Page 1
WARNING: If the information in
this manual is not followed exactly, a fire
or explosion may result causing property
damage, personal injury or loss of life.
-- This water heater MUST NOT be installed
in any location where gasoline or flammable
vapors are likely to be present.
CBX-CWX-I-S Rev A
Installation & Service Manual
Models: 497 - 2067
-- WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electric switch; do not
use any phone in your building.
• Immediately call your gas supplier from a
near by phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call
the fire department.
• Installation and service must be performed
by a qualified installer, service agency, or
the gas supplier.
WARNING:
This manual supplies information for the
installation, operation, and servicing of the
appliance. It is strongly recommended that this
manual be reviewed completely before proceeding
with an installation. Perform steps in the order
given. Failure to comply could result in severe
personal injury, death, or substantial property
damage.
Save this manual for future reference.
Page 2
Contents
HAZARD DEFINITIONS ..................................................... 2
PLEASE READ BEFORE PROCEEDING ...................... 3-4
SAFETY INFORMATION ................................................... 4
THE COPPER-FIN -- HOW IT WORKS.......................... 5-7
RATINGS ........................................................................ 8-9
1. DETERMINE UNIT LOCATION
Locating the Unit .............................................................. 10
Indoor Clearances from Combustible Construction ........ 10
Freeze Protection ........................................................ 11-12
Prevent Combustion Air Contamination ...................... 11-13
Combustion Air Options .............................................. 14-15
2. VENTING
General Venting Information ....................................... 16-17
Vent System Options
Conventional Negative Draft Venting .................... 18-19
Masonry Chimney Installation and Inspection ............ 19
Outdoor Installation Options .................................. 20-21
3. GAS CONNECTIONS
Connecting to Gas Supply ............................................... 22
Gas Pressure Test ........................................................... 22
Gas Piping ........................................................................ 22
Gas Connections / Gas Train and Controls ..................... 23
Combination Gas Valves .................................................. 24
Checking Gas Supply Pressure .................................. 24-25
Gas Manifold Pressure Adjustment ............................ 25-26
4. WATER CONNECTIONS
Inlet & Outlet Connections ............................................... 27
Relief Valve ...................................................................... 27
Heating Boiler Installations .......................................... 27-29
Low Temperature Return Water Systems ........................ 30
Primary/Secondary Piping of a Single Boiler .............. 31
Primary/Secondary Piping of Multiple Boilers ............ 32
Boiler w/Low Temperature Bypass Piping .................. 33
Primary/Secondary Piping with Buffer Tank ............... 34
Installation with a Chilled Water System .......................... 35
Typical Heating Boiler Installations .................................. 35
Boiler Flow Rate / Bypass Requirements ................... 35-36
Temperature/Pressure Gauge and Water Treatment ...... 36
5. ELECTRICAL CONNECTIONS
Connecting to Electrical Supply ....................................... 37
EMS Connections ............................................................ 38
Terminal Strip Connection Options .................................. 38
Temperature Controls
Temperature Adjustment ............................................ 39
Outdoor Reset Option ................................................. 40
Temperature Control Sensors ............................... 41-42
Hot Surface Ignition System ....................................... 42-43
Operation and Diagnostic Lights ...................................... 44
6. STARTUP
Operating and Safety Instructions .................................... 45
Check Water Chemistry ................................................... 46
Freeze Protection (when used) ........................................ 46
Fill and Test Water System .............................................. 46
Purge Air from Water System .......................................... 46
Check for Gas Leaks / Thermostat Circuit(s) ................... 47
Check Vent and Air Piping ............................................... 47
Placing the Boiler in Operation ........................................ 47
7. DOMESTIC WATER HEATERS
General ............................................................................. 48
Water Velocity Control ..................................................... 48
Pipe Size Requirements
Typical Water Heater Piping w/ Storage Tank ........... 49
Single Water Heater Piping w/Two Storage Tanks ... 50
Multiple Water Heater Piping w/One Storage Tank ... 51
Multiple Water Heater Piping w/Multi. Storage Tanks .52
Water Chemistry............................................................... 53
Circulating Pump/ Performance ....................................... 53
Heat Exchanger ............................................................... 54
Potable Hot Water Temperature Controls ........................ 54
Location of Cold Water Supply Piping Connections ........ 55
High Water Temperature Limit Control ............................ 56
Optional Relief Valve ........................................................ 56
Thermal Expansion and Cathodic Protection ................... 56
8. MAINTENANCE
Burner Flames .................................................................. 57
Burner Removal and Cleaning Procedures ................ 57-58
Adjusting Differential Air Pressure .............................. 58-59
Servicing a Hot Surface Igniter / Ignition Module ............ 60
Sequence of Operation Overview ............................... 60-61
9. GLOSSARY ........................................................... 62-63
10. DIAGRAMS ........................................................... 64-67
Revision Notes .................................................. Back Cover
Hazard definitions
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk
levels or to important information concerning the life of the product.
DANGER
WARNING
CAUTION
CAUTION
NOTICE
2
DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or
serious injury.
WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or
serious injury.
CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or
moderate injury.
CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not
avoided, may result in property damage.
NOTICE indicates special instructions on installation, operation, or maintenance that are important but
not related to personal injury or property damage.
Page 3
Please read before proceeding
Special instructions
Installation & Service Manual
NOTICE
WARNING
WARNING
This is a gas appliance and should be installed
by a licensed electrician and/or certified gas
supplier. Service must be performed by a
qualified service installer, service agency or
the gas supplier.
If the information in these instructions is
not followed exactly, a fire or explosion may
result causing property damage, personal
injury, or death.
This appliance MUST NOT be installed in
any location where gasoline or flammable
vapors are likely to be present, unless the
installation is such to eliminate the probable
ignition of gasoline or flammable vapors.
Improper installation, adjustment,
alteration, service or maintenance can
cause injury or property damage. Refer
to this manual for assistance or additional
information, consult a qualified installer,
service agency or the gas supplier.
Checking equipment –
Upon receiving equipment, check for signs of shipping damage.
Pay particular attention to parts accompanying the appliances
which may show signs of being hit or otherwise being
mishandled. Verify total number of pieces shown on packing
slip with those actually received. In case there is damage or a
shortage, immediately notify the carrier.
Do not use this appliance if any part has been under water.
The possible damage to a flooded appliance can be extensive
and present numerous safety hazards. Any appliance that has
been under water must be replaced.
NOTICE
REMOVAL OF COMBUSTION CHAMBER LINING OR
BASE PANELS:
Avoid breathing dust and contact with skin
and eyes.
• Use NIOSH certified dust respirator (N95).
This type of respirator is based on the OSHA
requirements for cristobalite at the time this
document was written. Other types of
respirators may be needed depending on the job
site conditions. Current NIOSH recommendations
can be found on the NIOSH website at
http://www.cdc.gov/niosh/homepage.html.
NIOSH approved respirators, manufacturers, and
phone numbers are also listed on this website.
The ceramic fiber material used in this
appliance is an irritant; when handling or
replacing the ceramic materials it is advisable
that the installer follow these safety guides.
Apply enough water to the combustion chamber
lining to prevent airborne dust.
Remove the combustion chamber lining from the
appliance and place it in a plastic bag for disposal.
• NIOSH stated First Aid:
Eye: Irrigate immediately.
Breathing: Fresh air.
WARNING
The combustion chamber insulation in this
appliance contains ceramic fiber material.
Ceramic fibers can be converted to cristobalite
in very high temperature applications.
The International Agency for Research on
Cancer (IARC) has concluded, “Crystalline
silica in the form of quartz or cristobalite
from occupational sources is carcinogenic
to humans (Group 1).” Normal operating
temperatures in this appliance are below the
level to convert ceramic fibers to cristobalite.
Abnormal operating conditions would have
to be created to convert the ceramic fibers in
this appliance to cristobalite.
The ceramic fiber material used in this
appliance is an irritant; when handling
or replacing the ceramic materials it is
advisable that the installer follow these safety
guidelines.
Warranty –
Factory warranty (shipped with unit) does not apply to units
improperly installed or improperly operated.
Experience has shown that improper installation or system
design, rather than faulty equipment, is the cause of most
operating problems.
1. Excessive water hardness causing a lime/scale build-up in
the copper tube is not the fault of the equipment and is
not covered under the manufacturer’s warranty (see
Water Treatment and Water Chemistry).
2. Excessive pitting and erosion on the inside of the copper
tube may be caused by too much water velocity through
the tubes and is not covered by the manufacturer’s
warranty (see Boiler Flow Rates and Temperature Rise for
flow requirements).
• Wear long-sleeved, loose fitting clothing, gloves,
and eye protection.
33
Page 4
Please read before proceeding
Safety information
Installation & Service Manual
Owner warning –
The information contained in this manual is intended for use
by qualified professional installers, service technicians, or gas
suppliers.
NOTICE
A gas appliance that draws combustion air from the equipment
room where it is installed must have a supply of fresh air
circulating around it during burner operation for proper gas
combustion and proper venting.
WARNING
Consult and follow all local Building and
Fire Regulations and other Safety Codes that
apply to this installation. Consult local gas
utility company to authorize and inspect all
gas and flue connections.
Should overheating occur or the gas supply
fail to shut off, do not turn off or disconnect
the electrical supply to the pump. Instead,
shut off the gas supply at a location external
to the appliance.
Prevention of freezing –
Heat exchangers and headers damaged by freezing are not
covered by warranty.
See Section 6, Startup - Freeze Protection for more information.
Codes –
The equipment shall be installed in accordance with those
installation regulations in force in the local area where the
installation is to be made. These shall be carefully followed in all
cases. Authorities having jurisdiction shall be consulted before
installations are made. In the absence of such requirements, the
installation shall conform to the latest edition of the National
Fuel Gas Code, ANSI Z223.1. Where required by the authority
having jurisdiction, the installation must conform to American
Society of Mechanical Engineers Safety Code for Controls and
Safety Devices for Automatically Fired Boilers, ASME CSD-1.
All boilers conform to the latest edition of the ASME Boiler
and Pressure Vessel Code, Section IV. Where required by the
authority having jurisdiction, the installation must comply with
the Canadian Gas Association Code, CAN/CGA-B149.1 and/
or B149.2 and/or local codes. This appliance meets the safe
lighting performance criteria with the gas manifold and control
assembly provided, as specified in the ANSI standards for gasfired hot water boilers, ANSI Z21.13 and gas water heaters,
ANSI Z21.10.3.
WARNING
1. This unit is only for use with the type of gas indicated on the
rating plate.
2. If you smell gas
• shut off gas supply
• do not try to light any appliance
• do not touch any electrical switch; do not use any phone
in your building
• immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions
• if you cannot reach your gas supplier, call the fire
department
3. Boilers and water heaters are heat producing appliances. To
avoid damage or injury, do not store materials against the
appliance or the vent-air intake system. Use proper care
to avoid unnecessary contact (especially children) with the
appliance and vent-air intake components.
4. Never cover your unit, lean anything against it, store trash
or debris near it, stand on it or in any way block the flow of
fresh air to your unit.
5. UNDER NO CIRCUMSTANCES MUST FLAMMABLE
MATERIALS SUCH AS GASOLINE OR PAINT THINNER
BE USED OR STORED IN THE VICINITY OF THIS
APPLIANCE, VENT-AIR INTAKE SYSTEM OR ANY
LOCATION FROM WHICH FUMES COULD REACH
THE APPLIANCE OR VENT-AIR INTAKE SYSTEM.
6. Appliance surfaces become hot during operation. Be careful
not to touch hot surfaces. Keep all adults, children, and
animals away from operation of the hot unit. Severe burns
can occur.
7. You must take adequate care to prevent scald injury when
storing water at elevated temperatures for domestic use.
8. This unit must have an adequate supply of fresh air during
operation for proper gas combustion and venting.
9. Make sure all exhaust venting is properly installed and
maintained. Improper venting of this unit could lead to
increased levels of carbon monoxide.
10. Do not use this boiler if any part has been under water.
Immediately call a qualified service technician to replace
the boiler. The possible damage to a flooded boiler can
be extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced.
11. Do not alter this unit in any way. Any change to this unit or
its controls can be dangerous.
To minimize the possibility of serious
personal injury, fire or damage to your
unit, never violate the following safety
rules.
4
Page 5
The Copper-fin - How it works...
Installation & Service Manual
1. Heat exchanger
The heat exchanger allows system water to flow through specially
designed tubes for maximum heat transfer. The glass lined
headers and copper fined tubing are encased in a jacket that
contains the combustion process.
2. Inner combustion chamber door
The inner combustion chamber door is a galvanized steel door which
allows access for service, maintenance, and removal of the
heat exchanger from inside the combustion chamber.
3. Blower
The blower pulls in air and injects air into the individual burners
along with gas from the gas manifold where the mix is burned in
the combustion chamber.
4. Gas valve
The gas valve allows the proper amount of gas to pass into the
burner for combustion. The gas valve is biased with pressure from
the combustion chamber to assist in regulation of the gas flow.
5. System / tank temperature sensor (not shown)
When connected, this sensor can be used as a system sensor or a
tank sensor.
6. Inlet temperature sensor
This sensor monitors inlet water temperature. If selected as
the controlling sensor, the appliance will maintain the set point
temperature based on the reading at this sensor.
7. Temperature and pressure gauge (boiler only)
The temperature and pressure gauge monitors the outlet
temperature of the appliance as well as the system water
pressure.
8. Diagnostic display
The diagnostic display consists of six (6) lamps used to show all
the major steps of operation and control malfunctions.
9. Burner
The burner is a ported stainless steel construction which uses a gas
air mix to operate at a fixed input. Banks of burners are turned on
or off to vary the firing rate.
10. Water outlet (system supply)
The water outlet is a pipe connection that supplies water to the
system with connections for a flow switch (see #25), a relief valve
(see #22), and a temperature and pressure gauge (boilers only)
(see #7).
11. Water inlet (system return)
The water inlet is a pipe connection that receives water from the
system and delivers it to the heat exchanger.
12. Gas supply pipe
The gas supply pipe on this appliance is 1 1/4'' diameter (Models
497 - 747) and 2" diameter (Models 987 - 2067) NPT. Please
reference the National Fuel Gas Code charts for connection
details.
13. Two-Stage Electronic Temperature Control
The electronic temperature control provides two-stage (high / low
fire) operation by monitoring system demand.
14. Air intake
Fresh air for combustion is drawn through a filter provided at the
air intake, located at either the rear or right side of the appliance.
15. Line voltage terminal strip
The line voltage terminal strip provides a location to connect
all of the line voltage (120 VAC) contact points to the unit.
16. Low voltage connection board
The low voltage connection board provides a location to tie in
all of the low voltage contacts to the appliance. This is where most
of the external safety devices are connected to the unit such as
the louver proving switch.
17. Front doors - upper and lower
The front doors provide access to the gas train as well as the
blower, burners and other key components for service and
maintenance.
18. Hot surface igniter (HSI)
The hot surface igniter is a device that is used to ignite the
air/gas mixture as well as monitor the performance of the flame
during operation. This device acts as a flame sense electrode.
19. Flame inspection window (sight glass)
The flame inspection windows, located on either side of the
appliance, allow for visual inspection of the burners and flame
during operation.
20. Gas shut off valve (downstream test cock)
The downstream test cock (when supplied) is in the gas train to ensure
complete shut off of the gas to the burner in case of
maintenance, inspection, or testing of the valve.
21. Manual high limit
Device that monitors the outlet water temperature to ensure
safe operation. If the temperature exceeds its setting (field
adjustable), it will break the control circuit, shutting the
appliance down.
22. Relief valve
The relief valve is a safety device that ensures the maximum
pressure of the appliance is not exceeded. Boilers operate on
pressure only and are shipped from the factory at a rating of
50 PSI. Water heaters operate on temperature and pressure and
are shipped standard as 150 PSI and 210°F (98.9°C).
23. Power switch
The power switch is used to engage and disengage power to the
appliance on the 120 VAC circuit.
24. Air pressure switch
The air pressure switch is a safety device which ensures proper
blower operation. The air pressure switch is wired in series with
the low voltage control circuit in such a way that if the fan does not
engage or shuts down prematurely the device will break the
control circuit and the unit will shut down.
25. Flow switch
The flow switch is a safety device that ensures flow through the
heat exchanger during operation. This appliance is low mass and
should never be operated without flow. The flow switch makes
contact when flow is detected and allows the unit to operate. If
flow is discontinued during operation for any reason the flow
switch will break the control circuit and the unit will shut down.
26. Drain port(s)
Location from which the heat exchanger can be drained.
27. Manual shutoff valve (not shown)
Manual valve used to isolate the unit from the gas supply.
28. Flue pipe
A pipe like enclosure that is placed over an appliance to improve
natural upward convection of heat and thereby increase the
dissipating ability of the appliance.
5
Page 6
The Copper-fin - How it works...
26
17
17
12
14
22
25
28
13
16
21
15
23
18
20
24
9
2
3
4
8
7
6
19
11
10
1
Installation & Service Manual
12
26
17
Models 497 - 747 Front View
14
17
28
22
25
Models 497 - 747 Rear View
13
16
15
18
6
23
Models 497 - 747 Right Side (inside unit)
24
21
20
10
11
19
Models 497 - 747 Left Side (inside unit)
Page 7
Installation & Service Manual
14
25
22
7
28
21
4
3
2
9
20
18
24
23
15
16
13
8
6
19
11
10
7
1
12
17
17
26
The Copper-fin - How it works... (continued)
12
26
17
14
28
25
22
17
Models 987 - 2067 Front View
21
13
16
15
23
Models 987 - 2067 Rear View
24
18
20
Models 987 - 2067 Right Side (inside unit)
10
Models 987 - 2067 Left Side (inside unit)
11
19
7
Page 8
Ratings
HIGH ALTITITUDE
LABEL
Installation & Service Manual
Copper-fin
I=B=R Rating
Model Number
Note: Change “N” to
“L” for L.P. gas models.
CBN497 250 495 401 349
CBN647 350 645 522 454
CBN747 350 745 603 524
CBN987 360 985 798 694
CBN1257
CBN1437
CBN1797
CBN2067
NOTICE
Input MBH
(Note 4)
Min Max
720 1255 1017 884
720 1435 1162 1010
720 1797 1454 1264
990 2065 1673 1455
Maximum allowed working pressure is located on the rating plate.
Gross
Output
MBH
(Note 1)
Net
I=B=R
Ratings
Water,
MBH
(Note 2)
Other Specifications
Boiler Water
Content
Gallons
1.7 2" 1 1/4" 6"
2.0 2" 1 1/4" 8"
2.1 2" 1 1/4" 8"
2.2 2 1/2" 2" 10"
2.6 2 1/2" 2" 12"
2.9 2 1/2" 2" 12"
3.3 2 1/2" 2" 14"
3.6 2 1/2" 2" 14"
Water
Connections
Gas
Connections
Vent Size
(Note 3)
Notes:
1. The ratings are based on standard test procedures prescribed
by the United States Department of Energy.
