Crown Boiler FWZ060 User manual

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FWZ Series
Oil-Fired Hot Water Boilers
INSTALLATION INSTRUCTIONS
These instructions must be afxed on or adjacent to the boiler
Models:
• FWZ060
• FWZ080
• FWZ100
• FWZ130
• FWZ160
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 oil
supplier. Read these instructions
carefully before installing.
DESIGNED TO LEAD
Manufacturer of Hydronic Heating Products
P.O. Box 14818 3633 I. Street
Philadelphia, PA 19134
www.crownboiler.com

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1
FOLLOW ALL INSTRUCTIONS and warnings
printed in this manual and posted on the boiler.
INSPECT THE BOILER, BURNER AND
CONTROLS 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 latest editions of the
Installation of Oil Burning Equipment ANSI/NFPA
31 in the USA or CAN/CSA B139, Installation Code
for Oil Burning Equipment in Canada.
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

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Table of Contents
I. Product Description ............................................................................... 3
II. Specications ......................................................................................... 3
III. Before Installing .................................................................................... 5
IV. Field Assembly ...................................................................................... 6
V. Locating the Boiler ................................................................................ 7
VI. Air for Combustion & Ventilation ......................................................... 8
VII. Venting ................................................................................................... 13
VIII. System Piping ........................................................................................ 15
IX. Fuel Line Piping .................................................................................... 20
X. Wiring .................................................................................................... 23
XI. Start-Up & Checkout ............................................................................. 27
XII. Operation ............................................................................................... 30
XIII. Service & Maintenance .......................................................................... 36
XIV. Troubleshooting ..................................................................................... 39
XV. Parts ....................................................................................................... 44

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I Product Description
The FWZ series boiler is a cast iron oil-red water boiler designed for use in closed forced circulation heating systems. This
boiler must be vented by natural draft into a lined masonry or metal chimney, or Type L vent. An adequate supply of air for
combustion, ventilation and dilution of ue gases must be available in the boiler room.
II Specications
TABLE 2.0: GENERAL SPECIFICATIONS
BOILER
MODEL
DIMENSIONS WATER
CONTENT
(GAL)
HEAT TRANSFER
SURFACE AREA
(SQ FT)
SHIPPING
WEIGHT
(LBS)
‘A’ ‘B’ ‘C’
FWZ060 16-1/4” 24” 5” 7.70 13.29 430
FWZ080 16-1/4” 24” 5” 7.70 13.29 430
FWZ100 22-1/4” 24” 6” 11.08 20.29 545
FWZ130 28-1/4” 30” 6” 14.46 27.29 658
FWZ160 34-1/4” 36” 7” 17.84 34.29 771
Maximum working pressure, Water - 50psi
TABLE 2.1: RATING DATA
BOILER
MODEL
BURNER
INPUT HEATING
CAPACITY
(MBH)
AHRI NET
RATING
(MBH)
MINIMUM CHIMNEY
REQUIREMENTS AFUE %
GPH MBH ROUND
IN. DIA.
SQUARE.
TILE SIZE
HEIGHT
FT.
FWZ060 0.60 84 73 63 6 8 X 8 15 86.0
FWZ080 0.80 112 97 84 6 8 X 8 15 86.3
FWZ100 1.00 140 123 107 6 8 X 8 15 87.0
FWZ130 1.30 182 160 139 7 8 X 8 15 87.1
FWZ160 1.60 222 197 171 7 8 X 8 15 87.1
Burner Capacity Rating, GPH is based on #2 fuel oil with a Gross Heating Value equal to 140,000 BTU/Gal.
Net Ratings are based on piping and pick-up allowances of 1.15

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19"
BURNER SWING
DOOR CLEARANCE
(FULLY OPEN)
21 3
8"
COLLAR
'C' DIA.
12" MIN.
REAR
SERVICE
CLEARANCE
'B' MIN.
FRONT SERVICE
CLEARANCE
(FLUEWAY CLEANING)
RIGHT VIEW
TOP VIEW
ARRANGEMENT.
REAR VIEWFRONT VIEW
*NOTE: THIS DIMENSION INCREASES AND
IS CONTROLLED BY SMOKEPIPE
*
BECKETT AFG
PORT
GAUGE
BURNER
FLOOR
TEMP/PRESSURE
LINE
RELIEF
BURNER
OBSERVATION
FLAME
DOOR
SWING
VALVE
1-1/2" FPT
SUPPLY PIPING
CONNECTION
31 1
2"
"
4 3
20
4 3
8"
CLEAN OUT
SMOKEBOX
COLLAR
DRAIN VALVE
PIPING
COVER
1-1/2"
RETURN
CIRCULATOR
SPANNER BAR
AQUASTAT
RELAY
'A'
* Circulator Supplied Loose - May Be Installed On Supply Or Return.
FIGURE 2.3: GENERAL CONFIGURATION *

