Buderus Logano plus GB312 User manual

For qualified technicians
Please read carefully prior
to installation and mainte-
nance
CAUTION!
Observe the safety instructions of this installation and
maintenance manual before placing the boiler in oper-
ation.
DANGER!
If installation, adjustment, modification, operation or
maintenance of the heating system is carried out by
an unqualified person, this may result in danger to life
and limb or property damage. The directions of this
installation and maintenance manual must be fol-
lowed precisely. Contact a qualified service com-
pany, service provider or the gas company if support
or additional information is required.
CAUTION!
The operating manual is a component of the techni-
cal documentation and must be handed over to the
operator of the heating system. Discuss the instruc-
tion in this manual with the owner or operator of the
heating system to ensure that they are familiar with all
information required for operation of the heating sys-
tem. If the boiler will be installed in Massachusetts, it
must be installed by an installer or dealer who is reg-
istered there.
Installation and servicing
instructions
Gas condensing boiler
Logano plus GB312
7 747 010 719 - 06/2009 US

Contents
Logano plus GB312 - Technical specifications are subject to change without prior notice
2
Contents
1 General safety instructions and explanation of
symbols 4
1.1 Safety instructions 4
1.2 Explanation of symbols 5
2 Details of the product 6
2.1 Intended use 6
2.2 Standards, regulations and directives 6
2.2.1 National regulations 6
2.3 Compliance with standards and regulations 6
2.3.1 Massachusetts installations only 7
2.4 Notes on installation and operation 8
2.4.1 Other important information 8
2.5 Heating system water quality 8
2.6 Tools, materials and equipment 8
2.7 Disposal 8
2.8 Product description 9
2.9 Package contents 11
2.10 Dimensions and specifications 12
2.10.1 Logano plus GB312 dimensions 12
2.10.2 Specifications 13
3 Transporting the boiler 15
3.1 Lifting and carrying the boiler 15
3.2 Transporting the boiler on rollers 17
4 Installing the boiler 18
4.1 Boiler room requirements 18
4.2 Recommended wall clearances 19
4.3 Leveling the boiler 19
5 Openings for combustion air supply
and venting 20
6 Installing the boiler 22
6.1 Connecting the flue pipe to the boiler 24
6.2 Installing the flue system 24
6.3 Installing the wall exit for a horizontal flue 25
6.4 Installation of the roof penetration of a vertical flue
systems 26
6.5 Connecting the air supply (for direct vent operations)26
6.6 Installing the wall exit for the air pipe 27
6.7 Installing the roof exit for the air pipe 27
6.8 Design of flue and air pipe for direct vent operation 28
6.9 Connecting the heating system 29
6.9.1 General safety instructions 29
6.9.2 Connecting the boiler to the heating system 30
6.9.3 Installing B-Kit 30
6.9.4 Connecting the central heating supply 32
6.9.5 Fitting the heating system return 32
6.9.6 Installing the DHW Tank 32
6.9.7 Installing the condensate drain 33
6.10 Filling the heating system and checking for leaks 34
6.11 Connecting the fuel supply 36
6.11.1 Installing gas feed 36
6.11.2 Installation at high altitudes 37
6.12 Electrical connections 38
6.12.1 Connecting the main power supply 38
6.12.2 Leveling the boiler 40
7 Recommissioning the heating system 41
7.1 Checking the operating pressure 42
7.2 Checking for leaks 43
7.3 Checking appliance equipment 43
7.4 Checking the air supply/ventilation and flue pipe
connection 44
7.5 Checking the air inlet diaphragm 44
7.6 Purging the gas pipe 45
7.7 Making the heating system ready for operation 45
7.8 Commissioning the control unit and burner without
programming unit RC35 45
7.9 Commissioning the control unit and burner with
programming unit RC35 45
7.9.1 Boiler intended to be used with Logamatic 4000 45
7.9.2 Boiler intended to be used with RC35 46
7.9.3 Continuing commissioning procedure with RC35 46
7.10 Switching on the boiler on the BC10 46
7.10.1 Conducting a flue gas test 47
7.10.2 Opening the Service menu and viewing monitor
data on the RC35 47
7.11 Adjusting and checking CO2 level
at maximum output 48
7.11.1 CO2 content, natural gas type A 48
7.12 Adjusting and checking CO2 level
at minimum output 48
7.12.1 CO2 content, natural gas type A (minimum output) 49
7.12.2 Reading off and comparing CO2 levels 49
7.13 Checking and monitoring CO2 level
at maximum output 49
7.14 Recording measured values 49
7.14.1 Switching the status display on the BC 10
to show the boiler temperature 50
7.14.2 Returning to operating mode from the flue gas test 50
7.14.3 Flue pressure 50
7.14.4 Carbon monoxide content 50
7.15 Function checks 51
7.15.1 Checking the (flame) ionization current 51
7.16 Measuring the gas supply dynamic pressure 52
7.17 Checking for leaks during operation 52
7.18 Fitting outer casing components 53