2. Net I=B=R ratings are based on net installed radiation of
sufficient quantity for the requirements of the building
and nothing need be added for normal piping and pickup.
Ratings are based on a piping and pickup allowance of 1.15.
3. Copper-fins require special gas venting. Use only the vent
materials and methods specified in the Installation and
Service Manual.
4. The Copper-fin is orificed for operation up to 2000
feet altitude. The ap pli ance will be derated 4% per 1000
feet above 2000 feet el e va tion. Consult the factory for
installations above 2000 feet elevation.
5. Ratings have been confirmed by AHRI.
8
Figure A High altitude label location_boiler
Page 9
Ratings (continued)
Model Number
Note: Change “N” to
“L” for L.P. gas models
CWN497
Installation & Service Manual
Copper-fin Specifications
Input
MBH
495 1.7 2" 1 1/4" 6"
Water
Content Gallons
Water Connections Gas Connections
Vent Size
(Note 1)
CWN647
CWN747
CWN987
CWN1257
CWN1437
CWN1797
CWN2067
NOTICE
Maximum allowed working pressure is located on the rating plate.
645 2.0 2" 1 1/4" 8"
745 2.1 2" 1 1/4" 8"
985 2.2 2 1/2" 2" 10"
1255 2.6 2 1/2" 2" 12"
1435 2.9 2 1/2" 2" 12"
1797 3.3 2 1/2" 2" 14"
2065 3.6 2 1/2" 2" 14"
Notes:
1. Copper-fins require special gas venting. Use only the vent
materials and methods specified in the Installation and
Service Manual.
2. The Copper-fin is orificed for operation up to 2000
feet altitude. The ap pli ance will be derated 4% per 1000
feet above 2000 feet el e va tion. Consult the factory for
installations above 2000 feet elevation.
HIGH ALTITUDE
LABEL
Figure B High altitude label location_water heater
9
Page 10
1 Determine unit location
Installation & Service Manual
Installation
This unit meets the safe lighting performance criteria with the
gas manifold and control assembly provided, as specifi ed in the
ANSI standards for gas-fi red units. ANSI Z21.13/CSA 4.9 and
ANSI Z21.10.3/CSA 4.3.
Locating the unit
1. Maintain all clearances from combustible construction
when locating unit. See Clearances from Combustible
Construction, this page.
2. Locate the unit so that if water connections should
leak, water damage will not occur. When such locations
cannot be avoided, install a suitable drain pan that
is well-drained under the unit. The pan must not
restrict combustion air flow. The appliance
manufacturer is not responsible for water damage in
connection with this unit, or any of its components.
3. Install indoor units so that the ignition system
components are protected from any water while
operating or during service.
4. Appliances located in a residential garage and in
adjacent spaces that open to the garage and are not
part of the living space of a dwelling unit must be
installed so that all burners and burner ignition devices
have a minimum clearance of not less
than 18'' (46cm) above the floor. The
appliance must be located or protected so that it is
not subject to physical damage by a moving vehicle.
5. DO NOT install this appliance in any location where
gasoline or flammable vapors are likely to be present.
6. The appliance must be installed on a level surface.
7. Models 497 - 747 are approved for installation on
combustible flooring using the approved combustible floor
kits (reference Table 1A). Models 987 - 2067 are approved
for installation on combustible flooring. Do not install
appliances directly on carpeting.
8. For outdoor models, you must install an optional vent
kit. Instructions for mounting the vent kit are included
in the venting section. Do not install outdoor models
directly on the ground. You must install the outdoor
unit on a concrete, brick, block, or other
non-combustible pad. Outdoor models have additional
special location and clearance requirements. See
Outdoor Installation Venting, page 20. A wind proof
cabinet protects the unit from weather.
Indoor clearances from combustible
construction
Maintain minimum specified clearances for adequate
operation. Allow sufficient space for servicing pipe
connections, pump and other auxiliary equipment, as well
as the unit. See rating plate for specific service clearance
requirements.
Right Side 3'' (7.5 cm)
Rear 3'' (7.5 cm) (3'' min. from any surface)*
Left Side 6'' (15 cm) (24'' (0.61 m) suggested for
service)
Front Alcove* (30'' (0.76m) suggested for service)
Top 3'' (7.5 cm)
Flue 1'' (25.4 mm)
Hot Water Pipes 1'' (25.4 mm)
*An Alcove is a closet without a door. Thirty-six inches (36")
to rear required for outdoor installation.
Note: No additional clearance is needed on the right side
of the unit for the observation port. An observation port is
located on both the right and left side of the unit.
Figure 1-1_Indoor clearances from combustible
construction
3"
MIN
REAR
6"
MIN
LEFT SIDE
3"
MIN
TOP
3"
MIN
RIGHT SIDE
10
30"
MIN
FRONT
Page 11
1 Determine unit location (continued)
DRAIN PLUG G (2X)
Installation & Service Manual
TABLE 1A
COMBUSTIBLE FLOOR KITS
Model Kit Number
497 CFK3302
647 CFK3303
747 CFK3304
Freeze protection
Although these units are CSA International designcertifi ed for outdoor installations, such installations are not
recommended in areas where the danger of freezing exists. You must
provide proper freeze protection for outdoor installations, units
installed in unheated mechanical rooms or where temperatures
may drop to the freezing point or lower. If freeze protection is
not provided for the system, a low ambient temperature alarm is
recommended for the mechanical room. Damage to the unit by
freezing is non-warrantable.
Anytime the temperature measured at any of the sensors
(except the outside air temperature sensor) drops below 40°F, the
control turns on the pump contact and the alarm relay. The
pump will shut off when both sensors are above 50°F.
Outdoor boiler installation
Adequate hydronic system antifreeze must be used. A snow
screen should be installed to prevent snow and ice accumulation
around the unit or its venting system.
Shut-down and draining
If for any reason, the unit is to be shut off, the following
precautionary measures must be taken:
1. Shut off gas supply.
2. Shut off water supply.
3. Shut off electrical supply
4. Drain the unit completely. Remove one threaded plug
or bulbwell from the inlet side of the front header and
one from the outlet side of the front header on the heat
exchanger. Blow all water out of the heat exchanger
(see FIG.'s 1-2A and 1-2B).
5. Drain pump and piping.
Figure 1-2A_Drain the unit_Models 497 - 747
Pump operation
This unit is equipped with a pump delay of 30 seconds. If
continuous operation of the pump is desired, the pump must
be electrically connected to another circuit. Connection of
the pump to this unit will provide intermittent pump delay
operation.
Location
Locate indoor boilers and water heaters in a room having a temperature safely above freezing [32°F (0°C)].
CAUTION
A mechanical room operating under a negative
draft pressure may experience a down draft
in the flue of a boiler when it is not firing.
The cold outside air pulled down the flue
may freeze a heat exchanger. This condition
must be corrected to provide adequate freeze
protection.
Hydronic systems anti-freeze
Freeze protection for a heating boiler or hot water supply boiler
using an indirect coil can be provided by using hydronic system
antifreeze. Follow the appliance manufacturers instructions. Do
not use undiluted or automotive type antifreeze.
DRAIN PLUG
Figure 1-2B_Drain the unit_Models 987 - 2067
DR
11
Page 12
1 Determine unit location
Installation & Service Manual
Freeze Protection for a Heating Boiler
System (if required)
WARNING
1. Use only properly diluted inhibited glycol
anti-freeze designed for hydronic systems. Inhibited
propylene glycol is recommended for systems where
incidental contact with drinking water is possible.
2. A solution of 50% antifreeze will provide
maximum protection of approximately -30°F.
3. Follow the instructions from the antifreeze
manufacturer. Quantity of antifreeze required is
based on total system volume including
expansion tank volume.
4. Glycol is denser than water and changes
the viscosity of the system. The addition
of glycol will decrease heat transfer and
increase frictional loss in the boiler and
related piping. A larger pump with more
capacity (15% to 25% more) may be required
to maintain desired fl ow rates and
prevent a noise problem in a glycol system.
Do not use undiluted or automotive type
anti-freeze.
Combustion and Ventilation Air
Provisions for combustion and ventilation air must be
in accordance with Section 5.3, Air for Combustion and
Ventilation, of the latest edition of the National Fuel Gas Code,
ANSI Z223.1, in Canada, the latest edition of CAN/CGA-B149
Installation Code for Gas Burning Appliances and Equipment,
or applicable provisions of the local building codes.
Provide properly-sized openings to the equipment room to
assure adequate combustion air and proper ventilation when
the unit is installed with conventional venting or sidewall
venting.
*Outside air openings shall directly communicate with the
outdoors. When combustion air is drawn from the outside
through a duct, the net free area of each of the two openings
must have twice (2 times) the free area required for Outside
Air/2 Openings. The above requirements are for the boiler
only; additional gas fired appliances in the equipment room
will require an increase in the net free area to supply adequate
combustion air for all appliances.
5. Local codes may require a back fl ow preventer or
actual disconnect from city water supply when
antifreeze is added to the system.
MINIMUM RECOMMENDED COMBUSTION
AIR SUPPLY TO EQUIPMENT ROOM
*Outside Air from
Model
Number
497
647
747
987
1257
1437
1797
2067
2 Openings Directly from
Outdoors
Top
Opening, in
125
(806 cm2)
163
(1052 cm2)
188
(1213 cm2)
248
(1600 cm2)
315
(2032 cm2)
360
(2323 cm2)
450
(2903 cm2)
518
(3342 cm2)
Bottom
2
Opening, in
(806 cm2)
(1052 cm2)
(1213 cm2)
(1600 cm2)
(2032 cm2)
(2323 cm2)
(2903 cm2)
(3342 cm2)
125
163
188
248
315
360
450
518
*Outside Air from
1 Opening Directly
from Outdoors, in
2
167
(1077 cm2)
217
(1400 cm2)
250
(1613 cm2)
330
(2129 cm2)
420
(2710 cm2)
480
(3097 cm2)
600
(3871 cm2)
690
(4452 cm2)
TABLE 1B
2 Ducts Delivered from
2
Top
Opening, in
250
(1613 cm2)
325
(2097 cm2)
375
(2420 cm2)
495
(3194 cm2)
630
(4065 cm2)
720
(4646 cm2)
900
(5807 cm2)
1035
(6678 cm2)
Inside Air from
Outdoors
Bottom
2
Opening, in
250
(1613 cm2)
325
(2097 cm2)
375
(2420 cm2)
495
(3194 cm2)
630
(4065 cm2)
720
(4646 cm2)
900
(5807 cm2)
1035
(6678 cm2)
Inside Air from
2 Ducts Delivered from Interior
Space
2
Opening, in
(3226 cm2)
(4194 cm2)
(4839 cm2)
(6388 cm2)
(8130 cm2)
(9291 cm2)
(11614 cm2)
(13356 cm2)
Top
500
650
750
990
1260
1440
1800
2070
2
Opening, in
(3226 cm2)
(4194 cm2)
(4839 cm2)
(6388 cm2)
(8130 cm2)
(9291 cm2)
(11614 cm2)
(13356 cm2)
Bottom
500
650
750
990
1260
1440
1800
2070
2
12
Page 13
Installation & Service Manual
1 Determine unit location (continued)
Figure 1-3_Combustion air filter_ Models 497 - 747
NOTICE
CAUTION
Combustion air filter
This unit has a standard air filter located at the combustion air inlet. This filter helps ensure clean air is used for the
combustion process. Check this filter every month and replace when it becomes dirty. The filter size on Models 497 - 747 is
12" x 12" x 1" (30.5cm x 30.5cm x 2.5cm) and 16" x 16" x 1" (40.6cm x 40.6cm x 2.5 cm) on Models 987 - 2067. You can find
these commercially available filters at any home center or HVAC supply store.
During construction the air filter should be checked more frequently to ensure it does not become clogged
with construction dirt and debris.
Sustained operation of an appliance with a clogged burner may result in nuisance operational problems,
bad combustion, and non-warrantable component failures.
Figure 1-4_Combustion air filter_ Models 987 - 2067
13
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1 Determine unit location
Installation & Service Manual
Combustion Air Options
CAUTION
This unit has four combustion air options.
1. Outside Combustion Air, No Ducts
You can direct outside combustion air to this unit using either
one or two permanent openings (see FIG. 1-5).
One Opening
The opening must have a minimum free area of one square
inch per 3000 Btu input (7 cm2 per kW). You must locate this
opening within 12'' (30 cm) of the top of the enclosure.
Figure 1-5_Outside combustion air single opening
Under no circumstances should a mechanical
room ever be under a negative pressure.
Particular care should be taken when exhaust
fans, clothes dryers, compressors, air handling
units, etc., take away air from the inlet.
Two Openings
The combustion air opening must have a minimum free area
of one square inch per 4000 Btu input (5.5cm² per kW). You
must locate this opening within 12'' (30cm) of the bottom of
the enclosure.
The ventilation air opening must have a minimum free area
of one square inch per 4000 Btu input (5.5cm² per kW). You
must locate this opening within 12'' (30cm) of the top of the
enclosure.
Figure 1-6_Outside combustion air, two openings
2. Outside Combustion Air, Using Ducts
You can direct outside combustion air to this unit using two air
ducts to deliver the air to the boiler room.
Each of the two openings must have a minimum free area of one
square inch per 2000 Btu input (11cm² per kW).
Figure 1-7_Outside combustion air, using ducts
14
Page 15
1 Determine unit location (continued)
Installation & Service Manual
3. Combustion Air from an Interior Space
You can direct combustion air to this unit using air from
an adjoining interior space. You must provide two openings
from the boiler room to the adjoining room. Each of the two
openings must have a net free area of one square inch per 1000
Btu input (22cm² per kW), but not less than 100 square inches
(645cm²).
Figure 1-8_Combustion air from an interior space
Exhaust Fans
WARNING
Any fan or equipment which exhausts
air from the boiler room may deplete the
combustion air supply and/or cause a
down draft in the venting system. Spillage
of flue products from the venting system
into an occupied living space can cause
a very hazardous condition that must be
corrected immediately. If a fan is used to
supply combustion air to the boiler room,
the installer must make sure that it does not
cause drafts which could lead to nuisance
operational problems with the boiler.
All dimensions are based on net free area in square inches.
Metal louvers or screens reduce the free area of a combustion air
opening a minimum of approximately 25%. Check with louver
manufacturers for exact net free area of louvers. Where two
openings are provided, one must be within 12'' (30 cm) of the
ceiling and one must be within 12'' (30 cm) of the floor of the
equipment room. Each opening must have a minimum net free
area as specified in TABLE 1B, page 12. Single openings shall be
installed within 12'' (30 cm) of the ceiling.
CAUTION
The combustion air supply must be
completely free of any flammable vapors
that may ignite or chemical fumes which
may be corrosive to the appliance. Common
corrosive chemical fumes which must be
avoided are fluorocarbons and other
halogenated compounds, most commonly
present as refrigerants or solvents, such as
Freon, trichlorethylene, perchlorethylene,
chlorine, etc. These chemicals, when
burned, form acids which quickly attack
the heat exchanger finned tubes, headers,
flue collectors, and the vent system. The
result is improper combustion and a nonwarrantable, premature unit failure.
15
Page 16
Installation & Service Manual
2 Venting
General information
You must supply adequate combustion and ventilation air to this unit. You must provide minimum clearances for the vent
terminal from adjacent buildings, windows that open, and building openings. Follow all requirements set forth in the latest edition
of the National Fuel Gas Code, ANSI Z223.1, in Canada, the latest edition of CAN/CGA Standard B149 Installation Code for Gas
Burning Appliances and Equipment or applicable local building codes. Vent installations for connection to gas vents or chimneys
must be in accordance with Part 7, “Venting of Equipment” of the above-mentioned standards.
NOTICE
DANGER
Examine the venting system at least once each year. Check all joints and vent pipe connections for tightness. Also
check for corrosion or deterioration. If you find any problems, correct them at once.
Failure to use correct venting materials can result in loss of life from flue gas spillage into working or living
space.
Venting support
Support horizontal portions of the venting system to prevent sagging. Provide an upward slope of at least 1/4 inch per foot
(21mm/m) on all horizontal runs from the unit to the vertical flue run or to the vent terminal on sidewall venting installations.
Do not use an existing chimney as a raceway if another appliance or fireplace is vented through the chimney. The weight of the
venting system must not rest on the unit. Provide adequate support of the venting system. Follow all local and applicable codes.
Secure and seal all vent connections. Follow the installation instructions from the vent material manufacturer.
Vertical vent termination clearances and location
The vent terminal should be vertical and exhaust outside the building at least 2 feet (0.61m) above the highest point of the roof
within a 10 foot (3.05m) radius of the termination.
The vertical termination must be a minimum of 3 feet (0.91m) above the point of exit.
A vertical termination less than 10 feet (3.05m) from a parapet wall must be a minimum of 2 feet (0.61m) higher than the parapet
wall.
You must locate the air inlet termination elbow at least 12'' (30cm) above the roof or above normal snow levels.
Keep the vent cap clear of snow, ice, leaves, and debris to avoid blocking the flue.
Figure 2-1_Vent termination from peaked roof - 10 ft. or
less from ridge
NOTICE
Vent terminations are not shown in FIG.’s 2-1 thru 2-4. Make sure all vertical vents are installed with vent
terminations recommended by the vent manufacturer.
16
Figure 2-2_Vent termination from peaked roof - 10 ft. or
more from ridge
Page 17
2 Venting (continued)
Installation & Service Manual
Figure 2-3_Vent termination from flat roof - 10 ft. or
less from parapet wall
CAUTION
Units which are shut down or will not operate may experience freezing due to convective air flow in flue
pipe, through the air inlet, or from negative pressure in the equipment room. In cold climates, operate pump
continuously to help prevent freezing of boiler water. Provide proper freeze protection. See Freeze Protection,
page 46.
TABLE 2A
FLUE PIPE SIZES
MODEL FLUE SIZE MODEL FLUE SIZE
497 6'' 1257 12''
647 8'' 1437 12''
747 8'' 1797 14''
987 10'' 2067 14''
Installer may increase diameter one pipe size for ease of installation, if needed.
Vent system options
Vent System Options
This unit has two venting options.
1. Conventional Negative Draft Venting
This option uses a vertical rooftop flue termination.
Combustion air is supplied from the mechanical room.
See page 15 for detailed information.
2. Outdoor Installation Venting
This option uses the installation of special air inlet and
vent caps on the unit.
All units are shipped from the factory equipped for
conventional negative draft venting. All other optional vent
systems require the installation of specific vent kits and venting
materials. The following is a detailed explanation of the
installation requirements for each venting system, components
used and part numbers of vent kits for each model.
Figure 2-4_Vent termination from flat roof - 10 ft. or more
from parapet wall
Barometric damper location
Any venting system option that requires a barometric
damper must adhere to the following directions for optimum
performance. The preferred location for the barometric damper
is in a tee or collar installed in the vertical pipe rising from the
unit’s flue outlet. The barometric damper MUST NOT be
installed in a bull head tee installed on the unit’s flue outlet.