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Power (“Side Wall”) Venting - Important Note
Two problems arise when any oil-fired appliance is power vented:
• There is sometimes an accelerated rate of soot buildup on the oil burner cad-cell, spinner etc.
• There is a potential for severe damage to the side of the structure in the event that the boiler
operates at a high smoke level. This can happen for many reasons, some of which are out of the
control of both the installer and appliance manufacturer.
Crown Boiler Company recommends the use of a chimney to vent the FWZ series boilers. If
a power venter must be used, it is the responsibility of the installer and power vent manufacturer to
“engineer” the power vent system. Crown Boiler Company will assume no responsibility for damage
to siding, etc. from a power vented oil-fired boiler. This applies regardless of the cause of the sooting.
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 latest
edition of Installation of Oil Burning Equipment (ANSI/NFPA31). Installations in Canada comply with the requirements
of CSA B139-04 – Installation Code for Oil-burning Equipment.
• Where required by the authority having jurisdiction, this installation must conform to the latest edition of Standard for
Controls and Safety Devices for Automatically Fired Boilers (ANSI/ASME CSD-1).
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 ANSI/NFPA31 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 re-
quired 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 instructions for
boiler output requirements.
4) In some cases, boilers installed at altitudes above 2000ft may require a different burner conguration from that at sea level.
Consult the local Crown representative for more information.

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IV Field Assembly
This boiler is shipped in two pieces:
a) The crated boiler itself with the following loose parts either packed in the combustion chamber or glued to the skid:
• Barometric Draft Regulator (if supplied)
• Circulator (if supplied)
• Relief valve
• Pipe Fittings
b) The burner carton consisting of the following items:
• Oil Burner assembly
• 2nd Pass bafes (FWZ080 only)
WARNING
Installation of burners on the FWZ other than those provided by Crown, and marked for use with this
boiler, may result in unreliable operation, property damage, personal injury, or loss of life.
It is recommended that the boiler be moved to its nal location before the items in the burner carton are installed. To complete
eld assembly:
1) Make sure that the burner carton supplied is the correct one for the boiler. The crate tag on the boiler lists the Crown part
numbers for the burner cartons that may be used with it.
2) Remove the burner mounting bolts and washers from the front door. Make sure that the burner gasket is in place and undam-
aged and mount the burner to the door as shown in Figure 4.0.
3) Plug the burner cord into the receptacle on the lower right front corner of the boiler.
4) The FWZ080 uses a pair of second pass bafes which are included in the burner carton and which must be installed in the
eld. Install these as shown in Figure 4.0. All bafes are factory installed on other models.
5) Install the barometric draft regulator, and other piping/trim, as described in the Venting and Piping sections of this manual.
FIGURE 4.0: BOILER FIELD ASSEMBLY

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V Locating the Boiler
FIGURE 5.0: CLEARANCES
WARNING
Failure to observe the following location requirements could result in property damage, a fire,
explosion or carbon monoxide (CO) hazard.
1) Clearances:
• Observe the minimum clearances shown below. Except as noted, these clearances apply to all combustible construction,
as well as noncombustible walls, ceilings and doors. Also see Figure 5.0.
Front - 24” (from front Jacket surface)
Left Side – 6”
Right Side – 6”
Rear – 12”
Top – 6”
Single Wall Chimney Connector (to combustible construction) - 18”
• A 24” service clearance is recommended above the top of the boiler, as well as on the side to which the burner swing
door opens (the left side as the boiler is shipped). See also dimension ‘B’ in Table 2.0 for recommended service clear-
ances to the front of the boiler. These clearances may be reduced to those shown above; however, servicing the boiler
will become increasingly difcult as these clearances are reduced.

