Crown Boiler AWR175 Installation guide

Manufacturer of Hydronic Heating Products

P.O. Box 14818 3633 I. Street

Philadelphia, PA 19134

www.crownboiler.com

WARNING: Improper installation,

adjustment, alteration, service or

maintenance can cause property

damage, injury, or loss of life.

For assistance or additional

information, consult a qualied

installer, service agency or

the gas supplier. Read these

instructions carefully before

installing.

Models:

• AWR038

• AWR070

• AWR105

• AWR140

• AWR175

• AWR210

• AWR245

• AWR280

AWR Series

Gas-Fired Natural Draft Hot Water Boilers

INSTALLATION INSTRUCTIONS

These instructions must be axed on or adjacent to the boiler

D ESIGNED TO L EAD

Equipped with Honeywell

S9361A Control System

9902339

1

FOLLOW ALL INSTRUCTIONS and warnings

printed in this manual and posted on the boiler.

INSPECT THE BOILER ANNUALLY. To keep your

boiler safe and efficient, have a service technician

follow the Service checklist near the end of this

manual.

IF YOU ARE NOT QUALIFIED to install or service

boilers, do not install or service this one.

THE BOILER MAY LEAK WATER at the end of

its useful life. Be sure to protect walls, carpets,

and valuables from water that could leak from the

boiler.

PROTECT YOUR HOME IN FREEZING

WEATHER. A power outage, safety lockout, or

component failure will prevent your boiler from

lighting. In winter, your pipes may freeze and

cause extensive property damage. Do not leave

the heating system unattended during cold weather

unless alarms or other safeguards are in place to

prevent such damage

DO NOT BLOCK AIR FLOW into or around the

boiler. Insufficient air may cause the boiler to

produce carbon monoxide or start a fire.

KEEP FLAMMABLE LIQUIDS AWAY from the

boiler, including paint, solvents, and gasoline.

The boiler may ignite the vapors from the liquids

causing explosion or fire.

KEEP CHILDREN AND PETS away from hot

surfaces of the boiler, boiler piping, and vent pipe.

CARBON MONOXIDE (CO) is an odorless, deadly

gas that may be introduced into your home by

any malfunctioning fuel-burning product or vent

system failure. Consider installing CO alarms near

bedrooms in all levels of the building to warn you

and your family of potential CO exposure.

READ THIS ENTIRE MANUAL before attempting

installation, start-up, or service. Improper

installation, adjustment, alteration, service, or

maintenance may cause serious property damage,

personal injury, or death.

DO NOT DISCONNECT PIPE FITTINGS on the

boiler or in the heating system without first verifying

that the system is cool and free of pressure and

that your clothing will protect you from a release

of hot water or steam. Do not rely solely on the

boiler’s temperature and pressure gage when

making this judgment.

USE PROPER PERSONAL PROTECTION

EQUIPMENT when servicing or working near the

boiler. Materials of construction, flue products, and

fuel contain alumina, silica, heavy metals, carbon

monoxide, nitrogen oxides, and/or other toxic or

harmful substances that can are hazardous to

health and life and that are known to the State of

California to cause cancer, birth defects, and other

reproductive harm.

INSTALL ALL GUARDS, cover plates, and

enclosures before operating the boiler.

SIZE THE BOILER PROPERLY relative to the

design heat load or, if using domestic hot water

priority, the peak hot water load, whichever

is larger. A grossly oversized boiler will cycle

excessively and this will lead to premature failure

of the boiler and its components. Our warranty

does not apply to damage from excessive cycling.

ADHERE TO ALL LOCAL CODE

REQUIREMENTS. Contact your local code

inspector prior to installation. In the absence of

a local code, adhere to the National Fuel Gas

Code ANSI Z223.1/NFPA 54 or CAN/CSA B149.1,

Natural Gas and Propane Installation Code.

ALL WIRING must comply with the National

Electrical Code ANSI/NFPA 70 (in the USA) or the

Canadian Electrical Code CSA C22.1 (in Canada)

and any local regulations.