The tee or collar containing the barometric damper should
be approximately three feet vertically above the connection to
the unit’s flue outlet. This location ensures that any positive
velocity pressure from the unit’s internal combustion fan is
dissipated and the flue products are rising due to buoyancy
generated from the temperature of the flue products. Adjust
the weights on the damper to ensure that draft is maintained
within the specified ranges.
17
Page 18
2 Venting
Installation & Service Manual
1. Conventional negative draft
venting
NOTICE
Figure 2-5_Conventional negative draft vertical venting
with combustion air louvers
This option uses Type-B double-wall flue outlet piping. The
blower brings in combustion air. The buoyancy of the heated
flue products causes them to rise up through the flue pipes. The
flue outlet terminates at the rooftop.
Before installing a venting system, follow
all venting clearances and requirements
found in the Venting, General Information
section, page 16.
Do not connect vent connectors serving appliances vented by
natural draft (negative draft) to any portion of a mechanical
draft system operating under positive pressure. Connecting to a
positive pressure stack may cause flue products to be discharged
into the living space causing serious health injury.
Flue outlet piping
The negative draft in a conventional vent installation must be
within the range of 0.02 to 0.08 inches w.c. to ensure proper
operation. Make all draft readings while the unit is in stable
operation (approximately 2 to 5 minutes).
Connect the flue vent directly to the flue outlet opening on
the top of the unit. No additional draft diverter or barometric
damper is needed on single unit installations with a dedicated
stack and a negative draft within the specified range of 0.02 to
0.08 inches w.c.
Common venting systems
You can combine the flue with the vent from any other negative
draft, Category I appliance. Using common venting for multiple
negative draft appliances requires you to install a barometric
damper with each unit. This will regulate draft within the
proper range. You must size the common vent and connectors
from multiple units per the venting tables for Type-B doublewall vents in the latest edition of the National Fuel Gas Code,
ANSI Z223.1 and/or CAN/CGA-B149 Installation Code.
Common venting systems may be too large when an existing
unit is removed.
Negative draft
The negative draft in a conventional vent installation must be
within the range of 0.02 to 0.08 inches w.c. to ensure proper
operation. Make all draft readings while the unit is in stable
operation (approximately 2 to 5 minutes).
Connect the flue vent directly to the flue outlet opening on
the top of the unit. No additional draft diverter or barometric
damper is needed on single unit installations with a dedicated
stack and a negative draft within the specified range of 0.02 to
0.08 inches w.c. If the draft in a dedicated stack for a single unit
installation exceeds the maximum specified draft, you must
install a barometric damper to control draft. Multiple unit
installations with combined venting or common venting with
other Category I negative draft appliances require each boiler
to have a barometric damper installed to regulate draft within
the proper range.
18
Page 19
2 Venting (continued)
Installation & Service Manual
Common venting systems may be too large when an existing
unit is removed.
At the time of removal of an existing appliance, the following
steps shall be followed with each appliance remaining connected
to the common venting system placed in operation, while other
appliances remaining connected to the common venting system
are not in operation.
1. Seal any unused opening in the common venting system.
2. Visually inspect the venting system for proper size and
horizontal pitch. Make sure there is no blockage or
restriction, leakage, corrosion and other unsafe conditions.
3. If possible, close all building doors and windows. Close all
doors between the space in which the appliances remaining
connected to the common venting system are located and
other building spaces.
4. Turn on clothes dryers and any other appliances 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.
5. Close fire place dampers.
6. Place in operation the unit being inspected. Follow the
lighting instructions. Adjust thermostat so unit will operate
continuously.
7. Test for spillage at the draft hood/relief opening after 5
minutes of main burner operation. Use the flame of a match
or candle, or smoke from a cigarette, cigar or pipe.
8. After making sure that each appliance remaining connected
to the common venting system properly vents when tested
as above, return doors, windows, exhaust fans, fireplace
dampers and other gas burning appliances to their previous
conditions of use.
9. Correct any improper operation of the common venting
system so that the installation conforms to the latest edition
of the National Fuel Gas Code, ANSI Z223.1, in Canada,
the latest edition of CAN/CGA-B149 Installation Code for
Gas Burning Appliances and Equipment. When resizing any
portion of the common venting system, resize to approach
the minimum size as determined using the appropriate
tables of the latest edition of the National Fuel Gas Code,
ANSI Z223.1, in Canada, the latest edition of CAN/
CGA-B149 Installation Code for Gas Burning Appliances
and Equipment.
Masonry chimney installation
A masonry chimney must be properly sized for the installation of
a high efficiency gas-fired appliance. Venting of a high efficiency
appliance into a cold or oversized masonry chimney can result
in operational and safety problems. Exterior masonry chimneys,
with one or more sides exposed to cold outdoor temperatures,
are more likely to have venting problems. The temperature of
the flue products from a high efficiency appliance may not be
able to sufficiently heat the masonry structure of the chimney
to generate proper draft. This will result in condensing of flue
products, damage to the masonry flue/tile, insufficient draft and
possible spillage of flue products into an occupied living space.
Carefully inspect all chimney systems before installation.
CAUTION
Inspection of a masonry chimney
A masonry chimney must be carefully inspected to determine
its suitability for the venting of flue products. A clay-tilelined chimney must be structurally sound, straight and free of
misaligned tile, gaps between liner sections, missing sections of
liner or any signs of condensate drainage at the breaching or
clean out. If there is any doubt about the condition of a masonry
chimney, it must be relined with a properly-sized and approved
chimney liner system.
Vertical vent termination clearances and
location
Follow all vertical venting termination information for
clearances and location under Vertical Vent Termination
Clearances and Location, page 16.
Venting of high efficiency appliances into a
masonry chimney without a sealed stainless
steel liner can result in operational and safety
problems. Any breaks, leaks, or damage to
the masonry flue/tile will allow spillage of
the positive pressure flue products from the
chimney. These flue products can easily
escape into an occupied living space causing
a health hazard. If there is any doubt about
the condition of a masonry chimney, or
its acceptability for use after insertion of
a corrosion resistant liner system, consult
with local code officials.
19
Page 20
2 Venting
2. Outdoor installation venting
Installation & Service Manual
NOTICE
WARNING
Units are self-venting and can be used outdoors when installed
with the optional outdoor caps. These caps mount directly
to the unit and cover the flue outlet and combustion air inlet
openings. No additional vent piping is required.
Combustion air supply must be free of contaminants (see
Combustion and Ventilation Air, page 12). To prevent
recirculation of the flue products into the combustion air inlet,
follow all instructions in this section.
Before installing a venting system, follow
all venting clearances and requirements
found in the Venting, General Information
section, page 16.
Only install outdoor models outdoors
and only use the vent caps supplied by
the appliance manufacturer. Personal
injury or product damage may result if
any other cap is used or if an outdoor
model is used indoors. Properly install all
covers, doors and jacket panels to ensure
proper operation and prevent a hazardous
condition.
Outdoor vent/air inlet location
Keep venting areas free of obstructions. Keep area clean and
free of combustible and flammable materials. Maintain a
minimum clearance of 3'' (76mm) to combustible surfaces and
36" clearance to the rear of the unit for outdoor installations.
To avoid a blocked air inlet or blocked flue condition, keep
the air inlet, flue outlet and drain slot clear of snow, ice, leaves,
debris, etc.
NOTICE
CAUTION
CAUTION
Multiple outdoor unit installations require
48'' (1.22m) clearance between each vent
cap. Locate the outdoor cap at least 48''
(1.22m) below and 48'' (1.22m) horizontally
from any window, door, walkway or gravity
air intake.
Locate the unit at least 10 feet (3.05m) away
from any forced air inlet.
Locate the unit at least 3 feet (0.91m)
outside any overhang.
Clearances around outdoor installations can
change with time. Do not allow the growth
of trees, shrubs or other plants to obstruct
the proper operation of the outdoor vent
system.
A minimum of 3 feet must be maintained
at all times from outdoor air vent cap
surfaces to combustible construction and/or
materials.
Do not install in locations where rain from
building runoff drains will spill onto the
unit.
CAUTION
CAUTION
20
Do not install outdoor models directly on
the ground. You must install the outdoor
unit on a concrete, brick, block, or other
non-combustible pad.
Do not locate unit so that high winds
can deflect off of adjacent walls, buildings
or shrubbery causing recirculation.
Recirculation of flue products may cause
operational problems, bad combustion or
damage to controls. Locate unit at least
3 feet (0.91m) from any wall or vertical
surface to prevent wind conditions from
affecting performance.
Page 21
2 Venting (continued)
Installation & Service Manual
3'
3'
3'
3'
3'
3'
Figure 2-6_Outdoor vent cap installed on Models
497 - 747
3'
3'
Figure 2-7_Outdoor vent cap installed on Models
987 - 2067
Outdoor vent kit
The optional outdoor vent kit is available from the appliance manufacturer. The outdoor kit part numbers are listed by unit size.
See Table 2B for kit numbers.
You can install the outdoor vent cap and combustion air inlet panel(s) on the unit (see FIG.’s 2-6 and 2-7).
TABLE 2B
Outdoor Vent Kits
Model
497 ODK3023 ODK3014
647 ODK3024 ODK3015
747 ODK3024 ODK3015
987 ODK3049 ODK3036
1257 ODK3065 ODK3064
1437 ODK3050 ODK3037
1797 ODK30001 ODK30002
2067 ODK30001 ODK30002
* These kits include an outdoor vent cap, air inlet hood(s), and gasket.
Kit*
w/ Pump Cover
Kit*
without Pump Cover
21
Page 22
3 Gas connections
CAP
NIPPLE
MANUNUAL MAIN
SHUT OFF
VALVE
UNION
COUPLING
8"
MIN
USE WRENCNCH
TO HOLD
SUPPLY PIPE
Installation & Service Manual
Connecting to gas supply
Verify that the appliance is supplied with the type of gas specified
on the rating plate. This appliance is configured for operation
up to 2000 feet altitude. Consult factory for installations above
2000 feet elevation.
Inlet gas pressure: Measured at the inlet pressure tap on the
appliance gas manifold. The pressure tap is located upstream of
the combination gas valve(s).
See Table 3A for maximum and minimum inlet pressures. Do
not exceed the maximum. Minimum inlet pressure is for the
purpose of input adjustment.
TABLE 3A
INLET GAS PRESSURE
NATURAL LP
MODEL
497 - 747 14'' 4.0'' 14.0'' 8.0''
987 - 2067 14'' 4.5'' 14.0'' 8.0''
Manifold pressure: The gas regulator on the unit’s
combination gas valve is adjustable to supply proper manifold
pressure for normal operation.
Max.
w.c.
Min.
w.c.
Max.
w.c.
Min.
w.c.
Gas piping
To safely operate this unit, you must properly size the gas
supply piping. See Tables 3B through 3D for piping and
fitting requirements. Gas pipe size may be larger than heater
connection.
The gas connection for Models 497 - 747 is 1 1/4'' NPT and on
Models 987 - 2067 the gas connection to these units is 2'' NPT.
For ease of service, install a union.
Install a manual main gas shutoff valve, outside of the unit gas
connection within six feet of the unit in accordance with the
requirements of the National Fuel Gas Code, ANSI Z223.1.
You must provide a sediment trap (drip leg) in the inlet of the
gas connection to the unit.
NOTICE
The combination gas valves have an integral vent limiting
device and do not require venting to atmosphere, outside the
building. The unit will not operate properly if the reference hose
is removed or a vent to atmosphere is installed.
Optional gas controls may require routing of bleeds and vents
to the atmosphere, outside the building when required by local
codes.
It is the installer’s responsibility to supply
the sediment trap (drip leg).
NOTICE
If an inline high gas pressure regulator is
used, it MUST BE of the lockup type and
be located a minimum of 10 feet from the
appliance. Failure to do so may result in
insufficient gas volume supplied to the
appliance.
If you must adjust regulator pressure, follow the instructions
under Gas Manifold Pressure Adjustment on page 25. Do not
increase regulator pressure beyond specified pressure setting.
Gas pressure test
1. The appliance must be disconnected from the gas
supply piping system during any pressure testing of that
system at a test pressure in excess of 1/2 PSIG (3.5 kPa).
2. The appliance must be isolated from the gas supply
piping system by closing a manual shutoff valve during
any pressure testing of the gas supply piping system at
test pressures equal to or less than 1/2 PSIG (3.5 kPa).
3. The appliance and its gas connection must be leak
tested before placing it in operation.
Figure 3-1_Gas line connection
8"
UN
VA
22
Page 23
3 Gas connections (continued)
Installation & Service Manual
Gas connection
All gas connections must be made with pipe joint compound
resistant to the action of liquefied petroleum (L.P.) and natural
gases. All piping must comply with local codes and ordinances.
Piping installations must comply with approved standards and
practices.
1. Make sure gas line is a separate line direct from the meter
unless the existing gas line is of sufficient capacity. Verify
pipe size with your gas supplier.
2. Use new, properly threaded black iron pipe free from
chips. If you use tubing, make sure the ends are cut
square, deburred and clean. Make all tubing bends smooth
and without deformation. Avoid flexible gas connections.
Internal diameter of flexible lines may not provide unit with
proper volume of gas.
3. Install a manual main gas shutoff valve at the unit’s gas inlet,
outside of the unit.
4. Run pipe or tubing to the unit’s gas inlet. If you use tubing,
obtain a tube to pipe coupling to connect the tubing to the
unit’s gas inlet.
5. Install a sediment trap in the supply line to the unit’s gas
inlet (see FIG. 3-1).
6. Apply a moderate amount of good quality pipe compound
(do not use Teflon tape) to pipe only, leaving two end
threads bare.
7. Remove seal over gas inlet to unit.
8. Connect gas pipe to inlet of unit. Use wrench to support gas
manifold on the unit.
9. For L.P. gas, consult your L.P. gas supplier for expert
installation.
10. Ensure that all air is completely bled from the gas line before
starting the ignition sequence. Start up without properly
bleeding air from the gas line may require multiple reset
functions of the ignition control module to achieve proper
ignition.
WARNING
Gas train and controls
NOTICE
Do not have any open flame in proximity to
the gas line when bleeding air from the gas
line. Gas may be present.
The gas train and controls assembly
provided on this unit have been tested under
the applicable American National Standard
to meet minimum safety and performance
criteria such as safe lighting, combustion
and safety shutdown operation.
TABLE 3B
SUGGESTED GAS PIPE SIZE FOR
SINGLE UNIT INSTALLATIONS
MODEL
Distance from Meter (in feet)
0 - 50 51 - 100 101 - 200 201 - 300 301 - 500
497 1 1/4'' 1 1/4'' 1 1/2'' 2'' 2''
647 1 1/4'' 1 1/2'' 2'' 2'' 2 1/2''
747 1 1/2'' 2'' 2'' 2 1/2'' 2 1/2''
987 2'' 2'' 2 1/2'' 2 1/2'' 3''
1257 2'' 2 1/2'' 2 1/2'' 3'' 3''
1437 2 1/2'' 2 1/2'' 3'' 3'' 3 1/2''
1797 2 1/2'' 3'' 3'' 3 1/2'' 3 1/2''
2067 2 1/2'' 3'' 3'' 3 1/2'' 4''
For each elbow or tee, add equivalent straight pipe to total length from Table 3C.
TABLE 3C
FITTINGS TO EQUIVALENT STRAIGHT PIPE
Diameter
Pipe
(inches)
Equivalent
length of
Straight Pipe
(feet)
Water heater models do not have downstream test valves, but
the rest of the gas train is represented by FIG. 3-2.
Figure 3-2_Gas train drawing
COMBINATION
VALVE
DOWNSTREAM
TEST VALVE
3/4 1 1 1/4 1 1/2 2 3 4 5
223 45101420
497 MODEL
TO BURNERS
DOWNSTREAM
TEST VALVE
COMBINATION
VALVE
2067 MODEL
TO BURNERS
23
Page 24
3 Gas connections
Installation & Service Manual
Combination gas valves
These units fire in multiple stages of burner input. Each stage
of burner operation has a combination gas valve(s) to cycle
the gas supply on and off and regulate gas to the burners. Each
combination valve consists of a gas regulator and two valve seats
to meet the requirements for redundant gas valves. The valve
has a gas control knob that must remain in the open position
at all times when the unit is in service. The gas control valve
has pressure taps located on the inlet and discharge sides of the
valve. Manifold pressure is adjusted using the regulator located
on the valve. A manifold gas pressure tap for each burner stick
is located on the discharge side of the valve. The manifold
pressure is preset at the factory and adjustment is not usually
required. If you must adjust regulator pressure, follow the
instructions under Gas Manifold Pressure Adjustment, page 25.
Venting of combination gas valves
The combination gas valve/regulator used on all units is
equipped with an integral vent limiting orifice per ANSI Z21.78.
The vent limiter ensures that the volume of gas emitted from
the valve in the event of a failed gas diaphragm does not exceed
the maximum safe leakage rate allowed by agency requirements.
Combination gas valve/regulators equipped with integral vent
limiters are not required to have vent or relief lines piped to
the outdoors. The termination of the vent limited opening on
the combination gas valve/regulator complies with the safety
code requirements of CSD-1, CF-190(a) as shipped from the
appliance manufacturer without the installation of additional
vent lines.
Checking gas supply pressure
Use the following procedure to check gas supply pressure.
1. Turn the main power switch to the “OFF” position.
2. Turn gas valve knobs to the “OFF” position.
3. Shut off gas supply at the field-installed manual gas cock in
the gas piping to the unit. If fuel supply is L.P. gas, shut off
gas supply at the tank.
4. Remove the 1/8'' hex plug, located on the “inlet” side of the
gas valve (FIG. 3-3). You may also use a tapping on the
field-installed main manual gas cock or gas piping. Install a
fitting in the inlet pressure tapping suitable to connect to a
manometer or magnehelic gauge. Range of scale should be
14'' w.c. or greater to check inlet pressure.
5. Turn on gas supply at the manual gas cock, turn on L.P. gas
at the tank if required.
6. Turn the power switch to the “ON” position.
7. Turn the gas valve knobs to the “ON” position. Set the
electronic temperature control or thermostat to call for
heat.
8. Observe the gas supply pressure as all burners are firing.
Ensure that inlet pressure is within the specified range.
See Connecting To Gas Supply, page 22 for minimum and
maximum gas supply pressures.
9. If gas pressure is out of range, contact gas utility, gas
supplier, qualified installer or service agency to determine
necessary steps to provide proper gas pressure to the
control.
