Lennox GCWB95F-150 User guide

PRODUCT LITERATURE
Lennox Industries Inc.
Dallas, Texas
This manual has been prepared for use with the appropriate Installation, Operation and
Maintenance Manual.
APPLICATION
GUIDE
FOR USE WITH
COMBI
GCWB95F-150
CONDENSING
GAS BOILER
240013003 REV A [04/15/2020]

2
TABLE OF CONTENTS
Important Safety Information........................................................................................ 3
Labor Saving Piping Manifold / Near Boiler Piping Connections.. ...................................4
General Information - Hydronic Piping...........................................................................5
General Information - Wiring ......................................................................................... 7
Piping And Wiring Diagrams
Piping Legend...................................................................................................................8
GCWB9F-150 With Zone Circulator Pumps - Piping Diagram................................................9
GCWB9F-150 With Zone Pumps - Wiring Diagram...........................................................10
GCWB9F-150 With Zone Pumps ...................................................................................11
GCWB9F-150 With Zone Valves - Piping Diagram.............................................................12
LBuer Tank - Piping and Wiring Diagram.................................................................... 13
Optional Equipment...................................................................................................... 14
Outdoor Air Sensor Data .......................................................................................14
Wiring Diagrams
GCWB9F-150 Floor Standing - Combi Wiring Diagram..........................................................15
Altitude Eects On Boiler Performance......................................................................... 16
Low Water Cuto Application ....................................................................................... 17
Error Code Table........................................................................................................... 22
Troubleshooting Chart.................................................................................................. 23
Fault Solution Sections................................................................................................. 25
PN 240013003 REV. A [04/15/2020]

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IMPORTANT SAFETY INFORMATION
CAUTION
Indicates a hazardous situation which, if not
avoided, could result in minor or moderate injury.
!!
WARNING
Indicates a hazardous situation which, if not
avoided, could result in death or serious injury.
!
DANGER
Indicates a hazardous situation which, if not
avoided, WILL result in death or serious injury.
!
This is the safety alert symbol. Symbol alerts you toThis is the safety alert symbol. Symbol alerts you to
potential personal injury hazards. Obey all safety messagespotential personal injury hazards. Obey all safety messages
following this symbol to avoid possible injury or death.following this symbol to avoid possible injury or death.
2.2. Become familiar with symbols identifyingBecome familiar with symbols identifying
potential hazards.potential hazards.
1. General
Boiler installation shall be completed by qualified agency.
See Installation, Operation & Maintenance Manual for
additional information.
WARNING
Fire, explosion, asphyxiation and electrical shock
hazard. Improper installation could result in death
or serious injury. Read this manual and understand
all requirements before beginning installation.
!
3. Installation shall conform to requirements of
authority having jurisdiction or in absence of such
requirements:
• United States
• National Fuel Gas Code, ANSI Z223.1/NFPA 54 .
• National Electrical Code, NFPA 70.
• Canada
• Natural Gas and Propane Installation Code, CAN/
CSA B149.1.
• Canadian Electrical Code, Part I, Safety Standard for
Electrical Installations, CSA C22.1
4. Where required by authority having jurisdiction,
installation shall conform to Standard for Controls
and Safety Devices for Automatically Fired Boilers,
ANSI/ASME CSD-1.
Additional manual reset low water cutoff and/or high limit
may be required.
5. Requirements for Commonwealth of
Massachusetts:
Boiler installation must conform to Commonwealth of
Massachusetts code 248 CMR which includes but is not
limited to:
• Installation by licensed plumber or gas fitter.
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4
NEAR BOILER PIPING CONNECTIONS
GCWB95F-150 COMBI
LEGEND 150
AHeating supply connection

BDHW outlet 1/2" sweat
CDrain connection for condensate
3/4" NPT
D 3/4" NPT
ECold DHW inlet tap 1/2" sweat
FHeating return connection

A
B
A
E
A
A
A
C
A
D
A
F
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GENERAL INFORMATION - HYDRONIC PIPING
General Information:
Piping installation, materials, and joining methods shall
conform to requirements of authority having jurisdiction or
in absence of such requirements:
• USA - National Fuel Gas Code, ANSI Z223.1/NFPA 54
• Canada - Natural Gas and Propane Installation Code,
CAN/CSA B149.1
Manufacturer Requirements/Recommendations:
• Manufacturer requires all domestic hot water
(DHW) installations use an anti-scald valve.
Local codes may require additional equipment
(expansion tank, relief valves, etc.) Select and
size equipment to suit installation and meet code
requirements.
• Manufacturer recommends use of a water filter on
incoming water supply line.
• Manufacturer recommends use of a magnetic dirt
separator in the hydronic system where there are
cast iron or steel components, or where the previous
boiler was a cast iron heat exchanger. The abrasive,
extremely fine sediment is difficult to remove and can
deposit onto heat exchanger surfaces and accumulate
in pump cavities causing reduced efficiency and
premature wear.
• The ASME temperature and pressure relief valve and
temperature and pressure gauge shall be installed
to conform to requirements of the authority having
jurisdiction. Refer to appropriate manufacturer
instructions for installation requirements.
• If piping manifold is not used, a primary/secondary
piping arrangement is manufacturer required.