WARNINGS FOR THE HOMEOWNER

WARNINGS FOR THE INSTALLER

2

Table of Contents

I. Product Description ............................................................................... 3

II. Specications ......................................................................................... 3

III. Before Installing .................................................................................... 4

IV. Locating the Boiler ................................................................................ 4

V. Air for Combustion & Ventilation ......................................................... 6

VI. Venting ................................................................................................... 10

VII. Gas Piping .............................................................................................. 13

VIII. System Piping ........................................................................................ 14

IX. Wiring .................................................................................................... 19

X. Start-Up & Checkout ............................................................................. 24

XI. Operation ............................................................................................... 28

XII. Service & Maintenance .......................................................................... 36

XIII. Troubleshooting ..................................................................................... 38

XIV. Parts ....................................................................................................... 42

3

I Product Description

The AWR series boiler is a cast iron gas red water boiler designed for use in closed forced circulation heating systems.

This boiler is a Category I drafthood equipped appliance, which must be vented by natural draft using a lined masonry

or listed metal chimney system. An adequate supply of air for combustion, ventilation and dilution of ue gases must be

available in the boiler room.

II Specications

FIGURE 2.1: GENERAL CONFIGURATION

Notes:

1) The Net AHRI Water Ratings shown are based on a piping and pickup allowance of 1.15.

2) The manufacturer should be consulted before selecting a boiler for installations having unusual piping and pickup requirements, such as intermittent system

operation, extensive piping systems, etc.

3) Add Sux N for Natural Gas or Sux L for Propane Gas to basic Boiler Model shown (Example: AWR210EN, AWR210EL)

AWR SPACE HEATING RATINGS

NUMBER

OF

SECTIONS

DIMENSIONS (INCHES)

BASIC

BOILER

MODEL

3

INPUT

HEATING

CAPACITY

1

NET AHRI

RATING,

WATER

AFUE

‘A’ ‘B’ ‘C’

MBH MBH MBH %

AWR038E

38 32 28 83.0 2 9-3/4 31-1/2 4

AWR070E

70 58 50 83.5 3 12-7/8 31-1/2 4

AWR105E

105 87 76 83.7 4 15-3/8 31-1/2 5

AWR140E

140 117 102 83.6 5 18-1/2 31-1/2 6

AWR175E

175 146 127 83.5 6 21-1/2 31-3/4 7

AWR210E

210 175 152 83.4 7 24-5/8 33-1/2 7

AWR245E

245 205 178 83.4 8 27-5/8 33-1/2 8

AWR280E

280 234 203 83.3 9 30-3/4 33-1/2 8

TABLE 2.2 SPECIFICATIONS

4

III Before Installing

1) Safe, reliable operation of this boiler depends upon installation by a professional heating contractor in strict accordance with

this manual and the requirements of the authority having jurisdiction.

• In the absence of an authority having jurisdiction, installation must be in accordance with this manual and the

National Fuel Gas Code, ANSI Z223.1-latest edition.

• Where required by the authority having jurisdiction, this installation must conform to the Standard for Controls and

Safety Devices for Automatically Fired Boilers (ANSI/ASME CSD-1)-latest edition.

2) Make sure that a properly sized chimney is available which is in good condition. Consult the authority having jurisdiction,

Part VI of this manual, and the National Fuel Gas Code for additional information on venting requirements.

3) Make sure that the boiler is correctly sized:

• For heating systems employing convection radiation (baseboard or radiators) use an industry accepted sizing method

such as the I=B=R Guide RHH published by the Air-Conditioning, Heating and Refrigeration Institute (AHRI).

• For new radiant heating systems refer to the radiant tubing manufacturer’s boiler sizing guidelines.

• For systems including a Crown Mega-Stor indirect water heater, size the boiler to have either the Heating Capacity

required for the Mega-Stor or the I=B=R Net Rating required for the heating system, whichever results in the larger

boiler.

• For systems that incorporate other indirect water heaters, refer to the indirect water heater manufacturer’s instruc-

tions for boiler output requirements.

4) Make sure that the boiler received is congured for the correct gas (natural or LP).

5) Boilers built for installations at altitudes above 2000 ft. require dierent main burner orice. Make sure that the boiler is

congured for use at the correct altitude.

IV Locating the Boiler

1) Clearances:

• Observe minimum clearances shown below to avoid potential re hazard. These clearances apply to all combustible

construction as well as noncombustible walls, ceilings and doors. Also see Figures 4.1 and 4.2.

Front (AWR038-210) - 6”

Front (AWR245-280) - Alcove

Left Side - 1” (requires relocation of relief valve to right hand side of boiler - Figure 8.2)

Right Side - 4”

Rear - 6”

Top - 24-1/2” Additional Height May Be Required To Maintain 6” Clearance From All Breeching Components

• A 24” service clearance from the jacket is recommended on the left, right, and front of the boiler. These clearances may

be reduced to those shown in Figures 4.1 & 4.2 , however servicing the boiler will become increasingly dicult as these

service clearances are reduced.