TABLE 3D
GAS PIPING SIZE CHART
Nominal
Iron Pipe
Size
Inches
3/4 369 256 205 174 155 141 128 121 113 106 95 86 79 74
1 697 477 384 328 292 267 246 256 210 200 179 164 149 138
1 1/4 1,400 974 789 677 595 543 502 472 441 410 369 333 308 287
1 1/2 2,150 1,500 1,210 1,020 923 830 769 707 666 636 564 513 472 441
2 4,100 2,820 2,260 1,950 1,720 1,560 1,440 1,330 1,250 1,180 1,100 974 871 820
2 1/2 6,460 4,460 3,610 3,100 2,720 2,460 2,310 2,100 2,000 1,900 1,700 1,540 1,400 1,300
3 11,200 7,900 6,400 5,400 4,870 4,410 4,000 3,800 3,540 3,300 3,000 2,720 2,500 2,340
4 23,500 16,100 13,100 11,100 10,000 9,000 8,300 7,690 7,380 6,870 6,150 5,640 5,130 4,720
10 20 30 40 50 60 70 80 90 100 125 150 175 200
Length of Pipe in Straight Feet
24
Maximum
Capacity of Pipe
in Thousands of
Btu/hr per hour
for gas pressures
of 14 Inches
Water Column
(0.5 PSIG) or less
and a pressure
drop of 0.5 Inch
Water Column
(Based on NAT
GAS, 1025 Btu/hr
per Cubic Foot
of Gas and 0.60
Specific Gravity)
Page 25
3 Gas connections (continued)
GAS
VALVE
CONTROL
KNOB
OUTLET
Installation & Service Manual
10. If gas supply pressure is within normal range, remove the
gas manometer and replace the pressure tap fittings in the
gas control as indicated by the following steps.
11. Turn power switch to the “OFF” position.
12. Turn gas valve knob to the “OFF” position.
13. Shut off gas supply at the manual gas cock in the gas piping
to the unit. If fuel supply is L.P. gas, shut off gas supply at
the tank.
14. Remove the manometer and related fittings from the “inlet
side of the gas valve, replace 1/8'' hex plug in the gas valve
and tighten.
15. Turn on the gas supply at the manual valve, turn on L.P. gas
at the tank if required.
16. Turn the power switch to the “ON” position.
17. Turn the gas valve knob to the “ON” position.
18. Set the electronic temperature control or thermostat to call
for heat.
WARNING
After completing any testing on the gas
system, leak test all gas connections. Apply
a soap/water solution to all gas connections
while main burners are operating. Bubbles
forming indicate a leak. Repair all leaks at
once. Do not operate this unit with a leak in
the gas train, valves or related piping.
Check burner performance by cycling the system while you
observe burner response. Burners should ignite promptly.
Flame pattern should be stable, see Burner Flames in the
Maintenance section of this manual. Turn system off and allow
burners to cool, then cycle burners again to ensure proper
ignition and flame characteristics.
Gas manifold pressure adjustment
NOTICE
1. Remove the thumbscrew that fastens the control panel
access door and remove the door.
2. Turn the power switch located in the lower left corner
behind the control panel access door to the “O” or “OFF”
position.
3. Remove the top front jacket access panels to access the gas
valve(s).
4. Locate the reference hose on the first gas valve which goes
from the vent fitting on the gas valve to the barbed fitting
on the deck of the unit (see FIG. 3-4).
5. Remove the flexible cap from the barbed fitting on the “tee”
located in this line and hook one side of the manometer, or
(-) side of a magnahelic gauge, to this “tee”. Retain this cap
for future use.
The gas valves are referenced to the fan
pressurized chamber by a hose connected
from the vent of the gas valve regulator
to the chamber pressure tap located on
the front inside portion of the jacket.
Reference the drawings in this section for
component and connection points for
pressure measurement. The referenced
chamber pressure must be subtracted from
the manifold pressure to obtain actual net
manifold pressure for normal operation.
A manometer or magnahelic gauge legible
in 0.1'' increments up to 10 inches w.c. is
required to check and adjust the manifold
pressure. The regulator cover screw on the
gas valve must be in place and tight for the
unit to operate properly.
Figure 3-3_Measuring gas supply pressure at combination
gas valve
SUPPLY INLET
PRESSURE TAP
INLET
6. Remove the 1/8'' hex plug from the manifold pressure tap
on the gas valve (see FIG. 3-4). Retain plug for future use.
7. Install a fitting in this tap that is suitable for connection of
a hose to a manometer, or (+) side of a magnahelic gauge
(see FIG. 3-4).
8. Turn the power switch to the “I” or “ON” position.
9. Push the reset button(s) for the ignition control(s), if
necessary.
10. Set the temperature control to call for heat (see Setting
Temperature Control, page 39).
11. Once the unit is firing, the manometer/magnahelic will
reflect the net manifold gas pressure. Compare this reading
to the respective value in Table 3E for Natural Gas or
Propane Gas.
25
Page 26
3 Gas connections
Installation & Service Manual
12. If adjustment is necessary, remove the regulator
cover screw on the gas valve. Note: If the gas valve
under adjustment is located on a manifold assembly
monitored by an igniter, the unit may shut down and
recycle when the regulator cover screw is removed.
This is normal.
13. Turn the regulator adjustment screw “clockwise” to
raise the regulator gas pressure. Turn the regulator
adjustment screw “counterclockwise” to lower the
regulator gas pressure.
14. Replace the regulator cover screw and make sure it is
tight for proper operation.
Figure 3-4_Measuring manifold gas pressure
PRESSURE
REGULATOR
MANIFOLD
PRESSURE
ADJUSTMENT
(UNDER CAP
SCREW)
INLET
15. Read the value on the manometer/magnahelic and
compare it to the values in TABLE- 3E.
16. Repeat this adjustment procedure for each gas valve as
necessary to adjust to the proper manifold gas pressure.
17. Remove hoses, replace and tighten plugs and caps
when complete.
18. Replace top front upper jacket access panels and
control panel door in reverse order.
19. If proper ignition and burner operation is not
achieved after checking gas supply pressure, see
Cleaning and Maintenance, page 58 for Combustion
Air Fan Adjustment. Follow the procedure to adjust
the combustion air fans as necessary.
CHAMBER
PRESSURE
TEE
MANOMETER
497 - 747 1.8'' w.c. --
987 - 2067 1.2'' w.c. --
26
OUTLET
GAS
VALVE
CONTROL
KNOB
TO BARBED
FITTING
TABLE 3E
Net Manifold Pressure
Regulator Pressure Less
Front Chamber Pressure
MODEL Nat. Gas LP
497-2067 -- 4.6'' w.c.
Page 27
4 Water connections
Installation & Service Manual
Inlet and outlet connections
For ease of service, install unions on the water inlet and water
outlet of the unit. The connection to the unit marked “Inlet”
on the header should be used for return from the system. The
connection on the header marked “Outlet” is to be connected to
the supply side of the system.
Figure 4-1_Water Connections_Models 497 - 797
2" NPT
WATER
INLET
2" NPT
WATER
OUTLET
NEED NEW IMAGE
INSPECTION
PLUGS
Figure 4-2_Water Connections_Models 987 - 2067
2-1/2" NPT
WATER
INLET
2-1/2" NPT
WATER
OUTLET
Water flow switch
A water flow switch is factory installed in the outlet piping on
all heating boilers and water heaters. The flow switch must
prove water flow before a trial for ignition can begin. The flow
switch requires a minimum flow of 15 - 18 GPM on Models
497 - 747 and 26 GPM on Models 987 - 2067 to make the flow
switch and start burner operation. A water flow switch meets
most code requirements for a low water cutoff device on boilers
requiring forced circulation for operation.
Low water cutoff (if equipped)
If this boiler is installed above radiation level, a low water cutoff
device must be installed at the time of boiler installation. An
electronic low water cutoff is available as a factory supplied
option on all models. The low water cutoff should be inspected
every 6 months.
Heating boiler installations
Piping of the boiler system
The drawings in this section show typical boiler piping
installations, see FIG.’s 4-5 through 4-8. Before beginning
the installation, consult local codes for specific plumbing
requirements. The installation should provide unions and
valves at the inlet and outlet of the boiler so it can be isolated
for service. An air separation device must be supplied in the
installation piping to eliminate trapped air in the system.
Locate a system air vent at the highest point in the system. The
system must also have a properly sized expansion tank installed.
Typically, an air charged diaphragm-type expansion tank is
used. The expansion tank must be installed close to the boiler
and on the suction side of the system pump to ensure proper
operation.
INSPECTION
PLUGS
Relief valve
This unit is supplied with a relief valve(s) sized in accordance
with ASME Boiler and Pressure Vessel Code, Section IV
(“Heating Boilers”). The relief valve(s) is installed in the vertical
position and mounted in the hot water outlet. No valve is to be
placed between the relief valve and the unit. To prevent water
damage, the discharge from the relief valve shall be piped to a
suitable floor drain for disposal when relief occurs. No reducing
couplings or other restrictions shall be installed in the discharge
line. The discharge line shall allow complete drainage of the
valve and line. Relief valves should be manually operated at
least once a year.
CAUTION
Avoid contact with hot discharge water.
CAUTION
The boiler system should not be operated at
less than 12 PSIG.
Hot water piping must be supported by suitable hangers or floor
stands, NOT by the boiler. Copper pipe systems will be subject
to considerable expansion and contraction. Rigid pipe hangers
could allow the pipe to slide in the hanger resulting in noise
transmitted into the system. Padding is recommended on rigid
hangers installed with a copper system. The boiler pressure
relief valve must be piped to a suitable floor drain. See the Relief
Valve section on this page.
CAUTION
A leak in a boiler “system” will cause the
“system” to intake fresh water constantly,
which will cause the tubes to accumulate a
lime/scale build up. This will cause a nonwarrantable failure.
27
Page 28
4 Water connections
Installation & Service Manual
Water connections (heating boilers only)
Inlet and outlet water connections on Models 497 - 747
have 2'' NPT and on Models 987 - 2067 the inlet and outlet
connections are 2 1/2'' NPT.
CAUTION
Field installed reducing bushings must not
be used to reduce below the pipe diameters
of the models listed above.
Any reduction in pipe size may decrease flow resulting in high
water temperatures, boiler noise, flashing to steam, and nonwarrantable heat exchanger damage.
The boiler may be installed with a primary/secondary piping
system provided to the boiler. It is important to guarantee that
adequate flow is provided to properly dissipate heat from the
boiler and also ensure that flow through the boiler does not
exceed the maximum recommended flow rate of 55 GPM for
Models 497 - 747 and 90 GPM for Models 987 - 2067 for a boiler
equipped with a copper heat exchanger.
Boiler circulator requirements
This is a low mass, high efficiency hot water boiler which
must have adequate flow for quiet, efficient operation. Pump
selection is critical to achieve proper operation. A pump should
be selected to achieve proper system design water temperature
rise. Pipe diameter and length are critical to ensure proper flow
through the boiler. A System Temperature Rise Chart (Table 4B
on page 30) is provided to assist in proper pump selection. This
table provides GPM and boiler head-loss at various temperature
rises for each model based on Btu/hr input. Temperature rise
is the difference in boiler inlet temperature and boiler outlet
temperature while the boiler is firing at full rate.
Circulator pump specifications
1. Maximum operating pressure for the pump must exceed
system operating pressure.
2. Maximum water temperature should not exceed the
nameplate rating.
3. Cast iron circulators may be used for closed loop systems.
4. A properly sized expansion tank must be installed near the
boiler and on the suction side of the pump.
Circulator pump operation (heating boilers only)
The boiler pump must run when the boiler is firing. Separate
supply circuits can be provided or the two circuits (pump
and controls) can be combined for connection to one circuit,
properly sized for both.
Pump delay operation
A pump delay operation feature is provided. The boiler’s
circulating pump will cycle on at each call for heat, before the
burner fires. The pump will continue to operate while the
burner is firing. The pump will run for a minimum 30 second
period after the temperature set point is satisfied. This timing
will remove any of the residual heat from the combustion
chamber before turning the pump off. See the wiring diagram
in Section 10 of this manual.
Example: The boiler inlet temperature is 160°F (71.1°C) and
the boiler outlet temperature is 180°F (82.2°C). This means that
there is a 20°F (11.1°C) temperature rise across the boiler. The
boiler temperature rise is visible in the Operator Interface on the
boiler’s front control panel.
Figure 4-3_Heat exchanger pressure drop chart_
Models 497- 747
Pressure Drop Chart
Models 497 - 747
12
10
8
6
4
2
0
80
75
70
65
60
55
50
45
40
30
20
10
PRESSURE DROP IN FEET HEAD
FLOW IN GALLONS PER MINUTE
Figure 4-4_Heat exchanger pressure drop chart_
Models 987 - 2067
MODELS 987 - 2067
28
Page 29
4 Water connections (continued)
Installation & Service Manual
Pump Maintenance: Inspect the pump every six (6) months
and oil as necessary. Use SAE 30 non-detergent oil or lubricant
specified by the pump manufacturer.
The boiler is recommended for installation in a primary/
secondary piping system. This type of system uses a separate
boiler circulating pump to supply flow to and from the boiler
only. The secondary pump is sized based on the head loss of the
boiler and related pipe and fittings in the secondary loop only.
A properly sized primary system pump provides adequate
flow to carry the heated boiler water to radiation, air over
coils, etc. The fittings that connect the boiler to the primary
system should be installed a maximum of 12 inches (0.30m)
(or 4 pipe diameters) apart to ensure connection at a point of
zero pressure drop in the primary system. There should be a
minimum of 10 pipe diameters of straight pipe before and after
the boiler secondary loop connections to prevent turbulent
flow at the secondary loop connections. The secondary loop
piping to and from the boiler must have a fully ported ball valve
installed in both the supply and return side piping. The ball
valves must be fully ported having the same inside diameter as
the installed piping. The ball valve in the piping supplying water
to the boiler will only be used as a service valve. The ball valve
installed in the discharge from the boiler back to the primary
system will be used to adjust boiler flow and temperature rise to
ensure proper performance.
The boiler primary piping system must have a circulator
installed in the main system loop to carry the heated boiler
water to the point of use in the main system.
Minimum boiler water temperatures
Inlet water temperatures below the specified minimum of
140°F (60°C) can excessively cool the products of combustion
resulting in condensation on the heat exchanger. Condensation
on the heat exchanger can cause operational problems, bad
combustion, sooting, flue gas spillage and reduced service life
of the related components. See the Low Temperature Bypass
Requirements section for boiler system applications below the
minimum specified temperature.
Low system water volume
System run time is very important to the overall operating
efficiency of the boiler. Short cycling of the boiler creates
problems with condensation in the vent stack, condensation on
the heat exchanger, system temperature spikes, and mechanical
component failures. To prevent short cycling of the boiler, it
is important to limit the boiler cycles to six or fewer per hour.
A buffer tank is an effective way to enhance a small system load
and increase heating system efficiency (see FIG. 4-8 on page 34
of this manual). Buffer tanks add water volume to the system
and act as a flywheel to absorb the additional Btu’s provided by
the boiler when only a single zone of a large system is calling
for heat.
To calculate the proper buffer tank size for a multiple zone
system:
(Run Cycle) (Output - Minimum System Load)
(Temp. Rise) (8.33) (60 Min.)
Multiple boilers may also be installed with a primary/secondary
manifold system. Multiple boilers should be connected to the
common manifold in reverse return to assist in balancing flow
to multiple boilers.
The installer must ensure that the boiler has adequate flow
without excessive temperature rise. Low system flow can result
in overheating of the boiler water which can cause short burner
cycles, system noise, relief valve discharge and in extreme cases,
a knocking flash to steam. These conditions indicate the need
to increase boiler flow to and from the boiler. This is generally
accomplished by either increasing the size of the boiler pump or
by increasing the diameter of the piping that connects the boiler
to the primary system. A larger diameter pipe reduces head loss
and increases flow.
CAUTION
CAUTION
At no time should the system pressure be less
than 12 PSIG.
Do not allow the flow in the primary loop
to drop lower than the flow in the secondary
loop at any time during boiler operation.
Improper operation of the boiler(s) and
possible tripping of the high limits and relief
valves may occur.
CFN2067
Min. Load = 100,000 Btu/Hr
Min. Boiler Output = 850,000 Btu/Hr
Cycle Time = 10 Min
Temp. Rise = 38
(10)(850,000 – 100,000) / (38)(8.33)(60) = 395 Gallons
29
Page 30
4 Water connections
Installation & Service Manual
Low temperature return water systems
Any non-condensing boiler and venting system will develop
operational problems when exposed to inlet water temperatures
below 140°F. Lochinvar offers a low temperature protection
valve (LTV) that is factory preset to maintain 140°F inlet water
to the boiler regardless of the system return water temperature.
See Table 4A for available valve kits.
TABLE 4A
LTV VALVE KITS
MODEL LTV VALVE KIT
497 - 747 VAL3048
987 - 2067 VAL3047
Be sure to install the LTV valve per the piping diagrams included
with the kits. Alternatively, a bypass as shown in FIG. 4-6 may
be piped into the system. This piping is like a primary/secondary
boiler installation with a bypass in the secondary boiler piping.
Inlet water temperatures below 140°F (60°C) can excessively
cool the products of combustion resulting in condensation on
the heat exchanger and in the flue.
Condensation can cause operational problems, bad combustion,
sooting, flue gas spillage and reduced service life of the vent
system and related components. The bypass allows part of the
boiler discharge water to be mixed with the cooler boiler return
water to increase the boiler inlet temperature above 140°F
(60°C). This should prevent the products of combustion from
condensing in most installations. The bypass should be fully sized
with a balancing valve to allow for proper adjustment. A valve
must also be provided on the boiler discharge, after the bypass.
Closing this discharge valve forces water through the bypass.
Start boiler adjustment with the bypass valve in the full open
position and the boiler discharge valve half open. A small
amount of the higher temperature boiler discharge water is
mixed with the system water to maintain the desired lower
system temperature. A remote low temperature range operator
is recommended to control the boiler operation based on the
lower system temperature. (See Terminal Strip Connection
Options starting on page 38).
Radiant floor and snow melt heating
systems
This type of heating boiler application operates in a low
temperature range which requires a boiler bypass as described
under the Low Temperature Bypass Requirements section. A
non-metallic rubber or plastic tubing installed in a radiant (in
floor) system must have an oxygen barrier to prevent oxygen
from entering the system through the walls of the installed
tubing. Excessive oxygen absorption into the system will result
in an accelerated rate of corrosion causing a sludge buildup.
This excessive corrosion will also damage the boiler and system
components. Sludge formed as the result of excessive oxygen
in the system can restrict water flow resulting in a premature
boiler failure. Any boiler damage due to excessive oxygenation
is non-warrantable.
TABLE 4B
SYSTEM TEMPERATURE RISE CHART
Temperature Rise Based on Boiler Input in Btu/hr
Btu/hr 10°F T 20°F T 30°F T 40°F T 50°F T 60°F T
Input Output GPM Ft/hd GPM Ft/hd GPM Ft/hd GPM Ft/hd GPM Ft/hd GPM Ft/hd
497,000 400,950 80+ * 40 4.0 27 1.6 20 0.6 16 0.6 13 0.6
647,000 522,450 129+ * 52 5.1 35 3.0 26 1.2 21 0.8 17 0.6
747,000 603,450 149+ * 60 * 40 4.0 30 1.6 24 1.2 20 0.7
987,000 831,600 197+ * 80 5.2 53 2.4 40 1.4 32 1.0 27 0.8
1,257,000 1,058,000 251+ * 102+ * 68 4.3 51 2.3 41 1.6 34 1.1
1,437,000 1,209,000 288+ * 116+ * 78 6.0 58 3.7 47 2.2 39 1.7
1,797,000 1,512,000 360+ * 146+ * 97+ * 73 6.2 58 4.2 49 2.4
2,067,000 1,738,800 414+ * 168+ * 112+ * 84 8.7 67 6.0 56 4.5
+ These flow rates exceed recommended flow rates of boiler. If these system temperature rises are used, an external piping bypass must be
installed.
