator. To determine the pipe size required for each branch outlet leading away from the main supply line, determine the gas demand for that outlet. Enter table 6 on the same row, and select the branch pipe size for a capacity equal to or just exceeding the demand at that outlet. The main line can be resized for a lesser capacity after each branch outlet, since the gas demand is reduced. Total the gas demands of all remaining appliances branching off downstream on the main gas line. Re-enter table 6 in the same row and select the appropriate pipe size with adequate capacity. Repeat the branch sizing and main line re-sizing for any remaining appliances in the system.

TABLE 7

MULTIPLIERS TO BE USED WITH T ABLE 6 WHEN APPL YING

THE GRA VITY FACTOR T O OTHER THAN .60 SPECIFIC GRAVITY

Specific Specific

Gravity Multiplier Gravity Multiplier

.35 1.31 1.00 .78 .40 1.23 1.10 .74 .45 1.16 1.20 .71 .50 1.10 1.30 .68 .55 1.04 1.40 .66

*.60 (Nat.) 1.00 *1.50 (Prop.) .63

.65 .96 1.60 .61 .70 .93 1.70 .59 .75 .90 1.80 .58 .80 .87 1.90 .56 .85 .84 *2.00 (Butane) .5 5

.90 .82 2.10 .54 *Use these correction factors if exact specific gravity of the gas is not known.

GAS PRESSURE REGULA TORS

The gas pressure regulator is included in the combination gas valve, fig. 6, and is set to operate on the gas specified on the boiler model and rating plate.

Periodically check main burner, fig. 41, and pilot flame, fig. 42, for proper operation. This should be checked every six months.

EXAMPLE Job Condition: Determining the required gas pipe size for a system composed of

two HWB/HW-420 boilers and two HWB/HW-610 boilers to be installed as a multiple group, 50 lineal feet from meter. Gas to be used has a .60 specific gravity and heating value of 1,000 Btu per cubic foot.

Solution: 2 HWB/HW-420 Boilers = 840,000 Btuh

2 HWB/HW-610 Boilers = 1,220,000 Btuh Total Btuh Input = 2,060,000 Btuh

Do not subject the gas valve to inlet gas pressures of more than 14" W.C. (1/2 P.S.I.). If higher gas pressures are encountered, a service regulator is necessary.

TABLE 8

CORRECT MANIFOLD PRESSURE FOR FULL

BOILER INPUT (IN INCHES OF WA TER COLUMN)

Model Rated Manifold Pressure

Number Input Natural Propane

HWB/HW-300 300,000 3.5 10.0 HWB/HW-399 399,000 3.2 9.5 HWB/HW-420 420,000 3.5 10.0 HWB/HW-520 520,000 3.5 10.0 HWB/HW-610 610,000 3.5 10.0

HW-670 Nat. 660,000 3.5

HW-670 Prop. 670,000 10.0

Adjustment, if required, is performed as follows:

1. Set primary system temperature control dial (thermostat) at

lowest setting so that boiler will not call for heat.

2. Attach a pressure gauge to the tapping in the control string

elbow.

3. Reset primary system temperature control dial (thermostat)

to highest setting. Main burner will now ignite.

Total Btuh Input = 2,060,000 Btuh = 2,060 cf/h Btu per Cubic Foot of Gas 1,000 With a cubic foot per hour demand of 2,060 and with 50 lineal feet

of gas supply line, table 6 shows a pipe size of 3" (76mm) is required.

NOTE: For other than .60 specific gravity, apply multiplier factor

as shown in table 7.

4. With main burner firing, adjust pressure, if necessary, by turning

pressure regulator adjusting screw with a screwdriver.

• Clockwise to increase pressure.

• Counterclockwise to decrease pressure.

5. Set primary system temperature control dial (thermostat) to

lowest setting.

6. Remove pressure gauge and replace sealing plug.

1111

7. Set primary system temperature control dial (thermostat) to desired setting.

WARNING

DO NOT INCREASE GAS PRESSURE ABOVE THAT SPECIFIED ON THE RATING PLATE, AS OVERFIRING WILL RESULT IN DAMAGE TO THE BOILER, AS WELL AS INCREASED RISK OF FIRE, SOOTING AND ASPHYXIA TION.

If gas pressure regulator cannot be adjusted to correct pressure with sufficient gas pressure at the valve, replace with new gas valve.