WARNING

FAILURE TO OBSERVE THE FOLLOWING LOCATION REQUIREMENTS COULD RESULT

IN A FIRE, EXPLOSION OR CARBON MONOXIDE (CO) HAZARD.

5

F I G U R E 4 . 1 : A W R 0 3 8 - 2 1 0 M I N I M U M C L E A R A N C E F R O M B O I L E R T O A L L T Y P E S O F C O M B U S T I B L E

CONSTRUCTION AND NONCOMBUSTIBLE CEILINGS, WALLS AND DOORS (CLOSET)

F I G U R E 4 . 2 : A W R 2 4 5 - 2 8 0 M I N I M U M C L E A R A N C E F R O M B O I L E R T O A L L T Y P E S O F C O M B U S T I B L E

CONSTRUCTION AND NONCOMBUSTIBLE CEILINGS AND WALLS (ALCOVE)

6

2) The boiler must be installed on a hard level surface. This surface may be combustible.

3) Do not install this boiler in a location where gasoline or other ammable vapors or liquids will be stored or used.

4) Do not install this boiler in an area where large amounts of airborne dust will be present, such as a workshop.

5) The boiler should be located as close to the chimney as possible.

6) Do not install this boiler over carpeting. This may cause a re.

7) Do not install this boiler directly on a surface that may get wet. Raise the boiler on a pad.

8) Protect ignition system components from sources of water that may spray, drip or rain on them during installation or service.

9) Level boiler using shims as necessary.

V Air for Combustion and Ventilation

Sucient fresh air must be supplied for combustion, ventilation, and ue gas dilution. Provisions for an adequate fresh air

supply must be made in accordance with local codes, or in the absence of such codes, the National Fuel Gas Code (NFPA 54/

ANSI Z223.1). In Canada, refer to the Natural Gas and Propane Installation Code (CAN/CSA 149.1).

The National Fuel Gas Code describes three basic ways to supply this boiler with adequate fresh air:

Indoor Combustion Air – Combustion air is drawn into the boiler room from other parts of the building and from the outdoors

through natural inltration (cracks under doors, etc). This method can not be used in all cases – see discussion below.

Outdoor Combustion Air – Combustion air is brought directly into the boiler room from outdoors through ducts or grills sized

and installed specically for this purpose.

Mechanical Combustion Air Supply – Combustion air is brought into the room from outdoors using a blower system that is

engineered specically for this purpose.

Each of the above methods is described in more detail in the following sections. The National Fuel Gas Code also describes

some acceptable variations on these techniques that do not appear here.

Using the Indoor Combustion Air Method

1) Total the input of all appliances in the boiler room in thousands of BTU/hr.

2) Find the volume of the boiler room in cubic feet:

Volume (ft

3

) = Length (ft) x Width (ft) x Height (ft)

If the boiler room adjoins another room and there is no door present between these two rooms, add the volumes of the

WARNING

• INSUFFICIENT COMBUSTION AIR SUPPLY MAY RESULT IN THE PRODUCTION AND

RELEASE OF DEADLY CARBON MONOXIDE (CO) INTO THE HOME WHICH CAN CAUSE

SEVERE PERSONAL INJURY OR DEATH.

• THIS BOILER IS NOT DESIGNED FOR USE IN A SPACE THAT IS DEPRESSURIZED

RELATIVE TO THE OUTDOORS. OPERATING THIS BOILER IN A DEPRESSURIZED SPACE

MAY CAUSE SEVERE PERSONAL INJURY OR DEATH.

7

rooms together. Repeat for any other connected rooms which do not have doors. Do not add the volume of two rooms

separated by a door even if that door is “always left open”.

3) Divide the volume obtained in Step 2 by the input calculated in Step 1.

4) If the result is at least 50 ft

3

per 1000BTU/hr, and neither of the conditions described in (6) below are met, normal inl-

tration should provide adequate fresh air into the boiler room.

5) If the result is less than 50 ft

3

per 1000BTU/hr, provide two openings into the boiler room, one near the oor and one

near the ceiling. The top edge of the upper opening must be within 12” of the ceiling and the bottom edge of the lower

opening must be within 12” of the oor (Figure 5.1):

• Each opening must have a free area of 1 square inch per 1000 BTU/hr input of all gas burning appliances in the

boiler room. The minimum opening dimension is 3 inches. Minimum opening free area is 100 square inches per

opening.