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VI Air for Combustion and Ventilation
Sufcient fresh air must be supplied for combustion and ventilation. Provisions for combustion and ventilation air for oil
burning equipment must be made in accordance with the Standard for the Installation of Oil Burning Equipment (ANSI/NFPA
31).
To ensure an adequate supply of air for combustion, ventilation and ue gas dilution, start by determining whether adequate
combustion and ventilation air can be obtained through natural inltration (air leaking into the building through cracks around
windows, doors, etc). Examples of construction features which could prevent adequate natural inltration include:
• Walls and ceilings exposed to outside atmosphere having a continuous water vapor retarder with a rating of 1 perm or
less with openings gasketed and sealed
• Weather stripping added on openable windows and doors
• Caulking and sealants are applied to areas such as joints around window and door frames, between sole plates and oors,
between wall-ceiling joints, between wall panels, at penetrations for plumbing, electrical, and gas lines, and at other
openings.
• Large exhaust fans
In this manual, buildings where natural inltration will not provide adequate air for combustion, and ventilation are referred to
as “buildings of unusually tight constuction”. If in doubt, assume that the building in which the boiler is installed is of unusually
tight construction.
1) Do not install this boiler directly on a combustible oor. Where it is desired to install an FWZ on a non-carpeted combustible
oor, install the boiler on a base constructed as shown in Figure 5.1
2) If listed Type L vent is used, follow vent pipe manufacturer recommendations for minimum clearances.
3) Do not install this boiler in a location where gasoline or other ammable vapors or liquids will be stored or used. Do not
install this boiler in an area where large amounts of airborne dust will be present, such as a workshop.
FIGURE 5.1: INSTALLATION OVER A COMBUSTIBLE FLOOR

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A. For Buildings of Other than Unusually Tight Construction
1) Determine whether the boiler is to be installed in a conned space - A conned space is dened as having a volume less
than 50 cubic feet per 1000 BTU/hr input of all appliances installed in that space. To determine whether the boiler room is a
conned space:
a) Total the input of all appliances in the boiler room in thousands of BTU/hr. Round the result to the next highest 1000
BTU/hr.
b) Find the volume of the room in cubic feet. The volume of the room in cubic feet is:
Length (ft) x width (ft) x ceiling height (ft)
In calculating the volume of the boiler room, consider the volume of adjoining spaces only if no doors are installed
between them. If doors are installed between the boiler room and an adjoining space, do not consider the volume of the
adjoining space, even if the door is normally left open.
c) Divide the volume of the boiler room by the input in thousands of BTU/hr. If the result is less than 50, the boiler room is
a conned space.
Example:
An FWZ080 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:
Input of FWZ080 = 0.80 Gal/hr x 140000 BTU/Gal = 112000BTU/hr
Total input in thousands of BTU/hr = (112000 BTU/hr + 30000 BTU/hr)/1000 = 142
Volume of room = 6.25 ft x 7 ft x 8 ft = 350 ft3
350/142 = 2.46. Since 2.46 is less than 50, the boiler room is a conned space.
2) Unconned Space - Natural inltration into the boiler room will normally provide adequate air for combustion and ventila-
tion without additional louvers or openings into boiler room.
3) Conned Space - 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 6.0).
• Each opening must have a free area of 1 square inch per 1000 BTU/hr input of all fuel 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 effect of mesh, grills, and louvers. Where screens are
used, they must be no ner than ¼” (4 x 4) mesh.
B. For Buildings of Unusually Tight Construction
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 6.1, Figure 6.2, and Figure 6.3) - Each opening must have a free
cross sectional area of 1 square inch per 4000 BTU/hr of the total input of all fuel red appliances in the boiler room but
not less than 100 square inches. Minimum opening size is 3 inches.
• Openings to outdoors via horizontal ducts (Figure 6.4) - Each opening must have a free cross sectional area of 1 square
inch per 2000 BTU/hr of the total input of all fuel red appliances in the boiler room but not less than 100 square inches.
Minimum opening size is 3 inches.
• The “free area” of an opening takes into account the blocking effect of mesh, grills, and louvers. Where screens are
used, they must be no ner than ¼” (4 x 4) mesh.