VENTING THE BOILER - STANDARD VENTING

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 specified in the National Fuel Gas Code, ANSI Z223.1 and/or CAN/CSA B149.1-00, Installation Codes;

Stack or chimney must be a minimum height of 12" (305mm) above the annual snow fall to prevent blockage.

Building materials must not come in contact with combustion products from stack or chimney, due to the degradating properties of flue products.

WARNING

THE INSTRUCTIONS IN THIS SECTION ON VENTING THE BOILER MUST BE FOLLOWED TO AVOID CHOKED COMBUSTION OR RECIRCULATION OF FLUE GASES. SUCH CONDITIONS CAUSE SOOTING OR RISKS OF FIRE AND ASPHYXIA TION.

TYPE B VENTING MAY BE USED WITH THESE BOILERS. ALL LOCAL UTILITY REGULATIONS ON VENTING SHOULD BE FOLLOWED.

ROBERTSHA W® 7000 DERHC

HWB/HW-300, 399,-420, -520, -610, -670 NATURAL GAS WITH I.I.D.

HW-300, -399, -420, -520, -670 LP GAS WITH I.I.D. U.S. ONLY

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.

The Canadian B149.1-00, Installation Code specifies a 6 foot horizontal vent terminal clearance to gas and electric meters and relief devices (this clearance is specified as 4 feet in the U.S. under the National Fuel Gas Code, ANSI/Z223.1). Therefore instruction provision 134.1-b19(d), which specifies compliance with the 4 foot clearance, as applies in the U.S. only, and the B149.1-00 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 confined 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 hangers 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, fig. 7. Dampers or other obstructions must not be installed in the vent. Be sure that the vent pipe does not extend beyond the inside wall of the chimney.

HWB/HW-300, 399,-420, -520, -610 SINGLE STAGE

ROBERTSHAW® 7000 ERHC (LP)

STANDING PILOT, CANADIAN ONLY

FIGURE 6

For boilers for connection to gas vents or chimneys, vent sizing, installation and termination shall be in accordance with Part 7, Venting of Equipment, of the National Fuel Gas Code, ANSI Z223.1, or Section 7, Venting Systems and Air Supply for Appliances, of the CAN/CSA B149.1-00, Installation Codes, or applicable provisions of the local building codes.

1212

VENT PIPE INST ALLA TION

FIGURE 7

® Robertshaw is a registered trademark of Fulton Controls Corp.

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 flue gas exhauster may be employed to ensure proper venting and correct combustion if permitted by local codes.

WARNING

FAILURE TO CORRECT BACK DRAFTS WILL CAUSE AIR CONTAMINA TION AND UNSAFE CONDITIONS.

Vent connectors serving appliances vented by natural draft shall not be connected into any portion of mechanical draft systems operating under positive pressure.

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, fireplace 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 latest edition of CAN/CGA B149.1-00 (latest 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 Appendix G in CAN/CSA B149.1-00.

4. MULTIPLE VENT T ABLE

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 fired 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 flue pipe from the oil fired 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 deficiencies which could cause an unsafe condition.

Table 9 has been compiled to show the material sizes in a Type B doublewall combined vent system. Refer to CAN/CSA B149 .1-00 (latest edition), or the ASHRAE 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 9, 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 floors, ceilings, partitions, walls and roofs, provided the required one inch clearance is observed. These vents should be installed in accordance with CAN/CSA B149.1-00 (latest edition).

EXAMPLE SHOWING USE OF THE HWB/HW-610 COMBINED VENT SIZING TABLE 9

1983

WARNING

Ensure sufficient supply and ventilation air . Under no circumstances should the equipment room where the boiler is installed ever be under negative pressure. Insufficient air supply can interfere with combustion and ventilation of this boiler resulting in 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 fireplace 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 five minutes of main burner operation. Use the flame of a match or candle.