return pipe (closely spaced tees) of the boiler shall be
maintained.
• Limit combined supply and return pipe lengths to
maximum linear lengths of 20 ft (6.1 m) between
boiler and closely spaced tees, when minimum

increased if supply and return pipe size is increased
to limit pressure drop.
• Manufacturer recommends installing a shutoff
and purge valve to use during commissioning to
ensure the boiler does not shut down due to over
temperature. Do not install shutoff between boiler
and LWCO.
WARNING
Burn and scald hazard! Manufacturer requires
installation of field supplied anti-scald valve.
Failure to follow these instructions could result in
death or serious injury.
!FOR YOUR SAFETY READ BEFORE OPERATING
Hot Water Can Scald!
Water heated to temperature for clothes
washing, dish washing and other sanitizing
needs can scald and cause permanent injury.
Children, elderly, and infirm or physically
handicapped persons are more likely to be
permanently injured by hot water. Never leave
them unattended in bathtub or shower. Never
allow small children to use a hot water tap or
draw their own bath.
If anyone using hot water in the building fits the
above description, or if state laws or local codes
require certain water temperatures at hot water
taps, you must take special precautions:
• Use lowest possible temperature setting.
• Install some type of tempering device, such
as an automatic mixing valve, at hot water
tap or water heater. Automatic mixing valve
must be selected and installed according
to manufacturer's recommendations and
instructions.
• Water passing out of drain valves may be
extremely hot. To avoid injury:
• Make sure all connections are tight.
• Direct water flow away from any person.
DANGER
!
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Note Provided Wiring and Piping illustrations
are meant to show system concepts only.
Installer is responsible for all equipment
required by authority having jurisdiction.
Note Arrange piping to prevent water dripping
onto boiler.
GENERAL INFORMATION - HYDRONIC PIPING
Water
Temperature
Seng
1st Degree Burn
Exposure Time For
An Adult
2nd and 3rd Degree Burn
Exposure Time For An
Adult
120° F 1 minute 5 minutes
130° F 5 seconds 30 seconds
140° F 2 seconds 5 seconds
150° F 1 second 1.5 seconds
160° F Instantaneous 0.5 seconds
Note: Warning for Infants, Children, and Elderly:
Great care must be taken when exposing the
aforementioned groups to warm or hot water as they
can be badly burned in exposure times less than half
of the time for an adult.
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GENERAL INFORMATION - WIRING
Electical Wiring Information:
All field wiring shall conform to the authority having
jurisdiction or, in the absence of such requirements to:
• USA: National Electrical Code, ANSI/NFPA 70,
• Canada: Canadian Electrical Code, Part I, CSA
C22.1: Safety Standard for Electrical Installations.
Wiring diagrams shown in this manual utilize the ARGO™
Universal Control, and optional use of a H2O Buffer Tank.
Note DO NOT use 120 V thermostat
terminals (m1- #1 and #2).
Provided Wiring and Piping illustrations
are meant to show system concepts only.
Installer is responsible for all equipment
required by authority having jurisdiction.
Note
SUPPLY Cord
120V/60HZ
BOILER CONTROL
1K Ω
Outdoor
Reset
Sensor
Zone Control
End-Switch
Open Therm 0-10 V Connection
*
* Ground Sensors using terminal 4
G
Do Not
Use
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PIPING LEGEND
ZONE VALVE
BALL VALVE
AIR SEPARATOR
CIRCULATOR
DRAIN
COMBINATION FILL
FLOW CHECK VALVE
BYPASS VALVE
DIVERTER VALVE
T&P OR RELIEF VALVE
THERMOSTATIC MIXING VALVE
TEMPERATURE & PRESSURE GAUGE
EXPANSIONTANK
FLAT PLATE HEAT EXCHANGER
(COMBI ONLY)
STRAINER
PIPING LEGEND
PURGE VALVE
MAGNETIC DIRT SEPARATOR
PN 240013003 REV. A [04/15/2020]

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GCWB95F-150 WITH ZONE CIRCULATOR PUMPS
GCWB95F-150 WITH ZONE CIRCULATOR PUMPS - PIPING DIAGRAM
MAGNETIC DIRT SEPARATOR
PN 240013003 REV. A [04/15/2020]