*These foot head calculations exceed the maximum allowable flow rate of the boiler. Requires Cupro-Nickel heat exchanger.
30
Page 31
4 Water connections (continued)
Figure 4-5_Primary/secondary piping of single boiler
Installation & Service Manual
COMMON MANIFOLD SIZE (Min.)
Models: 497 - 747
Number of Units GPM
Diameter
(in.)
1 60 2 1/2
COMMON MANIFOLD SIZE (Min.)
Models: 987 - 2067
Number of Units GPM
Diameter
(in.)
1 90 2 1/2
TO EXPANSION
TANK AND MAKEUP
WATER SYSTEM
HEATING
RETURN
LOOP
HEATING
SUPPLY
LOOP
NOTICE
TO
FLOOR
DRAIN
12"
MAX
*Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
31
Page 32
4 Water connections
Figure 4-6_Primary/secondary piping of multiple boilers
Installation & Service Manual
COMMON MANIFOLD SIZE (Min.)
Models: 497 - 747
Number of Units GPM
Diameter
2 120 3 1/2
3 180 4
4 240 5
5 300 5
6 360 6
7 420 6
8 480 6
PRESSURE
RELIEF
VALVE
MAKE-UP
WATER
(in.)
COMMON MANIFOLD SIZE (Min.)
Number of Units GPM
EXPANSION
TANK
LOW WATER
CUT-OFF
(OPTIONAL)
Models: 987 - 2067
Diameter
(in.)
2 180 4
3 270 5
4 360 6
5 450 6
6 540 6
7 630 8
8 720 8
TO SYSTEM
NOTICE
AIR
SEPARATOR
12" OR 4X
PIPE DIAMETERS
FROM
SYSTEM
SECONDARY
BOILER
PUMP
SYSTEM
PUMP
*Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
32
Page 33
HEAEATITING
SUPP
LY
LOOP
TO
FLOOR
DRAIN
MIXING
VALVE
TO EXPANSION
TANK A
ND M
AKEUP
WATER SYSTEM
HEATITING
RET
URN
L
OOP
12”
MAX
4 Water connections (continued)
Figure 4-7_Boiler with low temperature bypass
Installation & Service Manual
COMMON MANIFOLD SIZE (Min.)
Models: 497 - 747
Number of Units GPM
Diameter
(in.)
1 60 2 1/2
ND
COMMON MANIFOLD SIZE (Min.)
Models: 987 - 2067
Number of Units GPM
1 90 2 1/2
AKE
Diameter
(in.)
UR
OO
NOTICE
DR
LY
12”
*Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
33
Page 34
4 Water connections
Figure 4-8_Primary/secondary piping with buffer tank
Installation & Service Manual
COMMON MANIFOLD SIZE (Min.)
Models: 497 - 747
Number of Units GPM
Diameter
2 120 3 1/2
3 180 4
4 240 5
5 300 5
6 360 6
7 420 6
8 480 6
1" TEMPERATURE
AND PRESSURE
GAUGE
(in.)
COMMON MANIFOLD SIZE (Min.)
Models: 987 - 2067
Number of Units GPM
Diameter
2 180 4
3 270 5
4 360 6
5 450 6
6 540 6
7 630 8
8 720 8
PUMP
(in.)
NOTICE
AUTOMATIC AIR
ELIMINATOR/VENT
SYSTEM
OUTLET
SYSTEM
SENSOR
LOCATION
SYSTEM
INLET
BUFFER
TANK
DRAIN
COMMOM MANIFOLD
MUST BE SIZED TO
ACCOMMODATE COMBINED
FLOW RATE FOR
ALL BOILERS
*Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
34
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4 Water connections (continued)
Installation & Service Manual
Installation with a chilled water
system
Pipe refrigeration systems in parallel. Install duct coil
downstream at cooling coil. Where the hot water heating
boiler is connected to a heating coil located in the air handling
units which may be exposed to refrigeration air circulation, the
boiler piping system must be equipped with flow control valves
or other automatic means to prevent gravity circulation of the
boiler water during the cooling cycle.
The coil must be vented at the high point and hot water from the
boiler must enter the coil at this point. Due to the fast heating
capacity of the boiler, it is not necessary to provide a ductstat to
delay circulator operation. Also, omit thermostat flow checks
as the boiler is cold when heating thermostat is satisfied. This
provides greater economy over maintaining standby heat.
Typical heating boiler installations
General plumbing rules:
1. Check all local codes.
2. For serviceability of boiler, always install unions.
3. Always pipe pressure relief valve to an open drain.
4. Locate system air vents at highest point of system.
5. Expansion tank must be installed near the boiler and on the
suction side of the system pump.
6. Support all water piping.
TABLE - 4C
BOILER TEMPERATURE RISE AT MAXIMUM FLOW
Temperature Rise at Full Rate Fire, 55 and 90 GPM
Maximum Flow
Model Temperature Rise °F
497 15 @ 55 GPM
647 20 @ 55 GPM
747 23 @ 55 GPM
987 19 @ 90 GPM
1257 24 @ 90 GPM
1437 27 @ 90 GPM
1797 34 @ 90 GPM
2067 39 @ 90 GPM
Boiler flow rate
CAUTION
The heat exchanger is generally capable of operating within
the design flow rates of the building heating system. Should
the flow rate exceed the maximum allowable flow rate through
the boiler an external bypass must be installed. The bypass
should be fully sized with a balancing valve to allow for proper
adjustment of flow. Flow rate can be determined by measuring
the temperature rise through the boiler.
The maximum flow rate for Models 497747 is 55 GPM and 90 GPM on Models
987 - 2067. Do not exceed the maximum
flow rate of the heating boiler. If higher
flow rates are required through the boiler,
an optional Cupro-Nickel heat exchanger
is available. When using a Cupro-Nickel
heat exchanger, GPM can be increased by
30 percent. Consult the factory for specific
application requirements.
35
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4 Water connections
Installation & Service Manual
Boiler bypass requirements
The installer must ensure that the boiler is supplied with adequate
flow without excessive temperature rise. It is recommended
that this boiler be installed with a bypass in the piping if the
maximum recommended flow rate is exceeded. The bypass will
help to ensure that the boiler can be supplied with adequate
water flow. Flow rates exceeding the maximum recommended
flow will result in erosion of the boiler tubes. A typical bypass
with a valve as shown in FIG. 4-6 will allow control of boiler
flow.
Temperature / pressure gauge
This boiler is equipped with a dial type temperature / pressure
gauge. This gauge is factory installed in the outlet side of the
boiler piping. The gauge has one scale to read system pressure
and a separate scale to read water temperature in degrees
Fahrenheit. The temperature / pressure gauge is provided to
meet code requirements. Water temperatures can be more
accurately monitored from the data provided in the digital
display in the Operator Interface.
Filling the system
All air must be purged from the system for proper operation.
An air scoop and air vent must be located close to the boiler
outlet and there should be a minimum distance between the
cold water feed and the system purge valve.
1. Close all drain cocks and air vents.
2. Open the makeup water valve and slowly fill the
system.
3. If a makeup water pump is employed, adjust the
pressure to provide a minimum of 12 psi at the highest
point in the system. If a pressure regulator is also
installed in the line, it should be adjusted to the same
pressure.
4. Close all valves. Purge one circuit at a time as follows:
A. Open one circuit drain valve and let the water
drain for at least five minutes. Ensure that
there are no air bubbles visible in the water
stream before closing the drain valve.
B. Repeat this procedure for each circuit.
5. Open all valves after all circuits have been purged.
Make sure there are no system leaks.
CAUTION
6. Run the system circulating pump for a minimum of 30
minutes with the boiler turned off.
7. Open all strainers in the system and check for debris.
8. Recheck all air vents as described in step 4.
9. Inspect the liquid level in the expansion tank. The system
must be full and under normal operating pressure to
ensure proper water level in the expansion tank. Ensure
that diaphragm type expansion tanks are properly charged
and not water logged.
10. Start the boiler according to the operating instructions in
this manual. Operate the system, including the pump,
boiler and radiation units, for one hour.
11. Recheck the water level in the expansion tank. If it exceeds
half the tank volume, open the tank to reduce the water
level. Recheck pressure charge on diaphragm type tanks.
12. Shut down the entire system and vent all radiation units
and high points in the system.
13. Close the water makeup valve and check the strainer and
pressure reducing valve for sediment or debris. Reopen
the water makeup valve.
14. Verify system pressure with the boiler pressure gauge
before beginning regular operation.
15. Within three days of startup, recheck and bleed all air
vents and the expansion tank using these instructions.
Do not use petroleum based stop leak
products. All system leaks must be repaired.
The constant addition of make-up water can
cause damage to the boiler heat exchanger
due to scale accumulation. Scale reduces
flow and heat transfer, causing overheating
of the heat exchanger.
Water treatment
In hard water areas, water treatment should be used to reduce
the introduction of minerals to the system. Minerals in the
water can collect in the heat exchanger tubes and cause noise on
operation. Excessive build up of minerals in the heat exchanger
can cause a non-warrantable failure.
36
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5 Electrical connections
Installation & Service Manual
Connecting to electrical supply
This unit is wired for 120 VAC service. The unit, when
installed, must be electrically grounded in accordance with
the requirements of the authority having jurisdiction or in
the absence of such requirements, with the latest edition
of the National Electrical Code ANSI/NFPA No. 70. When
the unit is installed in Canada, it must conform to the
CAE C22.1, Canadian Electrical Code, Part 1 and/or local
Electrical Codes.
1. Use only Type-T wire [63°F (35°C) rise] on all wiring
between the unit and field-installed devices.
2. Enclose line voltage wire exterior to the unit in approved
conduit or approved metal-clad cable.
3. The pump must run continuously when the unit is
being fired (water heaters must use the pump delay if
the pump is to be cycled. See Freeze Protection, page 11
when cycling the pump). Water heaters use the
pump delay as standard in accordance with ASHRAE
90.1 requirements.
4. To avoid serious damage, do not energize the unit until the
system is filled with water.
5. Provide the unit with proper overload protection.
WARNING
ELECTRICAL SHOCK HAZARD – For your
safety, turn off electrical power supply before
making any electrical connections to avoid
possible electric shock hazard. Failure to do
so can cause severe personal injury or death.
CAUTION
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation.
TABLE 5A
AMP DRAW DATA
Model Controls Fan
497 4.6 3.4 8.0
647 4.6 3.4 8.0
747 4.6 3.4 8.0
987 4.6 3.4 8.0
1257 4.6 3.4 8.0
1437 4.6 3.8 8.4
1797 4.6 3.8 8.4
2067 4.6 3.8 8.4
Total Amps @ 120
Approximate
VAC
NOTICE
Do not block access to the electrical
cover plate when installing electrical
conduit.
Figure 5-1_Control panel location
TWO STAGE
THERMOSTAT
CONNECTION
BOARD
GROUND
SCREW
TERMINAL
STRIP
IGNITION
MODULE
MANUAL
RESET
HIGH LIMIT
24 VAC
RELAY
ON/OFF
SWITCH
24 VDC
COIL
RELAY
37
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5 Electrical connections
Installation & Service Manual
External EMS connection to terminal
strip for stage firing control of
burners
This unit is equipped with a factory installed terminal strip
for connection of an energy management system (EMS)
to the burner stages. The EMS terminal strip is located
in the unit’s control panel. Ensure that all wiring used
for connection to this terminal strip is properly sized per
the recommendations in TABLE 5A. When connecting
an EMS to this terminal strip to sequence on each stage
of burner operation, the unit’s internal thermostat or
electronic sequencer should be set as an additional high
limit control. This will prevent problems between the set
points of the EMS and the boiler’s internal controller.
Terminal strip connection options
Figure 5-2 shows the position of jumpers as shipped from
the factory for stand-alone operation of boilers or water
heaters.
Figure 5-3 shows connections to the terminal strip for
Remote ON/OFF control of the boiler or water heater.
The 1C-1NO jumper must be removed when making
these wiring connections. This remote ON/OFF control
will provide an Enable/Disable signal to the unit and allow
the unit to operate based on the stage set points, until the
remote ON/OFF signal is cancelled.
Figure 5-4 shows the connections necessary to operate the
unit as a two-stage (High/Low Fire) boiler or water heater
from an Energy Management System (EMS). The actual
set point temperatures are controlled by the EMS. The
High Fire Offset on the electronic temperature control in
the unit must be set to zero and the set point must be set
to a value which will function as an upper limit for proper
operation under this two-stage control from an EMS.
Figure 5-5 shows the Continuous and Intermittent
terminals. External safety devices connected to these
terminals will function to protect the unit. Devices
connected to the Intermittent terminals (B1 and B2) are
monitored only when there is an active Call for Heat.
Devices connected to the Continuous terminals (A1
and A2) are monitored continuously and will activate
an alarm (if the unit is equipped with the alarm option)
anytime the safety device senses an abnormal condition.
Figure 5-2_Stand-alone operation
1
+
SYSTEM/TANK
+
2
3
4
5
6
7
8
9
10
SENSOR
+
B2
INTERMITTENT
+
B1
+
A2
+
A1
+
2NO
+
2C
+
1NO
+
1C
LIMITS
CONTINUOUS
LIMITS
HIGH FIRE
ENABLE
LOW FIRE
ENABLE
6
7
8
9
10 5
1
2
3
4
Figure 5-3_Remote on/off boiler or water heater
1
+
SYSTEM/TANK
+
SENSOR
+
B2
INTERMITTENT
+
B1
+
A2
+
A1
+
2NO
+
2C
+
1NO
+
1C
LIMITS
CONTINUOUS
LIMITS
HIGH FIRE
ENABLE
LOW FIRE
ENABLE
6
7
8
9
10 5
1
2
3
4
Remote
on/off
2
3
4
5
6
7
8
9
10
Figure 5-4_Two-stage (high/low fire) boiler or water
heater
1
+
SYSTEM/TANK
+
Stage 2
2
3
4
5
6
7
8
9
10
SENSOR
+
B2
INTERMITTENT
+
B1
+
+
+
+
+
+
LIMITS
A2
A1
2NO
2C
1NO
1C
CONTINUOUS
LIMITS
HIGH FIRE
ENABLE
LOW FIRE
ENABLE
6
7
8
9
10 5
1
2
3
4
Stage 1
Figure 5-5_Field installation safety devices
38
Intermittent
Alarms
Continuous
Alarms
10
1
+
SYSTEM/TANK
+
2
3
4
5
6
7
8
9
SENSOR
+
INTERMITTENT
B2
+
B1
+
A2
+
A1
+
2NO
+
2C
+
1NO
+
1C
LIMITS
CONTINUOUS
LIMITS
HIGH FIRE
ENABLE
LOW FIRE
ENABLE
6
7
8
9
10 5
1
2
3
4
Page 39
5 Electrical connections (continued)
Installation & Service Manual
Temperature adjustment
Note: The temperature controller is preset at the factory with
test settings. You may need to adjust the settings to meet your
specific needs.
WARNING
Locating the temperature control
The temperature control is located behind the panel on the left
front of the unit (see FIG. 5-6). Follow the steps below to access
the temperature control.
1. Loosen the knurled knob at the bottom of the control
panel cover.
2. Pull the bottom of the panel out and down to remove.
Temperature control settings
There are three setting knobs on the temperature control unless
your unit is specified as a boiler only with an outdoor air reset
option. If your unit is a boiler only with an outdoor air reset
option, there are additional controls for this option. They are
explained under Outdoor Air Reset Option, page 40.
The three setting knobs on the temperature control are for Set
Point, Differential, and High-Fire Offset (see FIG. 5-7).
Maximum set point
The maximum set point for the control is factory set. Boilers
are set to 230°F max., water heaters are set to 190°F max., and
specialty state and local codes to 200°F.
These maximum set points are established by not cutting/
cutting the OJ1 and OJ2 jumpers located on the right side of the
temperature controller (see FIG. 5-7). The maximum set point
is determined as shown in Table 5B.
Figure 5-6_Locating temperature control
TEMPERATURE
CONTROL
Return water temperatures must not be less
than 140°F. If lower return water temperatures
are required, follow the instructions for Low
Temperature Return Water Systems on page
30.
Figure 5-7_Temperature control setting knobs
SETPOINT
DIFFERENTIAL
HIGH-FIRE
OFFSET
TABLE 5B
Maximum Setpoint Determination
OJ1 OJ2
Connected Connected 230°
Cut Connected 190°
Connected Cut 200°
Cut Cut 160°
NOTICE
Anytime that OJ1 is the only jumper cut, a
new overlay is required under the Set Point
knob on the temperature controller because
the scale has changed to a maximum of
190°F.
Anytime the OJ2 jumper is cut (with or
without OJ1), a new overlay is required
under the Set Point knob on the temperature
controller because the scale has changed to
a maximum of 200°F.
Setpoint
OJ1
OJ2
Max.
OJ1
OJ2
39
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5 Electrical connections
Installation & Service Manual
Setpoint
The Set Point knob specifies the target water temperature in
degrees, Fahrenheit. After the water temperature reaches the set
point, the temperature control shuts off the burners.
Differential
The Differential specifies the number of degrees below the set
point that the control will allow the water temperature to drop
before it brings the unit back on again.
High-fire offset
The temperature control operates a two-stage firing system.
The two stages are High-Fire and Low-Fire. High-Fire operates
all burners while Low-Fire operates approximately one-half of
the burners.
The High-Fire knob specifies the number of degrees below set
point that the High-Fire stage shuts down. At that point, the
unit will continue to operate at the Low-Fire stage until the set
point is reached.
The High-Fire offset knob has settings between 0°F and 20°F.
If set at 0°F, the High-Fire offset is disabled and the unit will
operate at the High-Fire stage until the set point is reached and
the temperature control shuts the unit off.
When the High-Fire offset knob is set to 0 or 1, the unit will
light at Low Fire and operate for approximately 10 seconds
before the High-Fire stage actuates. When set to 2 or above, the
unit will operate at Low Fire for 2 minutes before the High Fire
stage can actuate.
Figure 5-8_Optional outdoor reset control
SHUTDOWN
OUTDOOR
AIR
SHUTDOWN
OUTDOOR
AIR
SENSOR
Outdoor reset option
For boilers ordered with the Outdoor Air Reset option, there
is an additional control (see FIG. 5-8). There are three setting
knobs for Shutdown, Outdoor Air Max., and Ratio. There is
also a switch to turn the outdoor air sensor On or Off. An O.A.
Sensor is also included.
Shutdown
The Shutdown knob specifies the outdoor air shutdown
temperature at which the control would prevent the unit from
operating. This feature can be enabled/disabled with the O.A.
Shutdown switch.