1313

FIGURE 8

TABLE 9, COMBINED VENT SIZING T ABLES

Input: 300,000 Btuh Draft Hood Outlet 8"

MODEL HW/HWB-300 BOILER

Required Connector or Smoke Pipe Diameter

Connector Total Vent Height(Measured in Feet Above Draft Hood)

Rise in 10 15 20 30 40 50 60 80 100

Feet Connector Diameter (in Inches)

1 101010101010101010 2 101010101010101010 3 101010101010101010

4 or more

Number Total Total Vent Height(Measured in Feet Above Draft Hood)

if Units Input 10 15 20 30 40 50 60 80 100

Combined Btuh x 1000 Manifold and Common Vent Diameter (in Inches)*

2 600 14 12 12 12 10 10 10 10 10 3 900 16 14 14 14 12 12 12 12 12 4 1200 18 16 16 14 14 14 14 12 12

MODEL HW/HWB-399 BOILER

Input: 399,000 Btuh Draft Hood Outlet 10"

Required Connector or Smoke Pipe Diameter

Connector Total Vent Height(Measured in Feet Above Draft Hood)

Rise in 10 15 20 30 40 50 60 80 100

Feet Connector Diameter (in Inches)

1 121212121212121212 2 121212101010101010 3 121010101010101010

4 or more 10 10 10 10 10 10 10 10 10

Number Total Total Vent Height(Measured in Feet Above Draft Hood)

if Units Input 10 15 20 30 40 50 60 80 100

Combined Btuh x 1000 Manifold and Common Vent Diameter (in Inches)*

2 798 14 14 14 12 12 12 12 12 12 3 1197 18 16 16 14 14 14 14 14 12 4 1596 20 20 18 16 16 16 14 14 14

MODEL HW/HWB-420 BOILER

Input: 420,000 Btuh Draft Hood Outlet 10"

Required Connector or Smoke Pipe Diameter

Connector Total Vent Height(Measured in Feet Above Draft Hood)

Rise in 10 15 20 30 40 50 60 80 100

Feet Connector Diameter (in Inches)

1 121212121212121212 2 121212101010101010 3 121010101010101010

4 or more 10 10 10 10 10 10 10 10 10

Number Total Total Vent Height(Measured in Feet Above Draft Hood)

if Units Input 10 15 20 30 40 50 60 80 100

Combined Btuh x 1000 Manifold and Common Vent Diameter (in Inches)*

2 840 14 14 14 12 12 12 12 12 12 3 1260 18 16 16 14 14 14 14 14 12 4 1680 20 20 18 16 16 16 14 14 14

Input: 610,000 Btuh Draft Hood Outlet 12"

MODEL HW/HWB-610 BOILER

Required Connector or Smoke Pipe Diameter

Connector Total Vent Height(Measured in Feet Above Draft Hood)

Rise in 10 15 20 30 40 50 60 80 100

Feet Connector Diameter (in Inches)

1 161414141414141414 2 141414141412121212 3 141412121212121212

4 or more 12 12 12 12 12 12 12 12 12

Number Total Total Vent Height(Measured in Feet Above Draft Hood)

if Units Input 10 15 20 30 40 50 60 80 100

Combined Btuh x 1000 Manifold and Common Vent Diameter (in Inches)*

2 1220 18 18 16 16 14 14 14 14 14 3 1830 22 20 20 18 18 16 16 16 14 4 2440 26 24 22 20 20 18 18 18 16 5 3050 28 26 26 24 22 22 20 20 18 6 3660 32 28 28 26 24 24 22 22 20 7 4270 34 32 30 28 26 24 24 22 22 8 4880 36 34 32 30 28 26 26 24 24

9 5490 38 36 34 30 30 28 28 26 24 10 6100 40 38 36 32 30 30 28 26 26 1 1 6710 42 38 38 34 32 30 28 28 26 12 7320 44 42 38 36 34 32 32 30 28

MODEL HW/HWB-670 BOILER

Input: 660,000 or 670,000 Btuh Draft Hood Outlet 12"

Required Connector or Smoke Pipe Diameter

Connector Total Vent Height(Measured in Feet Above Draft Hood)

Rise in 10 15 20 30 40 50 60 80 100

Feet Connector Diameter (in Inches)

1 161414141414141414 2 141414141412121212 3 141412121212121212

4 or more 12 12 12 12 12 12 12 12 12

Number Total Total Vent Height(Measured in Feet Above Draft Hood)

if Units Input 10 15 20 30 40 50 60 80 100

Combined Btuh x 1000 Manifold and Common Vent Diameter (in Inches)*

2 1340 18 18 16 16 14 14 14 14 14

3 2010 22 20 20 18 18 16 16 16 14

4 2680 26 24 22 20 20 18 18 18 16

5 3350 28 26 26 24 22 22 20 20 18

6 4020 32 28 28 26 24 24 22 22 20

7 4690 34 32 30 28 26 24 24 22 22

8 5360 36 34 32 30 28 26 26 24 24

9 6030 38 36 34 30 30 28 28 26 24 10 6700 40 38 36 32 30 30 28 26 26 1 1 7370 42 38 38 34 32 30 28 28 26 12 8040 46 44 40 38 36 34 34 32 30