• If the total volume of both the boiler room and the room to which the openings connect is less than 50 cubic feet

per 1000 BTU/hr of total appliance input, install a pair of identical openings into a third room. Connect additional

rooms with openings until the total volume of all rooms is at least 50 cubic feet per 1000 BTU/hr of input.

• The “free area” of an opening takes into account the blocking eect of mesh, grills, and louvers. Where screens are

used, they must be no ner than ¼” (4 x 4) mesh.

• If providing openings into adjacent rooms is undesirable, use the Outdoor Combustion Air Method.

6) Do not use the Indoor Combustion Air Method described above if either of the following are true:

a. The indoor space is so tightly constructed that the number of air changes per hour is known to be 0.4 or less.

b. The boiler room is depressurized relative to the outdoors. This depressurization is possible if the structure is

tightly constructed and/or is equipped with exhaust fans.

Example:

An AWR105EN and a water heater are to be installed in a room measuring 6 ft - 3 in x 7 ft with an 8 ft ceiling. The

water heater has an input of 30000 BTU/hr:

Total input in thousands of BTU/hr = (105000 BTU/hr + 30000 BTU/hr) ÷ 1000 = 135

Volume of room = 6.25 ft x 7 ft x 8 ft = 350 ft

3

FIGURE 5.1: INDOOR COMBUSTION AIR METHOD

8

350÷135 = 2.59. Since 2.59 is less than 50, there will be an inadequate fresh air supply in the boiler room un-

less openings are installed between the boiler room and at least one adjacent room. It turns out that the boiler room

in this example is adjacent to a full basement which is 20ft x 45ft x 8ft high. If two openings are installed into this

basement that each have a free area of 135in

2

, the combined volume of the boiler room and basement will be:

350ft

3

+ 6400ft

3

= 6750ft

3

and:

6750÷135 = 50ft

3

per 1000 BTU/hr.

In the absence of one of the conditions described in (6) above, this arrangement should provide an adequate fresh

air supply to all the appliances in the boiler room.

FIGURE 5.2: ALL AIR FROM OUTDOORS, VENTILATED CRAWL SPACE AND ATTIC

FIGURE 5.3: ALL AIR FROM OUTDOORS, VIA VENTILATED ATTIC

9

Using the Outdoor Combustion Air Method

1) Openings must be installed between the boiler room and the outdoors or a ventilated space, such as an attic or crawl

space, which communicates directly with the outdoors.

2) Two openings are required. The top edge of the upper opening must be within 12 inches of the ceiling. The bottom edge

of the lower opening must be within 12 inches of the oor.

3) Size openings and ducts as follows:

• Vertical ducts or openings directly outdoors (Figure 5.2, Figure 5.3, and Figure 5.4) - Each opening must have a free

cross sectional area of 1 square inch per 4000 BTU/hr of the total input of all gas-red appliances in the boiler room.

Minimum opening size is 3 inches.

• Openings to outdoors via horizontal ducts (Figure 5.5) - Each opening must have a free cross sectional area of 1

square inch per 2000 BTU/hr of the total input of all gas red appliances in the boiler room. Minimum opening size

is 3 inches.

• The “free area” of an opening takes into account the blocking eect of mesh, grills, and louvers. Where screens are

used, they must be no ner than ¼” (4 x 4) mesh.

FIGURE 5.4: OUTDOOR COMBUSTION AIR METHOD: USING OPENINGS INTO BOILER ROOM

FIGURE 5.5: OUTDOOR COMBUSTION AIR METHOD: USING HORIZONTAL DUCTS INTO BOILER ROOM

10

• If motorized louvers are installed in the openings to the outdoors, they must be interlocked to prevent operation of

the fuel burning appliances in the boiler room unless the louvers are open.

Mechanical Combustion Air Supply

A mechanical system may be used to bring all combustion air to the boiler which meets all of the following requirements:

1) The system must be manufactured specically for this purpose.

2) Size the system to deliver combustion air at the rate prescribed by the system manufacturer’s instructions, but no less

than 0.35 CFM for each 1000 BTU/hr of the combined input of all fuel burning appliances in the boiler room. If

exhaust fans are present within the building, additional capacity may be required to prevent the boiler room from being

depressurized.