Outdoor air max (O. A. Max)
The O. A. Max knob allows a reset up to the maximum outdoor
air temperature specified by this knob setting. When the
outdoor air temperature is above the specified setting, the unit
will not function in the O.A. Reset Mode, but will continue to
run at the selected set point temperature.
Note that the set point knob will now indicate the “minimum”
boiler temperature. Target temperature is determined by the
ratio and outdoor air temperature below the O.A. Max setting.
Ratio
The Ratio knob allows the control over the reset ratio to be used
during Outdoor Air Reset. The allowable ratios are as low as
0.5:1 or as high as 1.5:1.
Selecting the 0.5:1 ratio will increase the set point 0.5°F for every
1.0°F drop in outdoor air temperature up to the maximum set
point temperature.
Selecting the 1.5:1 ratio will increase the set point 1.5°F for every
1.0°F drop in outdoor air temperature up to the maximum set
point temperature (see page 39).
See FIG. 5-10 for an outdoor air reset chart example.
40
AIR
MAX
RATIOOUTDOOR
Page 41
5 Electrical connections (continued)
Temperature control sensors
This is a two-stage temperature control that controls the
burner ignition, pump, and alarm functions. This temperature
controller can measure up to three different sensor inputs,
depending upon how the unit is set up. They are as follows:
1. Inlet Water Temperature Sensor
2. Multi-Purpose Temperature Sensor
3. Outside Air Temperature Sensor
Inlet water temperature sensor
This sensor measures the inlet water temperature coming into
the unit.
Multi-purpose temperature sensor
This sensor can be used as a system sensor or a tank sensor.
Outdoor air temperature sensor
This sensor is only available on boiler units with an outdoor
air reset option. This allows you to tie boiler operation to
the outdoor air temperature. As outside temperatures drop,
the control will increase the temperature setting of the boiler.
As outdoor temperatures rise, the control will decrease the
temperature to the selected set point of the boiler. You can set
the control to shut the boiler off when a desired outdoor air
temperature level is reached.
Remote sensor for pump delay
This appliance is provided with a special thermostat sensor
that MUST be field installed. The sensor is shipped loose in
the I & O packet. This remote mounted sensor will be the
primary water sensor which will inform the appliance's builtin thermostat control. Reading the water temperature at the
remote location is required for proper operation of the pump
delay option provided with this appliance.
For domestic water heating, the sensor must be installed into a
bulbwell on the storage tank. For boiler and hydronic heating,
the sensor must be installed in the system piping loop. If the
appliance is controlled by a remote sequencer, the sensor must
be routed back into the appliance and placed in a bulbwell on
the inlet side of the heat exchanger.
The sensor must be connected to two wires provided on the side
of the appliance with the water connections (FIG. 5-9). It will
be necessary to add additional wire to reach from the appliance
to the remote water source. Use twisted pair wire or minimum
18 gauge wire or larger. Reference Table 5C on page 42 for a
chart regarding distance versus wire gauge.
Boiler application
Standard boiler units are shipped with two sensors; the inlet
water temperature sensor and the multi-purpose temperature
sensor. The multi-purpose sensor should be used as a system
sensor. Boilers with the outdoor air reset option also have an
outside air temperature sensor.
Water heater application
Water heater units are shipped with two sensors; the inlet water
temperature sensor and the multi-purpose temperature sensor
to be used as a tank sensor.
Placement of sensors
Inlet temperature sensor
The inlet water temperature sensor is installed by the factory in
new units. The sensor is an immersion style and maintains direct
contact with the water.
System sensor
This is used for boiler applications. This sensor will control the
boiler operation based upon the water temperature within the
building loop.
Tank sensor
This is used in water heating applications. Place the sensor in
the water storage tank to measure water temperature. For more
information on mounting the sensor, see Remote Mounting of
Sensors, page 42.
Outdoor air Temperature sensor
The outside air temperature sensor will only be used for boiler
systems. The outside air sensor is optional. You must purchase
the sensor from the appliance manufacturer. The sensor comes
with a housing that helps protect the sensor from the elements.
Mount the air sensor housing under the eve of the roof. Make
sure the housing is out of direct sunlight. This will ensure that
the sensor will accurately read the true outdoor temperature.
For more information on mounting the sensor, see Remote
Mounting of Sensors, page 42.
Figure 5-10_Outdoor air reset chart example
Installation & Service Manual
Figure 5-9_Remote sensor for pump delay
FIELD SUPPLIED
WIRING
SYSTEM/
TANK
SENSOR
REQUIRED IN ORDER
FOR PUMP DELAY TO
FUNCTION PROPERLY
CONNECTION BOARD
1
+
SYSTEM/TANK
+
2
3
4
5
6
7
8
9
10
+
+
+
+
+
+
+
+
SENSOR
B2
B1
A2
A1
2NO
2C
1NO
1C
INTERMITTENT
LIMITS
CONTINUOUS
LIMITS
HIGH FIRE
ENABLE
LOW FIRE
ENABLE
6
7
8
9
10 5
1
2
3
4
41
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5 Electrical connections
Installation & Service Manual
Remote mounting of a sensor
You must mount the outside air temperature sensor outside
the building. To mount remote sensors, follow the guidelines
below. Take care to correctly wire sensors to the unit. Erratic
temperature readings can be caused by poor wiring practices.
Twist the wires between the unit and the remote sensor. Turn
wires at least three or four turns per linear foot of wiring. This
provides common mode rejection of some types of electrical
interferences.
1. Do not route temperature sensor wiring with building
power wiring.
2. Do not locate temperature sensor wiring next to control
contactors.
3. Do not locate temperature sensor wiring near electric
motors.
4. Do not locate temperature sensor wiring near welding
equipment.
5. Make sure good mechanical connections are made to the
sensor, any interconnecting wiring and the controller.
6. Do not mount sensor with leadwire end pointing up in an
area where condensation can occur.
7. Use shielded wiring to connect the sensor to the control
when the possibility of an electrically noisy environment
exists. Shielded cable is recommended on all cable runs of
more than 25 feet in length.
NOTICE
Ground the cable shield at the connection
to the boiler temperature control only. Do
not ground the shielded cable at the sensor
end.
To maintain temperature accuracy, sensor
wires should be at least 18 AWG, see Table
5C.
TABLE 5C
Remote Wire Connection
Wire Gauge Max. Allowable Length
12 GA 100 FT
14 GA 75 FT
16 GA 50 FT
18 GA 30 FT
Hot surface ignition system
Hot surface igniter and ignition control
module
This unit has one ignition module and one hot surface igniter.
Figure 5-11_Hot surface igniter
CAUTION
Hot surface ignition control module
Ignition Module Lockout Functions
The ignition module may lockout in either a hard-lockout
condition, requiring pushing of the reset button to recycle
the control, or a soft-lockout condition which may recycle
after an approximate five-minute waiting period. This softlockout condition is intended to allow self-correcting faults
to correct themselves and permit normal operation. A typical
hard-lockout fault is a flame failure condition. An ignition
module that is in a hard-lockout condition may only be reset
by pushing the reset button next to the ignition control or the
“RESET” button on the diagnostic panel on the left end of
the unit. Upon a flame failure, the reset button is only active
after the control module has completed its post-purge cycle.
Turning main power “OFF” and then “ON” or cycling the
thermostat will not reset a hard-lockout condition. Wait five
seconds after turning on main power before pushing the reset
button when the ignition module is in a hard lockout. The
ignition module will go into a soft lockout if conditions of low
air, low voltage or low hot surface igniter current are present.
A soft-lockout condition will operate the combustion air fans
for the post purge cycle and then the ignition module will
pause for approximately five minutes. At the end of this timed
pause, the ignition module will attempt a new trial for ignition
sequence. If the soft-lockout fault condition has subsided or
has been corrected at the end of the timed pause, main burner
ignition should be achieved with the resumption of the normal
trial for ignition sequence. If the control sensed fault is not
corrected, the ignition module will continue in the soft-lockout
condition. If the electronic thermostat opens during the softlockout period, the ignition module will exit soft lockout and
wait for a new call for heat from the thermostat. A soft-lockout
condition may also be reset by manually cycling the thermostat
or turning the main power switch “OFF” and then “ON” after
the control sensed fault has been corrected.
The igniter is extremely fragile, be very
careful when removing. A faulty or damaged
hot surface igniter MUST BE replaced with
a Lochinvar PLT3400 igniter. Do not use
general purpose field replacement igniters.
42
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5 Electrical connections (continued)
Installation & Service Manual
Diagnostic Status Indication
The ignition module has an LED which indicates the status of the
safety circuits. A remote Ignition Module Status indicating light
is wired from the ignition module Status LED and mounted on
the front diagnostic panel. The flashing operation of this light
indicates the diagnostic status of the ignition control module.
The status LED, mounted on the ignition module flashes a code
sequence from the Ignition Module to indicate the status of the
ignition process. See Table 5D for the flashing diagnostic status
codes as signaled by the ignition module.
Ignition and control timings
Proven Pilot Hot Surface Ignition System is standard on all
models.
Hot Surface Ignition Module Timings (Nominal)
Prepurge:
15 Seconds
Hot Surface Igniter Heat-up Time:
25- 35 seconds
Main Burner Flame Establishing Period:
4 Seconds
Failure Response Time:
0.8 Seconds at less than 0.5 µA flame current
Flame Current:
2 - 6 µA
Time Delay Between Stages 1&2:
10 or 120 Seconds (depending on high fire offset settings)
Post-purge:
30 Seconds
Pump Delay Timing:
30 Seconds after burner shutdown.
Figure 5-12_Hot surface ignition control module
43
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5 Electrical connections
Installation & Service Manual
Operation and diagnostic lights
The diagnostic control panel has up to 6 indicating and
diagnostic lights to show all major steps of operation and
control sensed malfunctions. This panel is located on the front
of the unit.
TABLE 5D
Status LED Diagnostic Codes
Code
Sequence
Constant
ON
Constant
OFF
One
Flash
System OK, no faults present.
Possible control fault, check power; LED may
be defective, do not replace control if all
operational sequences function properly, see
Trouble- Shooting Guide.
Low Air, check air pressure switch and hoses
to pressure sensing points, fan, venting and
sealing of pressurized chamber. Note: Brief
flashing normal on fan start-up proving.
Condition
TABLE 5E
Status LED Diagnostic Codes
Code
Sequence
Prepurge
Trial for
Ignition
Stage 1 ON Burners for stage 1 operating.
Stage 2 ON
Status Remote status light for ignition module.
Alarm
Operation for combustion air fan before ignition
on stages 1 and 2.
Hot surface igniter preparing to light burners.
Burners for stage 2 operating.
Indicates flame failure on the ignition module
and will indicate additional alarms if the alarm
of any failure option is purchased.
Condition Lights
Two
Flashes
Three
Flashes
Four
Flashes
Five
Flashes
Six
Flashes
Flame without call for heat, check for a gas
valve stuck in the open position, air, venting,
burners and the combustion process. Fan will
remain on.
Lockout due to flame failure, push reset
button on the diagnostic panel after correcting
ignition problem. Initial heater start up
without properly bleeding air from the gas
line may require multiple reset functions to
achieve proper ignition.
Igniter failure, igniter will not maintain a
minimum 2.75 amp current draw, caused
by low voltage, bad wiring/continuity, high
resistance or igniter failure.
Power supply problem, check for low supply
voltage or transformer output less than 18VAC.
Replace ignition module, internal fault.
Figure 5-13_Operation / diagnostic lights
44
Page 45
6 Startup
Figure 6-1_Operating instructions
FOR YOUR SAFETY READ BEFORE OPERATING
Installation & Service Manual
WARNING:
If you do not follow these instructions
exactly, a fire or explosion may result causing
property damage, personal injury or loss of life.
A. This appliance is equipped with an ignition
device which automatically lights the burner.
Do not
try to light the burner by hand.
B. BEFORE OPERATING smell all around the
appliance area for gas. Be sure to smell next
to the floor because some gas is heavier
than air and will settle on the floor.
"WHAT TO DO IF YOU SMELL GAS"
Do not try to light any appliance.
Do not touch any electrical switch; do not use
any phone in your building.
Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's
instructions.
1. STOP! Read the safety information above on
this label.
2. Turn off all electric power to the appliance.
3. Open control access panel.
4. This appliance is equipped with an ignition
device which automatically lights the burner.
Do not
try to light the burner by hand.
SHOWN IN THE "ON" POSITION
FOR YOUR SAFETY
PSI
IN
OPERATING INSTRUCTIONS
ON
OFF
GAS CONTROL KNOB
If you cannot reach your gas supplier,
call the fire department.
C. Use only your hand to turn the gas
control knob. Never use tools. If the
knob will not turn by hand, don't try to
repair it, call a qualified service technician. Force or attempted repair may
result in a fire or explosion.
D. Do not use this appliance if any part
has been under water. Immediately call
a qualified service technician to inspect
the appliance and to replace any part
of the control system and any gas control which has been under water.
5. Push in gas control knob slightly and
turn clockwise to "OFF."
NOTE: On the 36C valve, knob cannot be
turned to "OFF" unless knob is pushed in
slightly. Do not force.
6. Wait five (5) minutes to clear out any gas.
Then smell for gas, including near the floor. If
you smell gas, STOP! Follow "B" in the safety
information above on th
smell gas, go to the next step".
7. Turn gas control knob counterclockwise
8. Replace control access panel.
9. Turn on all electric power to the appliance.
10. If the appliance will not operate, follow
the instructions "To Turn Off Gas To
Appliance" and call your service tech-
nician or gas supplier.
OFF
to "ON."
ON
OFF
ON
is label. If you don't
TO TURN OFF GAS TO APPLIANCE
1. Turn off all electric power to the appliance
if service is to be performed.
2. Open control access panel.
3. Push in gas control knob slightly and
turn clockwise to "OFF". Do not
force.
4. Replace control access panel.
OFF
ON
LBL2084 REV D
45
Page 46
6 Startup
Installation & Service Manual
Check/control water chemistry
CAUTION
Hardness less than 7 grains
1. Consult local water treatment companies for hard water
areas (above 7 grains hardness).
Chlorine concentration less than 200 ppm
1. Do not fill boiler or operate with water containing chlorine
in excess of 200 ppm.
2. Filling with chlorinated fresh water should be acceptable
since drinking water chlorine levels are much lower.
3. Do not use the boiler to directly heat swimming pool or spa
water.
Test/replace freeze protection fluid
1. For systems using freeze protection fluids, follow fluid
manufacturer’s instructions.
2. Freeze protection fluid must be replaced periodically due
to degradation of inhibitors over time. Follow all fluid
manufacturer’s instructions.
Do not use petroleum-based cleaning or
sealing compounds in the boiler system.
Damage to elastomer seals and gaskets in the
system could occur, resulting in substantial
property damage.
Freeze protection (when used)
1. Determine freeze protection fluid quantity using system
water content, following fluid manufacturer’s instructions.
Appliance water content is listed on pages 8 and 9.
Remember to include expansion tank water content.
2. Local codes may require a backflow preventer or actual
disconnect from city water supply.
3. When using freeze protection fluid with automatic fill,
install a water meter to monitor water makeup. Freeze
protection fluid may leak before the water begins to
leak, causing concentration to drop, reducing the freeze
protection level.
Fill and test water system
1. Fill system only after ensuring the water meets the
requirements of this manual.
b. Pressure will rise when boiler is turned on and
system water temperature increases.
4. At initial fill and during boiler startup and testing, check
system thoroughly for any leaks. Repair all leaks before
proceeding further.
WARNING
Eliminate all system leaks. Continual
fresh makeup water will reduce boiler life.
Minerals can build up in the heat exchanger,
reducing heat transfer, overheating the heat
exchanger, and causing heat exchanger
failure.
Purge air from water system
1. Purge air from system:
a. Connect a hose to the purge valve. Route the hose to an
area where water can drain and be seen.
b. Close the boiler or system isolation valve between
the purge valve and fill connection to the system.
c. Close zone isolation valves.
d. Open quick-fill valve on cold water makeup line.
e. Open purge valve.
f. One zone at a time, open the isolation valves. Allow
water to run through the zone, pushing out the air.
Run until no noticeable air flow is present. Close the
zone isolation valves and proceed with the next zone.
Follow this procedure until all zones are purged.
g. Close the quick-fill water valve and purge valve and
remove the hose. Open all isolation valves. Watch
that system pressure rises to correct cold-fill
pressure.
h. After the system has operated for a while, eliminate
any residual air by using the manual air vents located
throughout the system.
i. If purge valves are not installed in the system, open
the manual air vents in the system one at a time,
beginning with the lowest floor. Close the vent when
water squirts out. Repeat with remaining vents.
2. Open automatic air vent (diaphragm-type or bladder-type
expansion tank systems only) one turn.
3. Open other vents:
a. Starting on the lowest floor, open air vents one at a
time until water squirts out.
b. Repeat with remaining vents.
4. Refill to correct pressure.
2. Close manual and automatic air vents and boiler drain
valve.
3. Fill to correct system pressure. Correct pressure will vary
with each application.
a. The minimum cold water fill pressure should be
12 PSI.
46
Page 47
6 Startup (continued)
Check for gas leaks
Installation & Service Manual
WARNING
WARNING
Before starting the boiler, and during initial
operation, smell near the floor and around
the boiler for gas odorant or any unusual
odor. Remove the front access panel and smell
the interior of the boiler enclosure. Do not
proceed with startup if there is any indication
of a gas leak. Use an approved leak detection
solution. Repair any leaks at once.
Propane boilers only – Your propane supplier
mixes an odorant with the propane to make
its presence detectable. In some instances, the
odorant can fade, and the gas may no longer
have an odor. Before startup (and periodically
thereafter), have the propane supplier verify
the correct odorant level in the gas.
Check thermostat circuit(s)
1. Disconnect the two external wires connected to the enable
terminals on the connection board.
2. Connect a voltmeter across these two incoming wires.
Close each thermostat, zone valve, and relay in the external
circuit one at a time and check the voltmeter reading across
the incoming wires.
3. There should NEVER be a voltage reading.
4. If a voltage does occur under any condition, check and
correct the external wiring. (This is a common problem
when using 3-wire zone valves.)
5. Once the external thermostat circuit wiring is checked and
corrected if necessary, reconnect the external thermostat
circuit wires to the connection board. Allow the boiler to
cycle.
Check vent and air piping
1. Inspect vent piping and air piping for signs of
deterioration from corrosion, physical damage or
sagging. Verify air piping and vent piping are intact
and correctly installed per this manual.
Boiler operation
8. Verify that all adjustable points in the Operator
Interface are set as required.
9. Boiler should begin the start-up process for the
sequence of operation.
10. The boiler will ignite and operate to meet the system
demand.
11. Ensure that inlet water temperature does not fall below
the specified minimum for the boiler.
12. As system demand is satisfied, the burner will cycle off
and the combustion air blower will run for a post
purge operation before the boiler shuts down.
Start the boiler
1. Read and follow the Lighting Instructions in FIG. 6-1, on
page 45.
If boiler does not start correctly
1. Check for loose connections, blown fuse or service switch
off?
2. Is external limit control (if used) open? Is boiler water
temperature above 200°F (93.3°C)?