Input: 520,000 Btuh Draft Hood Outlet 10"

MODEL HW/HWB-520 BOILER

Required Connector or Smoke Pipe Diameter

Connector Total Vent Height(Measured in Feet Above Draft Hood)

Rise in 10 15 20 30 40 50 60 80 100

Feet Connector Diameter (in Inches)

1 141414121212121212 2 121212121212121212 3 121212121010101010

4 or more 12 12 12 12 10 10 10 10 10

Number Total Total Vent Height(Measured in Feet Above Draft Hood)

if Units Input 10 15 20 30 40 50 60 80 100

Combined Btuh x 1000 Manifold and Common Vent Diameter (in Inches)*

2 1040 16 16 14 14 14 14 12 12 12 3 1560 20 18 18 16 16 14 14 14 14 4 2080 22 22 20 18 18 18 16 16 14 5 2600 26 24 22 20 20 18 18 18 18 6 3120 28 26 24 22 22 20 20 18 18 7 3640 30 28 26 24 24 22 22 20 20 8 4160 32 30 28 26 24 24 22 22 20

Known: (5) model HWB/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 HWB/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 this table (total vent height) at 30 and the side at 5 boilers. A manifold diameter of 24" (610mm) is indicated.

1414

VENTING MAINTENANCE - ST ANDARD 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 flue which will retard free draft. Replace any damaged or deteriorated parts of the venting system.

Qualified 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 STA TIC CREATING MATERIAL TO CLEAN DUST AND CARBON DEPOSITS FROM HEA TING SURFACES AND VENT.

SUCH DEPOSITS ARE FLAMMABLE AND MAY BE IGNITED BY STATIC ELECTRICITY . USE A METAL BRUSH TO MINIMIZE THE DANGER OF EXPLOSION.

1. Turn off the electrical power (main manual gas shutoff and pilot valves, if applicable).

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 flame will be drawn into the draft hood. If not, the combustion products will tend to extinguish this flame. IF THE COMBUSTION PRODUCTS ARE ESCAPING FROM THE RELIEF OPENING OF THE DRAFT HOOD, DO NOT OPERA TE THE EQUIPMENT UNTIL PROPER ADJUSTMENT OR REPAIRS ARE MADE TO PROVIDE ADEQUA TE 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. Repeat step C above, checking the draft on each appliance.

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 HWB/HW Power Vent Kit Inst allation Instructions for proper wiring and installation procedures. Contact your local A.O. Smith representative for details.

VENTING SYSTEM

HA VE VENTING SYSTEM CHECKED EVERY SIX MONTHS FOR OBSTRUCTIONS AND/OR DETERIORA TION IN VENT PIPING.

FIGURE 9

SAFETY RELIEF V AL VES

Your local code authority may have other specific relief valve requirements not covered below.

W ARNING

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 CONT AIN ANY V ALVES BETWEEN THE BOILER AND THE RELIEF VAL VE OR THE RELIEF V AL VE 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 THA T IT NA TURALL Y DRAINS ITSELF.

If any safety relief valve is replaced, the replacement valve must comply with the latest version of the ASME Boiler and Pressure Vessel 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. 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 fireplace dampers.

B. After allowing appliance to operate for five 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

A. O. Smith supplies Canadian HW boilers for hot water supply systems with a 125 psi pressure relief valve. This valve must be installed in the water outlet as near to the boiler as possible.

A. O. Smith United States HW and Canadian HWB boilers for space heating are shipped with a 50 psi pressure relief valve. This valve must be installed in the water outlet as near to the boiler as possible.

An ASME rated temperature and pressure relief valve must be installed on each and every water storage tank in a hot water supply system.

1515

The storage tank temperature and pressure (T & P) relief valve must comply with the applicable construction provisions of the Standard for Relief Valves and Automatic Gas Shutoff Devices for Hot Water Supply Systems, Z21.22 and/or CAN1-4.4. The T & P valve must be of the automatic reset type and not embody a single-use type fusible plug, cartridge or linkage.

