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 qualied
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 axed 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. Specications ......................................................................................... 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 Specications
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 Sux N for Natural Gas or Sux 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 congured for the correct gas (natural or LP).
5) Boilers built for installations at altitudes above 2000 ft. require dierent main burner orice. Make sure that the boiler is
congured 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 dicult 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
Sucient 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 inltration (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 specically for this purpose.
Mechanical Combustion Air Supply – Combustion air is brought into the room from outdoors using a blower system that is
engineered specically 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 inl-
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 eect 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 eect 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 specically 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 aect 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 modication 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 deciencies 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.
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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 cutos. 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 rell 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
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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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