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GCWB95F-150- WITH ZONE PUMPS - WIRING DIAGRAM
GCWB95F-150 WITH ZONE PUMPS
PN 240013003 REV. A [04/15/2020]

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GCWB95F-150 WITH ZONE VALVES
GCWB95F-150 WITH ZONE VALVES - PIPING DIAGRAM
MAGNETIC DIRT SEPARATOR
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GCWB95F-150 WITH ZONE VALVES - WIRING DIAGRAM
GCWB95F-150 WITH ZONE VALVES
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LOW MASS - PIPING DIAGRAM
Buffer Tank Piping
When installing low mass systems, additional water mass
may be required to avoid short cycling by the boiler. In
these applications it is recommended that a buffer tank be
installed.
Note:
• DHW piping not shown for clarity. Reference applicable sections of this
manual for DHW piping details.
• Internal Boiler circulator used on Primary circuit.
• Reference Buffer Tank Installation Manual for proper sizing and installation.
Buffer Tank on Central Heat Circuit
H2O Stainless
Steel Buffer
Tank
MAGNETIC DIRT
SEPARATOR
PURGE VALVE
PN 240013003 REV. A [04/15/2020]

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OPTIONAL EQUIPMENT
Optional Equipment
IMPORTANT: Sensors supplied with this boiler are proprietary to the manufacturer. Use of alternate market sensors
WILL diminish boiler performance.
1. 1k Ω Outdoor Air Sensor, if used.
A. Boiler automatically recognizes sensor when used.
B. See Chart 1 for sensor data. Sensor part number BD710487302V
C. Locate outdoor sensor to protect against wind and direct sunlight. Mounting instructions provided with sensor.
D. Maximum wire length is 100 ft (30m) for 22 ga. wire, or 150 ft (45m) for 18 ga. wire.
E. Connect wires to M2 OUTDOOR SENSOR terminals 4 & 5. Wires are interchangeable. See Accessories.
CHART 1 -1k Ω OUTDOOR AIR SENSOR DATA
T R T R
[°F] [Ohm] [°F] [Ohm]
-4.0 7,578 53.6 1,690
-2.2 7,193 55.4 1,621
-0.4 6,831 57.2 1,555
1.4 6,489 59.0 1,492
3.2 6,166 60.8 1,433
5.0 5,861 62.6 1,375
6.8 5,574 64.4 1,321
8.6 5,303 66.2 1,268
10.4 5,046 68.0 1,218
12.2 4,804 69.8 1,170
14.0 4,574 71.6 1,125F
15.8 4,358 73.4 1,081
17.6 4,152 75.2 1,040
19.4 3,958 77.0 1,000
21.2 3,774 78.8 962
23.0 3,600 80.6 926
24.8 3,435 82.4 892
26.6 3,279 84.2 858
28.4 3,131 86.0 827
30.2 2,990 87.8 796
32.0 2,857 89.6 767
33.8 2,730 91.4 740
35.6 2,610 93.2 713
37.4 2,496 95.0 687
39.2 2,387 96.8 663
41.0 2,284 98.6 640
42.8 2,186 100.4 617
44.6 2,093 102.2 595
46.4 2,004 100.4 617
48.2 1,920 102.2 595
50.0 1,840 104.0 575
51.8 1,763 106.0 556
PN 240013003 REV. A [04/15/2020]

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Accessories:
ACCESSORIES
1. 1k Ω Outdoor Temperature Sensor Kit - BD710487302V
Use Outdoor Sensor Kit with Heating Only or Combi Boilers.
Wire Control to boiler M2 terminal strip terminals #4 and #5
as shown below.
Install/locate Control according to instructions supplied
with sensor kit and Installation, Operation and Maintenance
Manual (IOM).
Setting “Kt
Start boiler in CH mode. Depress CH control button once.
Boiler control will recognize installed OAS sensor. Display
will change to show current default “Kt” value. Note display
value.
When operation in CH mode, Kt value setting will over
ride maximum CH boiler control set point based on current
outdoor temperature.
• Refer to applicable °F (or °C) chart,
• Identify Kt range that will satisfy the desired boiler
delivery temperature based on average (extreme)
outdoor temperature range expected for climate location.
Flow Temp Outside Temp
Boiler Control Panel
Note For temperatures below -40°F (-40°C), maximum heating flow temperature set point no longer
increases and curves on the graph become horizontal. Boiler set point will override sensor
setpoint.
°F°C
• Use lower value of range as the desired Kt value.
(Example): to deliver 186°F water @ OT of -20°F = Kt range is 90 thru
25. Select 25.
• Kt value on boiler control use +/- CH
Heating buttons.