The T & P relief valve should have a maximum temperature rating

of 100

C (2100F), 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 the upper 6 inches from the top of the tank. See figures 20 to 31. Tapping shall be threaded in accordance with the latest version of the Standard for Pipe Threads, General Purpose (inch), ANSI/ASME B1.20.1

The boiler, when installed, must be electrically bonded to ground in accordance with the requirements of the authority having jurisdiction or, in the absence of such requirements, with the National Electrical Code, ANSI/NFPA 70 and/or the Canadian Electrical Code Part 1, CSA C22.1, Electrical Code.

STRICT ADHERENCE TO PIPING AND WIRING DIAGRAMS IS REQUIRED TO PREVENT CONSTANT PUMP OPERATION WHEN SYSTEM TEMPERA TURE CONTROL IS SA TISFIED. OTHERWISE THE WARRANTY IS VOID AS STIPULATED IN THE LIMITED WARRANTY ON THE INSTRUCTIONS MANUAL.

The electrical connections must be made so that the circulator will operate before the gas valve opens. At no time may the controlling system allow the burner to fire when there is no water flow through the boilers.

Refer to the diagrams in fig’s. 10 thru 11C for proper wiring sequence with conventional single boiler installations.

Mark location with a Class lll label. See ANSI Z21.10.1, Part 1, MARKING, See CAN/CSA B149.1-00.

WIRING CONNECTIONS

CAUTION

LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN SERVICING CONTROLS. WIRING ERRORS CAN CAUSE IMPROPER AND DANGEROUS OPERA TION. VERIFY PROPER OPERA TION AFTER SERVICING.

1. CONVENTIONAL INST ALLATIONS ALL ELECTRICAL WORK MUST BE INST ALLED IN ACCORDANCE

WITH NATIONAL ELECTRICAL CODE, ANSI/NFP A 70 AND/OR THE CANADIAN ELECTRICAL CODE, P ART 1, CSA C22.1, ELECTRICAL CODE AND MUST CONFORM TO LOCAL REGULATIONS.

The THERMAL BALANCER shown is factory included by A. O. Smith as part no. 98190. This device serves as a pump shutdown delay switch to balance the rising boiler water temperature to system temperature before the pump stops. Overshooting of boiler temperature is prevented and stack loss after shutdown is negligible.

WARNING

AN ELECTRICAL GROUND IS REQUIRED TO REDUCE RISK OF ELECTRIC SHOCK OR POSSIBLE ELECTROCUTION. Make the ground connection to the screw provided in the electrical supply junction box on the boiler.

IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED WITH THE APPLIANCE, MUST BE REPLACED, IT MUST BE REPLACED WITH TYPE 105 SENSOR AND IGNITION CABLE WHICH ARE 2500C AND WIRES CONNECTED TO THE COIL PROTECTOR WHICH ARE 2000C.

C WIRE OR ITS EQUIVALENT , EXCEPT FOR THE FLAME

1616

CONNECTION DIAGRAM

HWB & HW-300, -399, -420, -500 & -610

(NATURAL GAS)

SINGLE ST AGE I.I.D. - ROBERTSHAW® GAS V ALVE

HWB & HW-300, -399, -420, -520, -610 (NATURAL GAS ONL Y) - CANADIAN MODELS

® Robertshaw is a registered trademark of Fulton Controls Corp.

FIGURE 10

1717

CONNECTION DIAGRAM

HWB, HW-420,-520, -610

(PROP ANE GAS)

SINGLE STAGE PROP ANE - ROBERTSHAW GAS V AL VE

24 VOL T -HW, HWB-420, -520, -610 CANADIAN MODELS

FIGURE 11

1818

CONNECTION DIAGRAM HWB & HW 300, 399

(PROP ANE GAS)

FIGURE 13

SINGLE STAGE PROP ANE ROBERTSHA W GAS V ALVE

24 VOLT - HWB, HW -300, 399 CANADIAN MODELS

FIGURE 11A

1919

HW-300, HW-399, HW-420, HW-500 & HW-670

(NA TURAL GAS)

SINGLE ST AGE I.I.D. - ROBERTSHAW GAS V ALVE

HW-300, -399, -420, -520 & 670 (NA TURAL GAS ONL Y) - U.S. MODELS

FIGURE 11B

2020

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