3. Is thermostat set below room temperature?
4. Is gas turned on at meter or boiler?
5. Is incoming gas pressure less than 4 inches water column?
If none of the above corrects the problem, refer to the
Maintenance Section of this manual.
WARNING
The venting system must be installed so that
it will prevent flue gas spillage and carbon
monoxide emissions, which will result in
severe personal injury or death.
Placing the boiler in operation
Boiler operational checks
2. Turn the boiler main power switch to the “ON”
position.
3. Confirm the settings of the temperature control.
4. Push the reset for the low water cutoff (if equipped).
5. Ensure that maximum flow to the boiler does not exceed
55 GPM on Models 402 - 752 and 90 GPM on Models
992 - 2072. Verify by checking temperature rise while
burner is firing at 100% of rated input.
6. Install a manometer on the gas supply to the boiler and
verify minimum gas supply pressure as the burner fires at
100% of rated input.
7. Verify operation of safeties as necessary (low water
cutoff, high limit, gas pressure, etc.,).
47
Page 48
Installation & Service Manual
7 Domestic water heaters
This section applies only to those units used to supply potable hot water for domestic use. The water heater must be installed
with a storage tank.
This section contains specific instructions for those units used to supply domestic hot water. All warnings, cautions, notes
and instructions in the general installation and service sections apply to these instructions. Water heaters are designed for
installation with a properly sized storage tank. The use of a properly sized pump and the control of water velocity, as explained
below, are important for correct operation of your water heater.
Water velocity control
NOTICE
To ensure proper velocity through the
heat exchanger, you must regulate the
temperature rise across the heat exchanger
from inlet to outlet. Do this upon initial
installation and periodically recheck.
The correct temperature rise across the
heat exchanger ensures proper velocity
in the tubes. This will yield long life and
economical operation from your hot water
heater. Excessive lime build up in the
tube is caused by too low velocity through
the tubes. Excessive pitting or erosion in
the tube is caused by too high velocity
through the tubes. Take care to measure
temperature rise and maintain a velocity
as follows:
Initial set-up of maximum water flow
On initial start-up, the maximum water flow through
the heat exchanger must be manually set before normal
operation begins.
TABLE - 7A
MAXIMUM WATER FLOW
CAUTION: The maximum flow rate through a water
heater with a copper heat exchanger must be set to provide
and not exceed the following flow:
Model
497, 647, and 747 55 GPM
987, 1257, 1437, 1797, and 2067 90 GPM
If higher flow rates are required through the water heater,
an optional Cupro Nickel heat exchanger is available.
Consult the factory for specific application requirements.
The heat exchanger is capable of operating within the design
flow rates required for the water heater, storage tank(s), and
connecting piping. Erosion of the finned copper tubes may
occur if the flow rate exceeds the maximum allowable flow
rate through the water heater. The maximum flow rate
through the water heater must be adjusted. Maximum
flow on Models 497 - 747 is 55 GPM and 90 GPM on Models
987 - 2067. Flow rate can be determined by measuring the
temperature rise through the water heater when it is firing
at full rate input.
Maximum
Flow
48
TABLE 7B
Temperature Rise Chart
Model
497 15°F
647 19°F
747 22°F
987 18°F
1257 23°F
1437 26°F
1797 32°F
2067 37°F
1. With the pump running and the water heater off,
the inlet and outlet thermometers should read the same
temperatures. If they do not, an adjustment must be
made to your final calculation.
2. Turn the water heater “On” and allow time for the
temperature to stabilize. Record the difference between
the inlet and outlet temperatures. This difference will
be the “temperature rise”.
3. Compare the temperature rise on the heater with the
required temperature rise in Table 7B. Should
adjustment be needed, proceed as follows:
If the temperature rise is too high, the water velocity is too
low. Check the following:
1. Check for restrictions in the outlet of the water heater.
2. Be sure all valves are open between the water heater and
the tank.
3. Check the pump to be sure it is running properly and
that the pump motor is running in the proper direction
(see arrow on volute housing).
4. Be sure the installed circulation pipes between the
water heater and storage tank are not less than 2 1/2'' in
diameter on Models 987 - 2067.
5. Common manifold piping for multiple unit installations
will require larger minimum pipe sizes and tank
circulating tappings to ensure proper flow. See Table
7C on page 53.
If the temperature rise is too low, the water velocity is too
high. Adjust as follows:
1. Slowly throttle the valve on the outlet side of the water
heater until the temperature rise is steady at the required
temperature rise as noted in Table 7A.
2. Sustained high water velocity and low temperature rise
may result in pitting or erosion of the copper tubes in the
heat exchanger. This is a non-warrantable failure.
Temperature rise must be properly adjusted to achieve the
specified flow rate.
Temperature
Rise
Page 49
7 Domestic water heaters (continued)
Figure 7-1_Typical water heater piping with storage tank
Installation & Service Manual
COMMON MANIFOLD SIZE (Min.)
Models: 497 - 747
Number of Units GPM
Diameter
(in.)
1 60 2 1/2
BUILDING
HOT WATER
SUPPLY
MIXING
VALVE
COLD
WATER
SUPPLY
COMMON MANIFOLD SIZE (Min.)
Models: 987 - 2067
Number of Units GPM
1 90 2 1/2
RELIEF
VALVE
INLET
Diameter
(in.)
RELIEF
VALVE
LOCK-TEMP
STORAGE
TANK
NOTICE
OUTLET
BUILDING
RETURN
DRAIN
*Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
49
Page 50
7 Domestic water heaters
Figure 7-2_Single water heater piping with two storage tanks
Installation & Service Manual
COMMON MANIFOLD SIZE (Min.)
Models: 497 - 747
Number of Units GPM
Diameter
(in.)
1 60 2 1/2
BUILDING
HOT WATER
SUPPLY
RELIEF
VALVE
MIXING
VALVE
OUTLET
COMMON MANIFOLD SIZE (Min.)
Models: 987 - 2067
Number of Units GPM
1 90 2 1/2
INLET
Diameter
(in.)
COLD
WATER
SUPPLY
LOCK-TEMP
STORAGE
TANK
DRAIN
NOTICE
50
BUILDING
RETURN
*Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
Page 51
7 Domestic water heaters (continued)
Figure 7-3_Multiple water heater piping with a single storage tank
Installation & Service Manual
COMMON MANIFOLD SIZE (Min.)
Models: 497 - 747
Number of Units GPM
2 120 3 1/2
3 180 4
4 240 5
5 300 5
6 360 6
7 420 6
8 480 6
BUILDING
HOT
WATER
SUPPLY
Diameter
(in.)
MIXING
VALVE
COLD
WATER
SUPPLY
COMMON MANIFOLD SIZE (Min.)
Models: 987 - 2067
Number of Units GPM
2 180 4
3 270 5
4 360 6
5 450 6
6 540 6
7 630 8
8 720 8
Diameter
(in.)
RELIEF
VALVE
LOCK-TEMP
STORAGE
TANK
NOTICE
MIN 4"
COMMON
MANIFOLD
SIZE
DRAIN
BUILDING
RETURN
*Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
51
Page 52
7 Domestic water heaters
Figure 7-4_Multiple water heater piping with multiple storage tanks
Installation & Service Manual
COMMON MANIFOLD SIZE (Min.)
Models: 497 - 747
Number of Units GPM
2 120 3 1/2
3 180 4
4 240 5
5 300 5
6 360 6
7 420 6
8 480 6
Diameter
(in.)
MIXING
VALVE
COLD
WATER
SUPPLY
COMMON MANIFOLD SIZE (Min.)
Models: 987 - 2067
Number of Units GPM
2 180 4
3 270 5
4 360 6
5 450 6
6 540 6
7 630 8
8 720 8
Diameter
(in.)
BUILDING
HOT
WATER
SUPPLY
RELIEF
VALVE
LOCK-TEMP
STORAGE
TANK
MIN 4"
COMMON
MANIFOLD
SIZE
DRAIN
BUILDING
RETURN
NOTICE
52
*Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
Page 53
7 Domestic water heaters (continued)
Installation & Service Manual
Required temperature rise
Based on heating potable water with a hardness of 5 to
25 grains per gallon and/or total dissolved solids not
exceeding 350 ppm, see Water Chemistry, this page.
Water chemistry
The required temperature rise and the standard pump sizing
are based on the heating of potable water with a hardness
of 5 to 25 grains per gallon and a total dissolved solids not
exceeding 350 ppm. Consult the appliance manufacturer
when heating potable water exceeding these specifications.
Heating of high hardness and/or high total dissolved solids
water will require a larger circulating pump, an optional
cupro-nickel heat exchanger and a revised temperature rise
specification based on the water chemistry of the water to
be heated.
Water with a hardness of less than 5 grains per gallon will
usually have a low pH which can be aggressive and corrosive
causing non-warrantable damage to the heater, pump and
associated piping. Corrosion due to water chemistry generally
shows up first in the hot water system because heated water
increases the rate of corrosive chemical reactions.
Pipe size requirements
Circulating pump
1. The water heater must be connected to a properly sized
pump that circulates water between the heater and
storage tank.
2. The pump is sized to heater input and water hardness.
Care should be taken to size the pump correctly. See
Water Chemistry, this page.
3. The water heater is equipped with a factory-supplied
pump delay system in accordance with the requirements
of the latest edition of ASHRAE 90.1.
4. Lubricate the pump to the manufacturer’s
recommendations. Pump damage due to inadequate
lubrication is non-warrantable.
5. Standard water heaters are furnished with the following
circulating pump. Mount the pump on the unit’s inlet
water connection.
Models 497 - 747
1/4 HP, 120 VAC, 5.8 Amps
Models 987 - 2067
1/2 HP, 120 VAC, 7.4 Amps
Table 7B, pipe sizing chart provides the minimum pipe size
for common manifold piping to ensure adequate flow.
TABLE 7C
Pipe Sizing Chart
497 - 747 987 - 2067
Number of
Units
1 2'' 1 2 1/2''
2 3'' 2 4''
3 3'' 3 4''
4 4'' 4 5''
5 5'' 5 6''
6 5'' 6 6''
Common Pipe
Size (Min.)
Number of
Units
Common Pipe
Size (Min.)
This pump is sized based on installation of a single storage
tank and heater in close proximity. If the number of fittings
and straight pipe exceeds the quantities shown in this section, a
larger pump will be required.
The standard pump selection is based on the following pipe and
fittings from the unit to the storage tank:
• 6 90° elbows
• 2 unions
• 2 ball valves
• 1 cold water tee
• No more than 45
feet of straight pipe.
NOTICE
For every elbow and tee in excess of those shown
above, deduct 5 feet from maximum allowable
straight pipe in heater to tank circulating loop.
53
Page 54
7 Domestic water heaters
Installation & Service Manual
Minimum pump performance
This is based on heating potable water with a hardness of
5 to 25 grains per gallon and/or total dissolved solids not
exceeding 350 ppm. See Water Chemistry, page 53.
TABLE 7D
Minimum Pump Performance
Model GPM FT/HD
497 - 747 55 10
987 - 2067 90 15
Heat exchanger
This is a highly sophisticated heat exchanger, designed
to carry water in such a way that it generates a scouring
action which keeps all interior surfaces free from build
up of impurities. The straight line, two pass design of
the tubes sends water into the headers at a properly
rated velocity. The configuration of the headers, in turn,
creates a high degree of turbulence which is sufficient
to keep all contaminants in suspension. This “scouring
action” provides greater cost savings for owners.
Tubes are always able to transfer heat at peak efficiency.
Every surface within this water containing section is of a
non ferrous material, providing clear, clean, rust free hot
water. Straight copper tubes finned on the outside for
maximum heat transfer and coated cast iron one piece
cored headers make up an entirely rust proof unit. On all
models, header inspection plugs can be removed for field
inspection and cleaning of copper tubes. The entire heat
exchanger may be easily removed from the unit.
Potable hot water temperature
control settings
Domestic water temperature
WARNING
This unit has an adjustable temperature control to maintain the
desired water temperature set point. See Setting Temperature
Control, page 39, for instructions to adjust the temperature
control. The temperature control is factory preset at
approximately 125°F (52°C) or less. Households with small
children or invalids may require 120°F (49°C) or lower
temperature hot water to reduce risk of scald injury.
Operate this high efficiency hot water heater at a temperature
setting high enough to prevent condensing of the products of
combustion on the unit’s heat exchanger or in the attached
venting system. A water temperature setting that is above the
dew point of the gas combustion products should prevent
condensate formation
WARNING
WARNING
You must take adequate care to prevent
scald injury when storing water at elevated
temperatures for domestic use.
To guard against scald injury, you must use a
properly sized thermostatic mixing valve to
supply domestic hot water at temperatures
less than 125°F (52°C).
Return water temperatures must not be
less than 140°F (60°C). If lower return
water temperatures are required, follow the
instructions for Low Temperature Return
Water Systems, page 30.
54
Page 55
Installation & Service Manual
7 Domestic water heaters (continued)
Storing the water at a higher temperature and thermostatically
mixing the water increases the available quantity of mixed hot
water, greatly reducing the possibility of condensate forming
on the heat exchanger or in the venting system and helps
prevent water born bacteria growth.
Some states may require a lower water temperature setting for
specific applications. Check local codes or your gas supplier for
domestic hot water temperature requirements.
• Water temperature over 125°F (52°C)
can cause severe burns instantly or
death from scalds.
• Children, disabled and elderly are
at highest risk of being scalded.
• See instruction manual before
setting temperature at heating
appliance.
• Feel water before bathing or showering.
• If this appliance is used to produce
water that could scald if too hot,
such as domestic hot water use,
adjust the outlet control (limit) or use
temperature limiting valves to obtain
a maximum water temperature of
125°F (52°C).
Remember, no water heating system provides exact temperatures
at all times. Let the system operate a few days at your desired
settings to determine correct settings for your needs.
NOTICE
The High-Fire stage will be delayed by
approximately 10 seconds to allow a
soft start of the water heater.
WARNING
When water is stored at temperatures
above 125°F (52°C), a thermostatic
mixing valve must be installed on the
hot water outlet from the storage tank
to supply lower temperature water and
prevent the risk of a scald injury.
This water heater, when set at a lower
NOTICE
temperature setting, is not capable
of producing hot water of sufficient
temperature for sanitizing purposes.
Location of cold water supply piping
connections
Incorrect piping of the cold water supply to the system
may result in excessive low temperature operation
causing condensate formation on the heat exchanger and
operational problems. You must install the cold water
supply piping in the discharge piping from the heater to the
storage tank. This allows the cold water to be tempered in
the storage tank before entering the heater. See FIG. 7-1, on
page 49, and typical installation drawings provided with the
unit for correct piping. Higher water temperatures reduce
condensate formation.
1. These units are equipped with an operating temperature
control.
2. The control set points are preset to a low test setting when
shipped from the factory.
3. Reset the temperature set points to the lowest settings which
will satisfy hot water demands, eliminate a possible
condensate problem and prevent a risk of scald injury.
4. The High-Fire Offset should normally be adjusted to “0”
when supplying potable hot water for domestic use.
5. Stage firing can be achieved by adjusting the High-Fire
Offset to any value other than zero. Typically, a setting of
3°F is 5°F is suitable for stage firing in a water heater
application. Stage firing of a potable water heater is
normally only used to replace system standby heat loss.
6. All stages of burner operation should fire when there is a
major draw from the potable hot water storage system.
This prevents possible condensate problems and ensures a
rapid recovery of the hot water used.
WARNING
Should overheating occur or the gas
supply fail to shut off, do not turn off
or disconnect the electrical supply to
the pump. Instead, shut off the gas
supply at a location external to the
unit.
55
Page 56
7 Domestic water heaters
High water temperature limit control
The unit is equipped with an adjustable setting, auto-reset
high water temperature limit control. The hot water heater
temperature limit control has a maximum limit setting of
200°F (93°C). If water temperature exceeds the set point,
the limit will break the control circuit and shut down the
unit. The limit control will only be reset after the water
temperature has cooled below the set point of the limit.
The high water temperature limit control is mounted in
the outlet side of the front header. A manual reset high
water temperature limit control is available as an optional
control.
Optional relief valve
This water heater is normally supplied with a temperature
and pressure relief valve(s) sized in accordance with
applicable codes. Units may be supplied with an optional
pressure only relief valve(s). When a water heater equipped
with this optional relief valve is piped to a separate storage
vessel, the storage vessel MUST have a properly installed
temperature and pressure relief valve which complies with
local codes.
Installation & Service Manual
Thermal expansion
A relief valve which discharges periodically may be due to
thermal expansion in a closed system. A hot water supply
boiler installed in a closed system, such as one with a
backflow preventer or check valve installed in the cold
water supply, shall be provided with means to control
expansion. Contact the water supplier or local plumbing
inspector on how to correct this situation. Do not plug or
cap the relief valve discharge!
Cathodic protection
Hydrogen gas, which is extremely flammable, can be
produced in a hot water system that has been unused for
a long period of time (generally two weeks or more). To
prevent the possibility of injury under these conditions,
open the kitchen sink hot water faucet for several minutes
before using any electrical appliance connected to the
hot water system. If hydrogen is present, there will be an
unusual sound such as air escaping through the pipe as the
hot water begins to flow. Do not smoke or have open flames
near the faucet at this time.
56
Page 57
8 Maintenance
Installation & Service Manual
Listed below are items that must be checked to ensure safe,
reliable operations. Verify proper installation after servicing.
CAUTION
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation.
Appliance area
Keep appliance area clear and free from combustible materials,
gasoline and other flammable vapors and liquids.
Water circulating pump
Inspect pump every six months and oil as necessary. Use SAE 30
non-detergent oil or lubricant specified by pump manufacturer.
Burner flames
Visually check main burner flames at each start up after long
shutdown periods or at least every six months. Burner viewports
are located on the right and left sides of the unit.
Figure 8-1_Flame patterns
WARNING: The area around the burners is hot and direct contact could result in burns!
NORMAL
A
C
YELLOW FLAME
WARNING
The areas around the burner viewports
are hot. Direct contact with the unit could
result in burns.
Normal Flame: A normal flame is blue with slight yellow tips,
has a well-defined inner cone, and displays no lifting flames.
Yellow Tips: The usual causes for yellow tips on the burner
flame are burner air flow blockage or partial obstruction.
Yellow Flames: The usual causes for yellow flames are primary
air flow blockage to the burner(s) or excessive gas input. Correct
this condition immediately.
YELLOW TIP
B
D
FLAME LIFT
Flue gas passageways cleaning procedure
Any sign of soot around the outer jacket, at the burners or in the
areas between the fins on the copper heat exchanger indicates
a need for cleaning. The following cleaning procedures must
only be performed by a qualified serviceman or installer. Proper
service is required to maintain safe operation. Properly installed
and adjusted units seldom need flue cleaning.
NOTICE
All gaskets on disassembled components must
be replaced with new gaskets on reassembly.
Gasket kits are available from your distributor.
Burner removal and cleaning
1. Turn off main power to unit.
2. Turn off main manual gas shutoff to unit.
3. Remove the front outer jacket panels.
4. Disconnect manifold from gas train using union(s) just
below each gas valve(s).