Contents
Logano plus GB312 - Technical specifications are subject to change without prior notice 3
7.19 Informing the owner/operator and
handing over technical documentation 53
7.20 Commissioning log 54
8 Shutting down the heating system 55
8.1 Shutting down the heating system using the programmer
55
8.2 Shutting down the heating system in an emergency 55
8.2.1 Action in an emergency 55
9 Heating system servicing 56
9.1 Preparing the boiler for servicing 57
9.2 General operations 57
9.3 Checking the flue system inc. combustion air supply,
inlet and outlet air vents 58
9.4 Checking the heating system operating pressure 58
9.5 Measuring the carbon dioxide content 59
9.6 Determining how dirty the burner and
heat exchanger are and cleaning them 59
9.6.1 Determining the extent of contamination 59
9.6.2 Cleaning the burner and heat exchanger 61
9.7 Checking gas valve for leaks 67
9.8 Checking for leaks during normal operation 69
9.9 Testing ionization current 69
9.10 Concluding servicing/maintenace 69
9.10.1 Removing instruments 69
9.10.2 Fitting outer casing components 69
9.10.3 Confirming servicing/maintenance 69
9.11 Servicing and maintenance logs 70
10 Troubleshooting 72
10.1 Identifying operating modes and resetting faults 72
10.2 Operating and fault messages 73
10.2.1 Operating messages 73
10.2.2 Fault messages 75
10.3 Troubleshooting safety sequence/pressure switch 88
11 Sensor characteristics 91
12 Spare parts 92
13 Boiler internal wiring diagram 116
14 Examples of Installations 117
14.1 Boiler, low-loss header, AM10 117
14.2 Boiler, low-loss header, Logamatic 4000 118
14.3 2 Boilers , low-loss header, Logamatic 4000
with FM 456 Module 119
Index 120