3) The system must be interlocked to prevent operation of the fuel burning appliances in the boiler room if the system is not

operating.

VI Venting

The vent system installation must be in accordance with local codes, or in the absence of such codes, the National Fuel Gas

Code (NFPA 54/ANSI Z223.1). In Canada, refer to the Natural Gas and Propane Installation Code (CAN/CSA 149.1).

A typical vent installation is illustrated by Figure 6.1. The components of vent installation are boiler draft diverter, vent

damper, vent connector and chimney. The AWR series boilers are equipped with a draft hood which is built into the boiler; do

not attempt to install an external draft hood.

1) Acceptable Chimneys - The following chimneys may be used to vent AWR series boilers:

• Listed Type B or L gas vent - Install in accordance with the manufacturer’s instructions, the terms of its listing, and

applicable codes.

• Masonry Chimney - The masonry chimney must be constructed in accordance with local codes, or in the absence of

any, the Standard for Chimneys, Fireplaces, Vents, and Solid Fuel Burning Appliances (NFPA 211). The chimney

must be lined with a clay liner or other listed lining system. Do not vent an AWR series boiler into an unlined

chimney.

2) Acceptable Vent Connectors - The following may be used for vent connectors:

• Listed type B or L Gas Vent

• Single Wall Galvanized Pipe - Use 0.018” (26 gauge or heavier). The size and location of the chimney may not

permit the use of a single wall connector in some cases. (see the National Fuel Gas Code). Do not use single wall

pipe for vent connectors in attics.

• Other Vent Connectors Permitted by the National Fuel Gas Code.

3) Chimney and Vent Connector Sizing - Size the chimney and vent connector in accordance with the National Fuel Gas

Code.

WARNING

• IMPROPER VENTING MAY RESULT IN PROPERTY DAMAGE AND/OR THE RELEASE OF

FLUE GASES, WHICH CONTAIN DEADLY CARBON MONOXIDE (CO), INTO THE HOME,

WHICH CAN CAUSE SEVERE PERSONAL INJURY OR DEATH.

• DO NOT USE PLASTIC VENTING MATERIALS (SUCH AS CPVC, PVC AND RADEL) TO VENT

THIS BOILER.

• INSPECT EXISTING CHIMNEY BEFORE INSTALLING BOILER. FAILURE TO CLEAN OR

REPLACE DAMAGED PIPE OR TILE LINING WILL CAUSE SEVERE INJURY OR DEATH.

11

4) Exterior Chimneys - An exterior chimney has one or more sides exposed to the outdoors below the roof line. The

National Fuel Gas Code prescribes two conditions under which an exterior chimney may be used:

• In some very restrictive cases, the AWR series boilers may be vented into an exterior ceramic lined masonry

chimney. See the National Fuel Gas Code for information on when exterior chimneys may be used.

• An exterior masonry chimney may be used if it is lined with B vent or a listed chimney lining system.

5) This boiler may be vented using a listed power venter. The power venter must be in sized and installed in accordance

with the power venter manufacturer’s instructions, the terms of the power venter listing, and applicable codes. The boiler

must be electrically interlocked with the power venter to prevent boiler operation if the power venter fails to operate.

Before deciding to use a power venter, make certain that the ue gas exiting the power venter will not damage adjacent

construction or other structures. Also make certain that the power venter terminal will not be subjected to winds which

could aect power venter operation.

6) Do not connect the vent of this appliance into any portion of a mechanical vent system operating under positive pressure.

7) Do not connect the boiler into a chimney ue serving an open replace or other solid fuel appliance.

8) Prior to boiler installation, inspect chimney for obstructions or other defects and correct as required. Clean chimney as

necessary.

9) Vent pipe should slope upward from draft diverter not less than one inch in four feet. No portion of vent pipe should run

downward or have sags. Vent pipe must be securely supported.

10) The vertical section of vent pipe coming o the boiler should be as tall as possible, while still maintaining the proper

clearance from the horizontal vent connector to combustibles and the proper pitch called for in (9) above.

11) Vent pipe should be installed above the bottom of the chimney to prevent blockage.

12) Vent pipe must be inserted ush with inside face of the chimney liner and the space between vent pipe and chimney

sealed tight.

13) Do not install the vent damper in any portion of the vent system which is used by appliances other than the boiler being

installed.