5. Remove mounting screws from manifold mounting
brackets. Pull the manifold/orifice assembly away from
burners. Repeat for each manifold assembly.
6. Remove two mounting screws from burner and slide
burner out toward front of unit. Use caution to prevent
damage to burners, refractory, hot surface igniter or wiring.
7. Remove soot from burners with a stiff bristle brush.
Dirt may be removed from burner ports by rinsing the
burner thoroughly with water. Drain and dry burners
before re-installing. Damaged burners must be replaced.
When installed in a dusty and dirty location, the burners may
require cleaning on a 3 to 6 month schedule or as needed, based
on severity of contamination. Contaminants can be drawn in
with the combustion air. Non combustible particulate matter
such as dust, dirt, concrete dust or dry wall dust can block
burner ports and cause non-warrantable failure. The standard
inlet air filter will help eliminate dust and dirt from entering
the unit. Use extreme care when operating a unit for temporary
heat during new construction. The burners could require a
thorough cleaning before the unit is placed in service.
Lifting Flames: The usual causes for lifting flames are over firing
the burner(s), excessive primary air, or high draft.
If you observe improper flame patterns, examine the venting
system, ensure proper gas supply, and ensure adequate supply
of combustion and ventilation air.
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Heat exchanger cleaning
1. While burners are removed, check the heat exchanger
surface for sooting. If present, heat exchanger must be
cleaned and problem corrected. Proceed as follows.
2. Remove gas manifold(s)/orifice assemblies as described
in steps 1 through 5 in Burner Removal and Cleaning,
page 57.
3. Disconnect wiring from the hot surface igniter and
hose from the burner pressure tap.
4. Remove inner jacket panel mounting screws and slide
door assembly out toward front of the unit. Use
caution to prevent damage to the refractory and hot
surface igniter.
5. Check “V” baffles and frame runners along front
and back edges of heat exchanger. Remove and clean if
necessary.
6. Remove soot from heat exchanger with a stiff bristle
brush. Use a vacuum to remove loose soot from
surfaces and inner chamber.
7. The heat exchanger can be removed by sliding towards
the front of the unit. Once the heat exchanger is
removed from the unit, a garden hose can be used
to wash the tubes to ensure that all soot is removed
from the heat exchanger surfaces. Note: Do not wet the
unit’s refractory.
8. Ensure that all burner ports are cleaned to remove any
soot. See Burner Removal and Cleaning, page 57.
9. Carefully reinstall the heat exchanger, “V” baffles, and
frame runners if removed from the unit. Note: Make
sure frame runners seal securely where they contact the
front and rear compartment refractory.
10. Carefully reinstall inner jacket panels, burners,
manifolds, wires and hoses. Use new gasket material to
ensure a proper air seal.
11. Reassemble all gas and water piping. Test for gas leaks.
12. Reassemble outer jacket panels.
13. Cycle unit and check for proper operation.
Electrical
This unit uses a transformer to supply a low voltage control
circuit. The voltage on the secondary side should be 24 to
28VAC when measured with a volt meter. Larger models
have a 7AMP circuit breaker provided on the secondary
side of the transformer. A tripped circuit breaker indicates
a short in the 24VAC controls that must be corrected.
Combustion and ventilation air
Combustion air filter
See Combustion Air Filter, page 13.
Air flow
Check frequently to be sure the flow of combustion and
ventilation air to the unit is not obstructed.
Combustion air fan
These units use a fan-assisted combustion process. These units
have one fan to supply combustion air to the burners.
Fan cleaning
Check combustion air fan every six months. Clean fan as
required only when installed in a dusty or dirty location. Oiling
is not required.
Combustion air fan adjustment
The combustion air fan is factory preset and should not need
adjustment in most cases. Follow the steps below to adjust the
fan if a continuous Low Air Status Code occurs.
Check for proper installation and draft in the venting system.
Correct as required.
Adjusting air pressure
The following is a recommended method for setting the air
pressure for the fan.
Setup procedure
To the left of the fan is an air pressure switch with a large and
small tube delivering pressure from points inside the unit
(see FIG. 8-2). The pressure in the large tube is the chamber
pressure. By disconnecting the cap from the tee in the hose and
connecting it to the "(+)" side of a manometer, you can read the
air chamber pressure.
Upon a call for heat, the fan will run for about 90 seconds
before going into soft lockout. If necessary, turn the power to
the unit OFF and then back ON again to recycle the fan.
Note: If the unit has been firing recently, allow the unit to
cool for five minutes with the fan running before
beginning the adjustment procedure.
Note: Retain the plastic cap removed from the tee for
reinstallation when complete.
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Figure 8-2_Air pressure switch
AIR PRESSURE SWITCH
Adjustment procedure Models 497 - 1257:
1. Remove the upper front jacket panels from the unit to
access the upper chamber.
2. Locate the air shutter on the side of the fan housing
(see FIG. 8-3). Turn the adjustment screw on the air
shutter to open or close the shutter. Increase air shutter
opening to increase air pressure. Decrease air shutter
opening to decrease air pressure.
4. Adjust the air shutter until the air chamber pressure is
nominally 1.35 - 1.45 inches water column. See FIG. 8-4
for installations up to 2000 feet altitude. Contact the
factory for high altitude settings.
5. Once the adjustment procedure is complete, reattach the
cap to the tee in the hose and check all tubing and wire
connections for a snug fit. Test fire the unit. Reinstall upper
panels.
Figure 8-3_Adjusting air shutter
TURN THE ADJUSTMENT
SCREW ON THE AIR
SHUTTER TO OPEN OR
CLOSE THE SHUTTER
3. Adjust the air shutter until the air chamber pressure is
nominally 1.25 - 1.30 inches water column for Models
497 - 747 and 1.35 - 1.45 inches water column for Models
987 - 1257. See FIG. 8-4 on installations up to 2000 feet
altitude. Contact the factory for high altitude pressure
settings.
4. Once the adjustment procedure is complete, reconnect
the cap to the tee in the hose and check all tubing and wire
connections for a snug fit. Test fire the unit. Reinstall upper
panels.
Adjustment procedure: Models 1437, 1797 and 2067
1. Remove the upper front jacket panels from the unit to
access the upper chamber.
2. Slightly loosen the screws that attach the fan transition box
to the metal base (see FIG. 8-5).
3. Locate the air shutter at the rear of the fan duct (see
FIG. 8-6). Move the air shutter towards the rear of the
unit to increase air pressure. Move the air shutter towards
the front of the unit to decrease air pressure.
Figure 8-4_Combustion air adjustment with manometer
to set differential pressures
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8 Maintenance
A
Installation & Service Manual
Figure 8-5_Loosening the transition box screws,
Models 1437, 1797 and 2067 only
TRANSITION BOX SCREWS
Figure 8-6_Adjusting the air shutter
DECREASE
IR PRESSURE
INCREASE AIR
PRESSURE
Servicing a hot surface igniter and
ignition module
Ignition system checkout
1. Turn off gas supply to unit.
2. Turn electric power on.
3. Adjust the set point on the temperature control to a
setting above water temperature or to the highest safe
setting.
4. The igniter will cycle on trial for ignition.
5. The ignition module will lock out and turn the alarm
light on.
6. Adjust the Set Point Differential and High-Fire Offset to
the desired settings.
7. Turn on gas supply.
8. Press the module reset button to reset the ignition
module. This is a red button beside the ignition module
or on the diagnostic panel on the header-end of the unit.
9. If ignition system fails to operate properly, repair work
must be performed by a qualified service person or
installer.
Sequence of operation
Overview
This sequence of operation can be considered the order of
events in sequential order that occur after the appliance has
received a call for heat. The process begins with 120VAC
power entering the appliance and ends with the appliance
going into an idle state after completion of a successful call
for heat.
Note: The following descriptions do not include
remotely connected devices that may be
connected to the appliance. Refer to the wiring
diagram for actual point to point wiring
connections that show power delivery.
1. The POWER switch is placed in the “ON” position.
This unit uses a proven hot surface ignition module and a
hot surface igniter. The hot surface ignition module is not
repairable. Any modification or repairs will invalidate the
warranty.
WARNING
A faulty hot surface igniter or ignition module must be
replaced with an identical part. A specification igniter
and ignition module for this specific unit is available from
your local distributor. Do not use general purpose field
replacement ignition modules or igniters.
Do not attempt to repair a faulty hot
surface igniter or ignition module. Any
modification or repairs may create
hazardous conditions that result in
property damage, personal injury, fire,
explosion and/or toxic gases.
2. 120VAC power is supplied to the control transformer along
with L1 and F1 on the ignition module.
3. 24VAC is supplied to the electronic temperature control,
the ignition module and the adjustable high limit control.
4. 24VAC is then supplied to the auxiliary limit control
(if equipped).
5. If equipped, 24VAC is supplied to a low water cut-off and
then to the high and low gas pressure switches.
6. 24VAC is supplied to the continuous alarm terminals A1
and A2 and then to the remote stage one terminal strip,
1C and 1NO.
7. 24VAC is supplied to the electronic temperature control.
8. The electronic temperature control then calls for heat.
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8 Maintenance (continued)
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9. 24VAC is supplied to the intermittent alarm field safety
contacts, B1 and B2.
10. 24VAC is supplied to the water flow switch.
11. 24VAC is supplied to the TH terminals on the ignition
module.
12. As power is applied to the TH terminals on the ignition
module, 120VAC is switched from the F2 terminal to start
the combustion air fan at full speed on Models 497 - 747
and at low speed on Models 987 - 2067.
13. 24VAC is supplied to the C terminal of the air pressure
switch. As the low air switch makes, power is supplied to
the ignition module.
14. 24VAC is then supplied to the PS terminals on the ignition
module as the air pressure switch makes to prove fan
operation.
15. The combustion air fan operates for the pre-purge period.
16. At the end of the pre-purge, 120VAC is applied to the hot
surface igniter and the trial for ignition light.
17. The hot surface igniter proves 1800°F (982°C) ignition
temperature by current draw through the ignition module.
Heat transfer process
28. Heated products of combustion pass over the heat
exchanger transferring heat to the water.
29. The rate of flue product movement is controlled
by “V” baffles on the heat exchanger to maximize heat
transfer.
30. Flue products pass into the flue collector and are
exhausted from the unit.
End of sequence
31. Set point for the high fire on the electronic temperature
control is satisfied.
32. Power to all valves is turned OFF on F9 systems and
power to the high fire gas valves is turned OFF on M9
systems.
33. The water temperature continues to rise and the set
point for low fire is satisfied (M9).
34. Power to the low fire gas valves is turned OFF (M9).
35. The combustion air fan runs for a 30 second post
purge timing and turns OFF.
18. The ignition module supplies voltage to the MV terminals
on to the gas valve(s).
19. The first stage gas valve(s) opens and supplies gas to the
orifice and burner inlet to pre-mix.
20. The gas/air mixture is forced into the burner and out of the
burner ports under pressure.
21. The hot surface igniter lights the gas/air mixture and
then serves as a flame sensor to prove main burner flame by
rectification.
22. Burners are now firing for approximately 50% of the
heater’s input.
23. 24VAC is supplied from the second stage of the electronic
temperature control across the 2C and 2NO terminals on
the terminal strip on to a control to a relay.
24. The control relay switches the fan on Models 987 2067 to high speed and energizes the gas valves for the
remaining 50% of burner input.
25. The remaining gas valves open and supply gas to the
orifice inlet to pre-mix.
36. The appliance is now in a Standby Mode waiting for
the next “call for heat”.
26. The gas/air mixture is forced out of the burner ports
and light by carryover from the burners currently
firing.
27. The heater is now firing at full rated input.
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Power Supply
(AC120VAC/60Hz)
120VAC/60Hz/1PH power connects to black (line) and white
(neutral) wires located within an electrical wiring box located
on the left side of the unit. A green chassis grounding wire is also
provided for connection to earth ground.
ON/OFF Rocker Switch
The black line voltage wire runs directly to a single pole, single
throw On/Off rocker switch located behind the front cover
accessible by a thumb screw. Turning ON the rocker switch
delivers line voltage to the low voltage transformer and ignition
module.
Note: The On/Off switch does not provide for disconnection
of power being supplied to any remotely connected
devices that may be connected to the unit (i.e. pumps,
louvers, power venters, etc.,). As such, it may be
necessary to locate and turn off power to these items
before attempting to service the unit.
Low Voltage Supply Transformer
A 120VAC to 24VAC transformer located within the control
panel provides 24VAC/60Hz to many of the components located
on the unit. One of its 24VAC outputs (blue) is connected to a
circuit breaker and the other (yellow) is connected to chassis
ground.
24VAC Circuit Breaker
A circuit breaker is provided on Models 987 - 2067 for
protection of the low voltage supply transformer from overloads
and short circuits. The breaker is located inside the unit on the
lower right corner of the control panel. Power from this breaker
goes to the electronic temperature controller, ignition module
and various other components and/or options on the unit.
When tripped, all factory-installed 24VAC components will lose
their 24VAC power.
Manual Reset High-Limit Thermostat
A manual reset high limit thermostat is provided as backup for
the temperature controller. This will be an adjustable dial bulbcapillary style thermostat that will trip and require resetting
should water temperature exceed its settings. When tripped, all
controls remain powered, but 24VAC is prevented from being
delivered to the ignition module’s thermostat input.
EMS/Sequencer/Remote Aquastat Terminals
The EMS/sequencer/remote aquastat terminals are provided
for connection of the unit to an external energy management
system or sequencer and are located along the top edge of
the terminal strip located within the electrical wiring box.
In addition to providing a means to externally stage fire the
unit, these terminals also provide for remote shutdown and
override by routing through dry contacts from external devices.
Connection of the external dry contacts to these terminals
requires the removal of one or more factory installed jumpers
located on the terminal strip.
Safety Device Terminals
The safety device terminals ensure that no power can be
delivered to the ignition module unless factory/field-installed
safety devices such as flow switches and gas pressure switches
are closed. These safety device terminals are located below the
EMS/Sequencer/Remote Aquastat terminals located within the
electrical wiring box. Two types of connections are offered:
Continuous terminals provide for connection of safety devices
that are desired to be constantly monitored. Intermittent
terminals are provided for devices that are only monitored
during a “call for heat” cycle. Connection to either of these
terminals requires the removal of a factory-installed jumper
located on the terminal strip.
Electronic Temperature Controller (Operator)
A 2-stage electronic temperature controller is provided on the
unit and it serves to maintain a user selectable temperature set
point. Ultimately, the temperature controller delivers 24VAC
to the ignition module and pressure switch when it senses heat
mode is desired. It also activates the pump relay. If more heat is
needed, it activates the high fire stage.
Ignition Module
(Controlled by Electronic Temperature Controller)
One ignition module is provided on the unit. Upon sensing the
24VAC delivered to it by the electronic temperature controller,
the ignition module checks for a shorted pressure switch and
then, provided the air switch isn’t shorted, supplies 120VAC to
its blower output relay and waits for a pressure switch signal.
Two Speed Blower
(Controlled by Ignition Module and Relay Board)
A single 2-speed blower on Models 987 - 2067 (single 1-speed
blower on Models 497 - 747) provide combustion air to the
unit. The blower is provided with a high and low speed tap.
The blower operates in tandem with the ignition module when
a call for heat signal is received. Depending upon the number of
stages in operation, the blower’s speed may increase or decrease
accordingly.
Pressure Switch
(Activated by Blower Turning On)
One pressure switch is provided to monitor the blower On/
Off operation. Upon a call for heat, 24VAC is delivered to the
pressure switch. If the blower generates adequate air pressure,
the pressure switch closes to deliver 24VAC to the ignition
module pressure switch monitoring input terminal.
Prepurge
(Ignition Module Function)
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9 Glossary (continued)
Installation & Service Manual
Once the ignition module sees a 24VAC input from the
pressure switch, it runs the blower for approximately 15
seconds in order to purge the combustion chamber of any
unburned fuel/air mixture.
Trial for Ignition
(Ignition Module Function)
Once the ignition module has completed its prepurge
period, it turns on the hot surface igniter. Once the
hot surface igniter’s current draw reaches a proper level,
the ignition module begins a trial for ignition period of
approximately 25 seconds to allow time for the igniter to
reach the ignition temperature necessary to ignite the fuel/
air mixture.
Igniter
(Controlled by Ignition Module)
One igniter is provided in order to ignite the fuel/air
mixture and its on/off operation is controlled by the
ignition module.
Hi-Lo Fire Relay
The relay serves as means to switch from low fire to high
fire. On Models 987 - 2067, in addition to switching
between high fire to low fire, the relay also changes the fan
speed from high for high fire to low for low fire.
Post-Purge
(Ignition Module Function)
When 24VAC is removed from the ignition module’s thermostat
input, the module turns off the gas valves and maintains
the blower for approximately 25 seconds in order to allow
the combustion chamber to be purged of all combustion
by-products.
Pump Delay
(Electronic Thermostat Function)
When the electronic thermostat removes 24VAC from the
ignition module, it continues to hold the pump relay on
for 30 seconds in order to get the remaining heat out of the
combustion chamber. The pump then turns off to prevent the
heat in the water from going back into the combustion chamber
and up the flue.
Idle
(Electronic Thermostat Function)
After completion of the post-purge cycle, the unit will go into
an idle state whereby the electronic thermostat continuously
monitors the water temperature until the water temperature
drops to levels that require additional heat.
Ignition
(Ignition Module Function)
Once the trial for ignition period has been completed, the
ignition module sends 24VAC to the gas valves on the low
fire stage (Stage 1). Gas valves should open and allow gas
to flow to the burners in Stage 1 being energized. The fuel/
air mixture should ignite from the hot surface igniter. Once
this voltage has been sent to the valves, the hot surface
igniter is turned off. The ignition module then monitors the
status of the flame and will either allow ignition to continue
or shut down the gas valves should flame not be proven and
proceed to a Flame Failure condition. If flame was proven
briefly during the ignition period, the module may not
proceed to Flame Failure, but rather post-purge and then
go into another trial for ignition.
Heat Transfer Process
(Gas Valves, Burner, and Heat Exchanger)
Once flame has been proven, the ignition module will hold
the gas valves open as long as there is proof of flame and a
call for heat is present. If the low fire stage cannot provide
enough heat to raise the system temperature, the electronic
temperature controller turns on the high fire stage. The high
fire stage will operate until the system water temperature
shows a gain that can be handled by low fire operation.
The high fire stage shuts off at this point. When the lowfire stage alone produces more heat than is required, the
electronic temperature controller turns off the call for heat.
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10 Diagrams
Ladder diagram
Installation & Service Manual
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10 Diagrams (continued)
Ladder diagram (continued)
Installation & Service Manual
0987-2067
0497-747
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10 Diagrams
Connection diagram
Installation & Service Manual
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10 Diagrams (continued)
Connection diagram (continued)
Installation & Service Manual
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Revision Notes: Revision A (ECO #C07390) initial release.
CBX-CWX-I-S Rev A
3/11
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