1General safety instructions and explanation of symbols
Logano plus GB312 - Technical specifications are subject to change without prior notice
4
1 General safety instructions and explanation of symbols
1.1 Safety instructions
If you smell gas
VTurn off the gas valve (Æpage 55).
VOpen windows and doors.
VDo not operate any electrical switches or equipment
such as telephones, power plugs and doorbells.
VExtinguish all open flames. Do not smoke. Do not use
lighters of any kind.
VWarn all occupants of the building, but do not ring
doorbells.
VIf you can actually hear gas escaping, leave the building
immediately. Prevent others from entering and notify
the police and fire department from outside the build-
ing.
VFrom outside the building, call gas supplier and
approved heating contractor.
If you smell flue gas
VSwitch "off" the boiler (Æpage 55).
VOpen windows and doors.
VInform an authorized heating contractor.
Risk of poisoning. An insufficient supply of air can
result in dangerous escape of flue gas.
VNever close off or reduce the size of air inlet or outlet
vents.
VThe boiler must not be operated until the obstruction
has been removed.
VInform the system operator in writing of the problem
and associated danger.
Danger from escaping flue gases.
VMake sure that the flue pipes and seals are not dam-
aged.
VUse high temperature silicon as sealing compound.
VThe boiler must not be fitted with a barometric damper
or a thermally controlled flue flap downstream of the
flue socket.
VConnect only one boiler to each flue system or chimney
flue.
VConnection of another boiler may cause serious injury
or death.
VThe flue system piping must not feed into another air
extraction duct.
VDo not route the flue system piping through or inside
another air extraction duct, for example where there is
a masonry or prefabricated chimney flue.
Danger of explosion of flammable gases.
VAny work on components that carry gas may only be
carried out by an approved heating contractor.
Dangers posed by explosive and easily combusti-
ble materials
VDo not use or store easily combustible materials
(paper, lace curtains, clothing, thinners, paints, etc.)
near the boiler.
VMaintain a clearance of 16 inches from the boiler.
Combustion air
VKeep the combustion air free of corrosive substances
(e.g. halogenated hydrocarbons that contain chlorine
or fluorine compounds). In that way you will prevent
corrosion.
Danger from electric current when the boiler is
open.
VBefore opening the boiler: Disconnect the heating sys-
tem from the electrical power supply by means of the
emergency stop switch or the relevant circuit breaker
on the main fuse board.
VIt is not sufficient just to switch off the control unit.
VTake measures to ensure the heating system can not
be switched on again unintentionally.
Danger due to short-circuits
To prevent short circuits, only
Vuse genuine Buderus wiring replacement parts.
Installation and adjustment
VCorrect and proper installation and adjustment of the
burner and the programmer are the fundamental
requirements for safe and economical operation of the
boiler.
VThe boiler may only be installed by an approved heating
contractor.
VDo not modify any parts that carry flue gas.
VWork on gas components may only be carried out by
qualified and authorized personnel.
VOnly qualified electricians are permitted to carry out
electrical work. Installation regulations must be com-
plied with.
VWith balanced flue appliances: do not cover or
reduce the size of ventilation openings in doors, win-
dows and walls. If draft-proof windows are fitted,
ensure there is an adequate supply of air to the room
for combustion.
VNever shut off safety valves. Water may escape
from the safety valve for the hot water system and pip-
ing when the water is being heated.

1
General safety instructions and explanation of symbols
Logano plus GB312 - Technical specifications are subject to change without prior notice 5
Maintenance and servicing
Heating systems should be regularly maintained for the
following reasons:
– to achieve a high level of efficiency and to operate the
system economically (low fuel consumption),
– to achieve a high level of operational reliability,
– to maintain the cleanest possible combustion.
VRecommendation for users: take out a maintenance
and servicing contract with an approved heating con-
tractor covering annual servicing and condition-based
maintenance.
VServicing and repairs may only be carried out by an
approved heating contractor.
VImmediately correct all faults to prevent system dam-
age.
VThe operator is responsible for the general and environ-
mental safety of the heating system.
VUse only genuine spare parts. Damage caused by the
use of parts not supplied by Buderus is not covered by
the Buderus warranty.
Instructing the customer
VExplain to the customer how the boiler works and how
to operate it.
VInform the customer that he/she must not carry out any
alterations or repairs.
1.2 Explanation of symbols
Signal words are used to indicate the seriousness of the
ensuing risk if measures for minimising damage are not
taken.
–Caution indicates that minor damage to property may
occur.
–Warning indicates that minor personal injury or severe
damage to property may occur.
–Danger means that severe personal injury may occur.
Very serious cases may result in death.
Notes contain important additional information.
Notes do not contain any warnings or information about
hazards or risks.
Warnings are indicated by a warning trian-
gle and a grey background.
Notes are identified in the text by this sym-
bol. They are bounded by horizontal lines
above and below the text.

2Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice
6
2 Details of the product
These installation and servicing instructions contain
important information regarding the safe and proper
installation, commissioning and servicing of the Logano
plus GB312 gas condensing boiler.
These installation and servicing instructions are intended
for qualified heating contractors, who – as a result of their
technical training and experience – are skilled in dealing
with heating systems and gas installations.
The boiler can be fitted with a programming unit such as
the RC35 (available separately).
Only use the boiler in the combinations and with the
accessories and components that are specified in the
installation and servicing instructions.
Use other combinations, accessories and consumables
only if they are specifically intended for the proposed
application and they do not affect performance character-
istics and safety requirements.
2.1 Intended use
The Logano plus GB312 is designed for heating central
heating system water and, with the use of an indirect tank,
domestic hot water, for instance in apartment buildings.
2.2 Standards, regulations and direc-
tives
2.2.1 National regulations
The heating system must comply with the requirements of
the relevant regulatory authorities or otherwise of the
National Fuel Gas Code, ANSI Z 223.1. In Canada, the
requirements of CAN/CSA-B.149.1 and 2, Installation
Code for Gas Burning Appliances and Equipment, must
be observed.
If specified by the relevant regulatory authorities, the heat-
ing system must comply with the regulations of the Stan-
dard for Controls and Safety Devices for Automatically
Fired Boilers, ANSI/ASME CSD-1.
Carbon monoxide detectors must be installed as speci-
fied by the local regulations. The boiler must be serviced
annually.
Boiler operating conditions
The heat exchanger has been designed and certified in
accordance with the ASME Boiler and Vessel Code, Sec-
tion IV.
Maximum boiler temperature: 200 °F
Maximum operating pressure: 50 psi
The hot water piping system must comply with the appli-
cable legislation and regulations. If an existing boiler is
replaced, the complete hot water piping system must be
inspected to ensure that it is in perfect condition to ensure
safe operation.
2.3 Compliance with standards and reg-
ulations
The design and mode of operation of this boiler comply
with the American National Standard ANSI Z21.13/
CSA4.9, latest edition for Gas Fired Low Pressure Steam
and Hot Water Boilers.
Other confirmed approvals and certifications are indi-
cated by stickers on the boiler.
Installation of the boiler must comply with all applicable
codes and regulations imposed by the national, Federal or
local authorities and bodies. If no specific requirements
are defined, in the USA, the latest edition of the National
Fuel Gas Code ANSI Z223.1/NFPA 54 must be complied
with. In Canada, installation must comply in all respects
with the latest edition of the Installation Code for Gas
Burning Appliances and Equipment, CAN/CSA-B.149
and the applicable local regulations and requirements for
the appliance category. The relevant authorities and regu-
latory bodies must be informed before installation starts.
Where required by local regulations, the system must
comply with the American Society of Mechanical Engi-
neers Safety Code for Controls and Safety Devices for
Automatically Fired Boilers (ASME CSD-1).
In the Commonwealth of Massachusetts, this appliance
must be installed by a licensed pipe fitter, taps external to
the boiler must be fitted with T-handles and condensate
piping must be fitted in accordance with the State Plumb-
ing Code.
Observe all standards and guidelines appli-
cable to the installation and operation of this
heating system in your country.

2
Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice 7
2.3.1 Massachusetts installations only:
(a) For all side wall horizontally vented gas fueled equip-
ment installed in every dwelling, building or structure used
in whole or in part for residential purposes, including
those owned or operated by the Commonwealth and
where the side wall exhaust vent termination is less than
seven (7) feet above finished grade in the area of the vent-
ing, including but not limited to decks and porches, the
following requirements shall be satisfied:
1. INSTALLATION OF CARBON MONOXIDE DETEC-
TORS.
At the time of installation of the side wall horizontal vented
gas fueled equipment, the installing plumber or gasfitter
shall observe that a hard wired carbon monoxide detector
with an alarm and battery back-up is installed on the floor
level where the gas equipment is to be installed. In addi-
tion, the installing plumber or gasfitter shall observe that a
battery operated or hard wired carbon monoxide detector
with an alarm is installed on each additional level of the
dwelling, building or structure served by the side wall hor-
izontal vented gas fueled equipment. It shall be the
responsibility of the property owner to secure the services
of qualifed licensed professionals for the installation of
hard wired carbon monoxide detectors.
a. In the event that the side wall horizontally vented gas
fueled equipment is installed in a crawl space or an attic,
the hard wired carbon monoxide detector with alarm and
battery back-up may be installed on the next adjacent floor
level.
b. In the event that the requirements of this subdivision
can not be met at the time of completion of installation, the
owner shall have a period of thirty (30) days to comply
with the above requirements; provided, however, that dur-
ing said thirty (30) day period, a battery operated carbon
monoxide detector with an alarm shall be installed.
2. APPROVED CARBON MONOXIDE DETECTORS.
Each carbon monoxide detector as required in accor-
dance with the above provisions shall comply with NFPA
720 and be ANSI/UL 2034 listed and IAS certified.
3. SIGNAGE.
A metal or plastic identification plate shall be permanently
mounted to the exterior of the building at a minimum
height of eight (8) feet above grade directly in line with the
exhaust vent terminal for the horizontally vented gas
fueled heating appliance or equipment. The sign shall
read, in print size no less than one-half (1/2) inch in size,
"GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL
OBSTRUCTIONS".
4. INSPECTION. The state or local gas inspector of the
side wall horizontally vented gas fueled equipment shall
not approve the installation unless, upon inspection, the
inspector observes carbon monoxide detectors and sig-
nage installed in accordance with the provisions of 248
CMR 5.08(2) (a)1 through 4.
– A product-approved vent terminal must be used, and if
applicable, a product-approved air intake must be
used. Installation shall be in strict compliance with the
manufacturer’s instructions. A copy of the installation
instructions shall remain with the boiler or equipment at
the completion of the installation.

2Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice
8
2.4 Notes on installation and operation
When installing and operating the heating system
observe the following:
– The local building regulations regarding the installation
conditions.
– The local building regulations regarding air supply and
venting systems and the chimney flue connection.
– Electrical code requirements for connection to the
power supply.
– The technical regulations of the gas company regard-
ing the connection of the gas burner to the local main
gas supply.
– The regulations and standards relating to the safety
systems for the water heating system.
2.4.1 Other important information
– The installation of a boiler must be notified to and
approved by the relevant gas supplier.
– Only operate the boiler with the combined air/flue sys-
tem specifically designed and approved for it.
– Remember that regional approvals are required for the
flue system and connecting the condensate outlet to
the public sewer system.
2.5 Heating system water quality
As pure water cannot be used for heat transfer,
water quality is important. Poor water quality can
damage heating systems due to scale formation
and corrosion. For further details, please see the
accompanying "Water quality requirements for
Logano plus GB312" manual.
2.6 Tools, materials and equipment
For the installation and maintenance of the boiler, you will
require the standard tools used for central heating and
gas and water systems plus set of a metric wrenches and
hex keys.
The following may also prove useful:
– The RC35 programming unit is required as a monitor-
ing device for commissioning, servicing and maintain-
ing the boiler.
– 2 pipes (approx. 1¼", approx. 6.6 ft long) for carrying
the boiler or 5 pipes (approx. R1¼", approx. 28 ins
long) for placing underneath the boiler to act as rollers
– Cleaning blade and/or chemical cleaning agent for wet
cleaning
2.7 Disposal
VDispose of boiler packaging in an environmentally
responsible manner.
VAll heating system components that have to be
replaced should be disposed of in environmentally
responsible manner at an authorized disposal site.
If an ASME CSD1 high water temperature
cut off is installed on the boiler supply (B-kit)
the following must be observed.
VThe default setting of the BC10 boiler con-
trol is 5 minutes circulator pump post
purge. This setting may be increased but
not decreased.
VIf the circulator pump is operated by an
external control a 5 minutes post purge
period must be ensured.
Caution: Risk of system damage due to un-
suitable heating system water.
VIf oxygen-permeable pipes are used, e.g.
for underfloor heating systems, the sys-
tems must be separated from one another
by heat exchangers. Unsuitable heating
system water promotes sludge and corro-
sion formation. This can result in heat ex-
changer malfunction and damage.
A PC with Buderus Logamatic ECO-Soft
4000/EMS and a service key can also be
used as a monitoring device.