value as new Kt default value and automatically return to CH
mode when no Kt adjustment activity is sensed. Kt values can
be changed in +/- 1 point increments.
To return to check or change current Kt “default value -
depress one of the CH set-point adjustment buttons (once),
while in any heating or standby mode. Adjust Kt value to
obtain desired comfort level.
80 Is Default.
1k Ω
PN 240013003 REV. A [04/15/2020]

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ACCESSORIES
Management of 0-10V Input
The functions with 0...10V regulator are activated by means of their parameters. When the function is enabled
(P82=3) and P78=1, the input manages the heating set point temperature directly; when P78=2, the input
manages the heating power input directly. Demand is activated above 3V and the heating setpoint is calculated in
proportion to deviation from 3 to 10 V DC, to give a setpoint that goes from minimum to maximum.
GCWB95F-150
0-10V DC Electrical Signal Input P78=1 P78 = 2
Heating Flow Setpoint Temperature Central Heating - Heat Input (Gross)
(V) (°F) (°C) (kW) (Btu/h)
0...3 OFF
3 77 25 6.4 22,000
4 95 35 10.8 36,700
5 108 42 15.1 51,400
6 124 51 19.4 66,100
7 140 60 23.7 80,800
8 154 68 28.0 95,500
9 167 75 32.3 110,200
10 176 80 36.6 125,000
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MODEL 150F - Combi
150F FLOOR STANDING - COMBI WIRING DIAGRAM
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ALTITUDE EFFECTS ON BOILER PERFORMANCE
40,000
60,000
80,000
100,000
120,000
140,000
160,000
02,000 4,000 6,000 8,000 10,000
BOILER INPUT (BTUH)
ALTITUDE (FEET)
MODELS 125/150
CALCULATED EFFECTS OF HI-ALTITUDE ON BOILER
PERFORMANCE
DHW MODE
HEAT MODE
NET RATNG
HEAT MODE
60,000
80,000
100,000
120,000
140,000
160,000
180,000
200,000
220,000
02,000 4,000 6,000 8,000 10,000
BOILER INPUT (BTUH)
ALTITUDE (FEET)
MODELS 165/205
CALCULATED EFFECTS OF HI-ALTITUDE ON BOILER
PERFORMANCE
DHW MODE
HEAT MODE
NET RATNG
HEAT MODE
Model GCWB95F-150
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A - LOW WATER CUTOFF
Low Water Cut Off
These guidelines are supplied when necessary to install
an additional Low Water Cut Off (LWCO), for sensing a
low water level condition in a boiler, as required by the
Authority Having Jurisdiction.
Follow LWCO manufacturer installation instructions for
type of LWCO selected in addition to these instructions.
LWCO shall be 120V/60HZ control and dry contacts sized for
load being connected. Wire control to boiler. See Figure 1.
Connect LWCO device to the system ground. Ground in
accordance with the requirements of the authority having
jurisdiction or, in the absence of such requirements, with
the National Electrical Code (NEC) or Canadian Electrical
Code CEC.
LWCO Wiring Diagram
Low Water Cutoff (LWCO)
Electrical Conduit
J-Box
120 V/60 HZ
Conduit or Power
Supply cord
(Polarized)
L1
N
G
GND
L1
N
GND
BLK
WHT
120 V/60 HZ Socket
(Polarized) 120 V/60 HZ
Cord Set From Boiler
N.O
• Locate LWCO sensing device in the supply
piping, above the minimum height of boiler.
See Figure A-2, Piping Diagram.
• Position control in HORIZONTAL piping to assure
proper boiler protection (upright or 90° rotation).
• For proper operation, sensing element of the LWCO
control shall be positioned in the tee to sense the

from pipe walls. Element shall NOT contact the rear,
or side walls of the tee. See Figure A-3.
• Install an air vent using a tee to avoid nuisance
shutdowns.
• Apply small amount of pipe sealant to threaded
connections.
• Arrange piping to prevent water dripping onto boiler.
• DO NOT install water shutoff valve between boiler
and LWCO sensing device.
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Piping Diagram - LWCO Location
LOW WATER CUTOFF
Low Water Cutoff (LWCO)
(See Figure 6-5 for detail)
Air Vent
Supply Safety Relief
Valve
Position LWCO Above
Top of Boiler
1DO NOT PLACE ISOLATION VALVE
BEFORE TEE OR LWCO.
Note
*To
Drain
* Check Local Codes for
Maximum Distance to
Floor.
Arrange piping to prevent
water dripping onto boiler.
1
Return
Purge Valve
Magnetic
Dirt
Separator
Position Temperature/
Pressure Gauge on CH
System Supply Side
of Boiler.
Purge Valve
Note
Illustrations are meant to
show system piping concept
only. Installer is responsible
for all equipment and detailing
required by authority having
jurisdiction.
Note
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