FIGURE 6.1: TYPICAL VENT SYSTEM INSTALLATION AND COMPONENTS

12

14) Vent damper installation is mandatory on all AWR series boilers. Install vent damper (see Figure 6.2) as follows:

a) Open vent damper carton and remove installation instructions. Read the instructions thoroughly before proceeding.

Verify that vent damper is same size as draft diverter outlet (Figure 2.1). Unpack vent damper carefully. Do not

force closed damper blade. Forcing vent damper closed may result in damaged gear train and void warranty.

b) Vent damper is factory shipped having approximately ¾” diameter hole in the vent damper blade, which must be

plugged on all AWR boilers. Use the plug supplied with the damper.

c) Mount the vent damper on the ue collar without modication to either and secure with sheet metal screws. Make

sure screws do not interfere with damper blade operation. Vent damper blade position indicator must be visible to

users.

d) The damper wire harness is shipped pre-wired into the boiler. Plug the loose end of this harness into the damper and

secure the exible conduit to the damper using a connector nut provided.

Provide adequate clearance to combustible construction and servicing.

e) Install vent connector pipe and vent ttings from vent damper outlet to chimney or gas vent. Secure with sheet metal

screws and support as required.

Removing an Existing Boiler from a Common Chimney

In some cases, when an existing boiler is removed from a common chimney, the common venting system may be too large

for the remaining appliances. At the time of removal of an existing boiler the following steps shall be followed with each

appliance remaining connected to the common venting system placed in operation, while the other appliances remaining

connected to the common venting system are not in operation.

a) Seal any unused opening in the common venting system.

b) Visually inspect the venting system for proper size and horizontal pitch and determine there is no blockage or

restriction, leakage, corrosion and other deciencies which could cause an unsafe condition.

c) Insofar as practical, close all building doors and windows and all doors between the space in which all 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. Do not operate a summer exhaust fan. Close

replace dampers.

d) Place in operation the appliance being inspected. Follow the lighting instructions. Adjust thermostat so the appliance

will operate continuously.

e) Test for spillage at the draft hood relief opening after ve (5) minutes of main burner operation. Use the ame of a

match or candle, or smoke from a cigarette, cigar, or pipe.

FIGURE 6.2: VENT DAMPER INSTALLATION DETAILS

13

WARNING

• SHUT OFF GAS SUPPLY BEFORE SERVICING THE BOILER.

• ALL GAS PIPING MUST BE GAS TIGHT. USE GAS RATED THREAD COMPOUND

ON ALL THREADED JOINTS TO AVOID LEAKS, WHICH MAY RESULT IN FIRE OR

EXPLOSION.

• SIZE GAS PIPING, REGULATORS, VALVES AND METERS SO AS TO PROVIDE AN

ADEQUATE GAS FLOW AND PRESSURE TO THE BOILER DURING OPERATION.

FAILURE TO DO SO MAY CAUSE POOR COMBUSTION, NOISE, INJURY OR

DEATH.

FIGURE 7.1: GAS CONNECTION TO BOILER

f) 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

appliances to their previous condition of use.

g) Any improper operation of the common venting system should be corrected so the installation conforms with the

National Fuel Gas Code, ANSI Z223.1. 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 Part 10

of the National Fuel Gas Code, ANSI Z223.1.

VII Gas Piping

Gas piping to the boiler must be sized to deliver adequate gas for the boiler to re at the nameplate input at a line pressure

between the minimum and maximum values shown on the rating plate. For more information on gas line sizing, consult the

utility or the National Fuel Gas Code.

Figure 7.1 shows typical gas piping connection to the AWR boiler. A sediment trap must be installed upstream of all gas

controls. Install a manual shut-o valve outside the jacket and ground joint union as shown.

The boiler and its gas connection must be leak tested before placing the boiler in operation. When doing this, the boiler and

its individual shut-o must be disconnected from the rest of the system during any pressure testing of that system at pressures

in excess of 1/2 psi. When pressure testing the gas system at pressures of 1/2 psi or less, isolate the boiler from the gas supply

system by closing its individual manual shut-o valve.

14

WARNING

• INSTALL BOILER SO THAT THE GAS IGNITION SYSTEM COMPONENTS ARE

PROTECTED FROM WATER (DRIPPING, SPRAYING, RAIN, ETC.) DURING

APPLIANCE OPERATION AND SERVICE (CIRCULATOR REPLACEMENT, ETC.).