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FIGURE 6.0: BOILER INSTALLED IN CONFINED SPACE, ALL AIR FROM INSIDE
FIGURE 6.1: ALL AIR FROM OUTDOORS, VENTILATED CRAWL SPACE AND ATTIC

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FIGURE 6.2: ALL AIR FROM OUTDOORS, VIA VENTILATED ATTIC
FIGURE 6.3: ALL AIR FROM OUTDOORS, USING OPENINGS INTO BOILER ROOM

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FIGURE 6.4: ALL AIR FROM OUTDOORS, USING HORIZONTAL DUCTS INTO BOILER ROOM

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VII Venting
The vent installation must be in accordance with local building codes, or the local authority having jurisdiction. Contact your
local re and building ofcials on specic requirements for restrictions and the installation of fuel oil burning equipment. In
the absence of other applicable codes, the vent system installation must meet the requirements of NFPA 31 – Standard for the
Installation of Oil-Burning Equipment and NFPA 211 - Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning
Appliances. Vent systems in Canada must comply with CSA B139-04 – Installation Code for Oil-burning Equipment.
A typical vent system is illustrated in Figure 7.0. The components of the vent installation are the vent connector (breeching),
barometric draft regulator, and chimney.
1) Acceptable Chimneys - The following chimneys may be used to vent a FWZ series boiler:
• Listed Type L 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 the latest edition of Standard for
Chimneys, Fireplaces, Vents, and Solid Fuel Burning Appliances (NFPA 211) and lined with a clay liner or other listed
lining system. Do not vent a FWZ series boiler into an unlined chimney.
2) Acceptable Vent Connectors - The following may be used for vent connectors:
• Listed Type L vent.
• Single Wall Galvanized Pipe - Use 0.018” (26 gauge) or heavier.
3) Chimney and Vent Connector Sizing - See Table 7.1 for minimum vent connector and chimney sizing. The vent connector
size must not be smaller than boiler ue collar diameter.
4) Do not vent this appliance into any portion of a mechanical vent system operating under positive pressure.
5) Do not connect the boiler into a chimney ue serving an open replace or other solid fuel appliance.
6) Prior to boiler installation, an existing chimney must be inspected by a qualied person in accordance with the requirements
of Chapter 11 of NFPA 211, Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances. This inspection is
intended to identify safety problems with the chimney such as obstructions, a missing or damaged liner, or leak points. Clean
chimney as necessary and correct any other chimney defects before installing the boiler.
7) Vent connector must slope upward from boiler not less than one inch in four feet. No portion of vent pipe should run
downward or have sags. Vent connector must be securely supported.
8) The vertical section of vent connector coming off 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 (7) above.
9) Vent connector must be installed above the bottom of the chimney to minimize risk of blockage.
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.
• Inspect existing chimney before installing boiler. Failure to clean or replace damaged pipe
or tile lining will cause property damage, severe personal injury or death.
• Do not de-rate the appliance. Failure to fire the unit at it’s designed input may cause
excessive condensation upon the interior walls of the chimney. In addition, the lower input
may not create enough draft to adequately evacuate the products of combustion.

14
10) Vent connector must be inserted ush with inside face of the chimney liner and the space between vent connector and
chimney sealed tight. A thimble permanently cemented in place can be used to facilitate removal of vent connector for
cleaning.
11) Install the barometric draft regulator supplied with this boiler in accordance with the regulator manufacturer’s instructions.
No other draft regulator shall be used. Mount the barometric draft regulator in the side connection of a tee (not supplied).
12) Secure all joints in the vent connector system with sheet metal screws. This includes the joint between the vent connector and
the boiler collar (see Figure 7.0, Detail ‘A’), as well as the barometric draft regulator. Use at least three screws at each joint.
FIGURE 7.0: TYPICAL VENT SYSTEM INSTALLATION AND COMPONENTS
TABLE 7.1: MINIMUM RECOMMENDED BREECHING AND CHIMNEY SIZE
BOILER
MODEL
MINIMUM
BREECHING
DIA. (INCHES)
MINIMUM CHIMNEY REQUIREMENTS
ROUND I.D.
(IN.)
SQUARE. TILE
SIZE (NOMINAL) HEIGHT (FT.)
FWZ060 5 6 8 X 8 15
FWZ080 5 6 8 X 8 15
FWZ100 6 6 8 X 8 15
FWZ130 6 7 8 X 8 15
FWZ160 7 7 8 X 8 15