• OPERATION OF THIS BOILER WITH CONTINUOUS RETURN TEMPERATURES

BELOW 120°F CAN CAUSE SEVERE HEAT EXCHANGER CORROSION DAMAGE.

• OPERATION OF THIS BOILER IN A SYSTEM HAVING SIGNIFICANT AMOUNTS OF

DISSOLVED OXYGEN CAN CAUSE SEVERE HEAT EXCHANGER CORROSION

DAMAGE.

• DO NOT USE TOXIC ADDITIVES, SUCH AS AUTOMOTIVE ANTIFREEZE, IN A

HYDRONIC SYSTEM.

• PIPE RELIEF VALVE DISCHARGE TO A SAFE LOCATION. THE RELIEF VALVE

MAY DISCHARGE SCALDING HOT WATER.

• DO NOT INSTALL A VALVE IN THE RELIEF VALVE DISCHARGE LINE.

• DO NOT MOVE RELIEF VALVE FROM FACTORY LOCATION.

• DO NOT PLUG RELIEF VALVE DISCHARGE. BLOCKING THE RELIEF VALVE MAY

RESULT IN BOILER EXPLOSION.

VIII System Piping

Standard Piping

Figure 8.3 shows typical boiler system connections on a single zone system. Additional information on hydronic system

design may be found in the I=B=R Guide RHH published by the Air-Conditioning, Heating and Refrigeration Institute

(AHRI). The components in this system and their purposes are as follows:

1) Relief valve (Required) - Mount the relief valve on the left side of the boiler as shown in Figure 8.1 using the 1-1/4 x 4

nipple, 1-1/4 x 3/4 reducing elbow and 3/4 x close nipple provided. The relief valve shipped with the boiler is set to open

at 30 psi. This valve may be replaced with one having a pressure up to the “Maximum Allowable Working Pressure”

shown on the rating plate. If the valve is replaced, the replacement must have a relief capacity in excess of the DOE

heating capacity for the boiler.

Pipe the discharge of the relief valve to a location where water or steam will not create a hazard or cause property damage

if the valve opens. The end of the discharge pipe must terminate in an unthreaded pipe. If the relief valve discharge is

not piped to a drain it must terminate at least 6 inches above the oor. Do not run relief valve discharge piping through an

area that is prone to freezing. The termination of the relief valve discharge piping must be in an area where it is not likely

to become plugged by debris.

If necessary, the relief valve may be installed in the supply piping as shown in Figure 8.2. When this is done, the relief

valve must be as close to the boiler supply tapping as possible with no intervening shut-o valves.

2) Circulator (Required) - The circulator is shipped loose with the boiler. Fittings are provided to mount it on the boiler

return as shown in Figure 8.3, however it can be installed on the boiler supply. If the circulator is moved to the supply it

should be positioned just downstream of the expansion tank as shown in Figure 8.3.

3) Expansion Tank (Required) - If this boiler is replacing an existing boiler with no other changes in the system, the

old expansion tank can generally be reused. If the expansion tank must be replaced, consult the expansion tank

manufacturer’s literature for proper sizing.

4) Fill Valve (Required) - Either a manual or automatic ll valve may be used. The ideal location for the ll is at the

expansion tank.

15

5) Automatic Air Vent (Required) - At least one automatic air vent is required. Manual vents will usually be required in

other parts of the system to remove air during initial ll.

6) Low Water Cut-O (Required in some situations) - A low water cuto (LWCO) is required when the boiler is installed

above radiation. In addition, some codes such as ASME CSD-1 require low water cutos. Codes may also require that

this low water cuto have a manual reset function. The low water cuto may be a oat type or probe type, but must be

designed for use in a hot-water system. The low water cuto should be piped into the boiler supply just above the boiler

with no intervening valves between it and the boiler.

Crown LWCO kit PN 761000 is designed to be mounted in the boiler supply piping immediately adjacent to the boiler and

to plug directly into the factory low voltage wiring. If using a eld supplied LWCO, use a LWCO that breaks the 120VAC

supply to the boiler. Do not attempt to wire a eld-supplied 24VAC LWCO into the factory wiring.

FIGURE 8.1: STANDARD RELIEF VALVE POSITION

FIGURE 8.3: STANDARD BOILER PIPING

FIGURE 8.2: ALTERNATE RELIEF VALVE POSITION

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7) Manual Reset High Limit (Required by some codes) - This control is required by ASME CSD-1 and some other codes.

Install the high limit in the boiler supply piping just beyond the boiler with no intervening valves. Set the manual reset

high limit as far above the operating limit setting as possible, but not over 240°F. Wire the control to break the 120 VAC

electrical supply to the boiler.

8) Flow Control Valve (Required under some conditions) - The ow control valve prevents ow through the system unless

the circulator is operating. A ow control valve may be necessary on converted gravity systems to prevent gravity

circulation. Flow control valves are also used to prevent ow in circulator zone systems through zones that are not calling

for heat.

9) Isolation Valves (Optional) - Isolation valves are useful if the boiler must be drained, as they will eliminate having to drain

and rell the entire system.

10) Drain Valve - The drain valve is shipped in the boiler parts bag. Install it in the tee under the circulator as shown in

Figure 11b.

Piping for Special Situations

Certain types of heating systems have additional requirements. Some of the more common variations follow:

1) “Left Piped” Boilers – If necessary, the supply and return may be connected to the left side of the boiler by moving the

1-1/4” plug and the relief valve ttings from the tappings in the left side of the boiler to the corresponding tappings on the

right. Both the supply and return connections must be made on the same side of the boiler.

2) Indirect Water Heaters - Figure 8.4 shows typical indirect water heater piping. Boiler piping is the same as for any two-

zone system. Figure 8.4 shows circulator zoning, which is usually preferred for indirect water heaters. Size the circulator

and indirect water heater piping to obtain the boiler water ow through the indirect water heater called for by the indirect

water heater manufacturer.

3) Large Water Volume Systems - The piping shown in Figure 8.5 will minimize the amount of time that the boiler operates

with return temperatures below 120°F on these systems. A bypass is installed as shown to divert some supply water

directly into the return water. The bypass pipe should be the same size as the supply. The two throttling valves shown are

adjusted so that the return temperature rises above 120°F during the rst few minutes of operation. A three-way valve can

be substituted for the two throttling valves shown. If the circulator is mounted on the supply, the bypass must be on the

discharge side of the circulator.

FIGURE 8.4: INDIRECT WATER HEATER BOILER SIDE PIPING

17

FIGURE 8.5: BOILER BYPASS PIPING

FIGURE 8.6: ISOLATION OF BOILER FROM SYSTEM WITH A HEAT EXCHANGER

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4) Low Temperature Systems - Some systems, such as radiant tubing systems, require the system water temperature to

be limited to a value below the temperature of the water leaving the AWR. These systems also typically have return

temperatures well below the 120°F minimum.

Figure 8.6 illustrates the use of a heat exchanger to connect the AWR boiler to this type of system. The heat exchanger

will permit the transfer of heat from the boiler water to the low temperature system while holding the system supply and

boiler return temperatures within their limits. For this system to work properly the heat exchanger must be properly sized

and the correct ow rates are required on either side of the heat exchanger. Consult the heat exchanger manufacturer for

sizing information. The water in the boiler is completely isolated from the water in the system. This means that separate

ll and expansion tanks are required for the heating system loop.

There are several other ways to connect low temperature systems to the non-condensing boilers like the AWR, such as

four way mixing valve and variable speed injection Circulating systems.

5) Systems containing oxygen - Many hydronic systems contain enough dissolved oxygen to cause severe corrosion damage

to a cast iron boiler such as the AWR. Some examples include:

• Radiant systems that employ tubing without an oxygen barrier.

• Systems with routine additions of fresh water.

• Systems which are open to the atmosphere.

If the boiler is to be used in such a system, it must be separated from the oxygenated water being heated with a heat

exchanger as shown in Figure 8.6.

Consult the heat exchanger manufacturer for proper heat exchanger sizing as well as ow and temperature requirements.

All components on the oxygenated side of the heat exchanger, such as the Circulator and expansion tank, must be

designed for use in oxygenated water.

6) Piping with a Chiller - If the boiler is used in conjunction with a chiller, pipe the boiler and chiller in parallel as shown in

Figure 8.7. Use isolation valves to prevent chilled water from entering the boiler.

7) Air Handlers - Where the boiler is connected to air handlers through which refrigerated air passes, use ow control valves

in the boiler piping or other automatic means to prevent gravity circulation during the cooling cycle.

FIGURE 8.7: BOILER PIPING WITH CHILLER

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Crown Boiler AWR175 Installation guide

Crown Boiler AWR175 Installation guide

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