15
VIII System Piping
WARNING
• Install boiler so that the electrical 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 135°f can cause severe
boiler or chimney damage.
• Do not operate this boiler at a flow rate less than the minimum shown in Table 8.0,
Column (a).
• 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.
A. Standard Piping
Figure 8.2 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 rear of the boiler as shown in Figure 8.1 using the ttings 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 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.
2) Return Injector Pipe - The return injector distributes water evenly throughout the heat exchanger and also helps to minimize
the possibility of thermal shock. Install it in the upper-rear tapping as shown in Figure 8.1. The 2 x 1-1/2” reducing elbow can
be oriented in any direction.
3) Circulator (Required) - Figure 8.2 shows the ideal location of the circulator which is in the supply piping immediately
downstream of the expansion tank. A less ideal, but acceptable, location for most residential circulators is in the return. The
circulator/s and connected piping should be sized so that the temperature rise across the boiler is 20F. Burner operation while
the ow through the boiler is less than that shown in Table 8.0, column (a) could result in problems regulating the supply
temperature. If the system is zoned, the ow rate through the boiler should be greater than that shown in Table 8.0 when only
the zone having the lowest ow rate is on. If this requirement cannot otherwise be met, use a bypass, or primary-secondary
piping. Boiler head loss data at the minimum ow and the ow corresponding to a 20F rise are shown in Table 8.0.
4) Expansion Tank (Required) - If this boiler is replacing an existing boiler with no other changes in the system, the old

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Table 8.0 Minimum Flow Rate Requirements
Model
Minimum Flow
(Approx 35F Rise) Flow at 20F Rise
(a) (c) (d) (e)
Min. Flow
(Gal /Min)
Boiler Head
Loss (ft w.c.)
Flow
(GPM)
Boiler Head
Loss (ft w.c.)
FWZ060 4.5 0.10 7.3 0.22
FWZ080 6.0 0.16 9.7 0.38
FWZ100 8.0 0.27 12.3 0.61
FWZ130 10.0 0.42 16.0 0.88
FWZ160 12.0 0.61 19.7 1.45
expansion tank can generally be reused. If the expansion tank must be replaced, consult the expansion tank manufacturer’s
literature for proper sizing.
5) Fill Valve (Required) - Either a manual or automatic ll valve may be used. The ideal location for the ll is at the expansion
tank.
6) 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.
7) Low Water Cut-Off (Required in some situations) - A low water cut-off is required when the boiler is installed above
radiation. In addition, some codes such as ASME CSD-1, require low water cut-offs. Codes may also require that this low
water cut-off have a manual reset function. The low water cut-off may be a oat type or probe type, but must be designed
for use in a hot-water system. The low water cut-off should be piped into the boiler supply just above the boiler with no
intervening valves between it and the boiler. Use a low water cut-off that breaks the 120 VAC supply to the boiler. Do not
attempt to wire a 24-volt low water cut-off into the boiler factory wiring.
8) 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.
9) 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 “ghost ows” in circulator zone systems through zones that are not calling for
heat.
10) 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.
11) Drain Valve - The drain valve is shipped in the boiler parts bag. Install it in the bottom-rear of the boiler return as shown in
Figure 8.1.
B. Piping for Special Situations

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FIGURE 8.1: INSTALLATION OF FACTORY SUPPLIED PIPING
FIGURE 8.2: STANDARD BOILER PIPING

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FIGURE 8.3: INDIRECT WATER HEATER BOILER SIDE PIPING
Certain types of heating systems have additional requirements. Some of the more common variations follow:
1) Indirect Water Heaters - Figure 8.3 shows typical indirect water heater piping. Boiler piping is the same as for any two zone
system. Figure 8.3 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.
2) Large Water Volume Systems - The piping shown in Figure 8.4 will minimize the amount of time that the boiler operates
with return temperatures below 135°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 135°F during the rst few minutes of operation. A three-way valve can be substituted
for the two throttling valves shown. A bypass can also be used to ensure that the minimum ow requirement in Table 8.0 is
met.
3) Systems Containing Oxygen - Many hydronic systems contain enough dissolved oxygen to cause severe corrosion damage to
a cast iron boiler such as the FWZ. 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 8.5. 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 pump and expansion
tank, must be designed for use in oxygenated water.
4) 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.