2
Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice 9
2.8 Product description
The Logano plus GB312 (ÆFig. 1) is supplied with a fully
factory-fitted and ready-wired Logamatic BC10 basic pro-
grammer (ÆFig. 2, page 10).
Fig. 1 Logano plus GB312 - main components
1Programmer (MC10 and BC10)
2Gas burner
3Boiler front panel
4Trap
5Boiler heat exchanger with insulation
6Burner control unit
7Gas valve
8Boiler outer jacket
9B-kit with flow check valve (supplied as standard, not fac-
tory installed)
10 Gas isolating valve (supplied as standard, not factory
installed)
11 Mating flange, 2½" (included in B-kit, not factory installed)
12 Bolts, washers, Lock washers and nuts (to mount supply
manifold and mating flanges)
The main components of the Logano plus GB312
(ÆFig. 1) are:
–Programmer
– Frame and jacket
– Boiler heat exchanger with insulation
– Gas burner
– B-kit (standard B-kit comprising temperature/pressure
gauge, pressure relief valve, supply manifold, flow
check valve, mating flange for flow/return piping, not
factory installed)
– Gas isolating valve
The programming unit monitors and controls all electrical
boiler components.
The boiler heat exchanger transfers the heat generated by
the burner to the heating water. The thermal insulation
reduces radiant and standby heat loss.
7 747 010 720-01.3RS
10
11
12

2Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice
10
Fig. 2 Logamatic BC10 basic programmer - controls
1On/off switch
2Dial for DHW set point
3“DHW heating” LED
4Status display screen
5Control knob for maximum boiler temperature
6“Heat demand” LED
7Base plate with slot for a programming unit e.g. RC35
(behind the cover panel)
8“Burner” LED (ON/OFF)
9Socket for connecting diagnostic plug
10 “Status display” button
11 “Flue gas test” button
12 “Reset” button
Logamatic BC10 basic programmer (ÆFig. 2). The Log-
amatic BC10 basic programmer enables basic operation
of the heating system. It provides functions such as the
following for that purpose:
– Turning the heating system on/off
– Setting the DHW temperature and the maximum boiler
temperature in heating mode
– Status display
On overall picture of the controls of the Logamatic BC10
basic programmer can be obtained from Fig. 2.
Many other functions for the convenient control of your
heating system are available with a programming unit
(such as the RC35*).
* Available separately
1
2 3 4 5 6
789101112 7 747 010 720-85.1RS

2
Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice 11
2.9 Package contents
The Logano plus GB312 is supplied complete with BC10
basic control unit and MC10 programming unit.
VOn delivery, check that the packaging is undamaged.
VCheck that all package contents are present.
VDispose of packaging in an environmentally responsi-
ble manner.
Accessories
A wide range of accessories for the boiler is available.
Refer to the catalog for precise details of suitable acces-
sories.
The following accessories are available from the trade:
– Flue system
– Air supply system
– Programming unit, e.g. RC35
Component Packaging
Boiler (fully assembled with outer
casing, Logamatic MC10 program-
ming unit, BC10 and gas isolating
valve)
1 box on a pallet
Technical documentation 1 foil package
Set of adjustable feet 1 foil package
B-kit (temperature/pressure gauge,
pressure relief valve, flow connector,
flow/return mating flange, flow check
valve)
1 box

2Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice
12
2.10 Dimensions and specifications
2.10.1 Logano plus GB312 dimensions
Fig. 3 Connections and dimensions for Logano plus GB312 (sizes in inches)
AA = Flue connection
AL = Combustion air pipe connection (balanced flue opera-
tion only)
VK = Boiler supply
AKO = Condensate outlet
GAS = Gas connection + main isolating valve
ST = Pressure relief valve connection
RK = Boiler return
TM = Pressure/temperature gauge
Boiler size (output - no. of heat exchanger
sections) Unit 90 - 4 120 - 4 160 - 5 200 - 6 240 - 7 280 - 8
Width B Inches 39.1 47.3 55.5
Dimension XAA Inches 13.1 15.1 17.2 19.2 21.3
Dimension XRK (= XAL = XGAS) Inches 10.6 14.7 10.6 14.7 10.6
Dimension F Inches 31.5 39.7 47.9
Dimension A Inches 51.5 51.2
AA = Flue pipe diameter Inches 6.3 7.9
Flue adaptor for desired manufacturer's flue
system
6.3" x 5" 6.3" x 6" 7.9" x 8"
Dimension YAA Inches 18.5 19.5
Dimension ZAA Inches 5.7 12.2
AL = Diameter of combustion air pipe (bal-
anced flue only)
Inches 3.94
Connections VK and RK 2½" NPT
Tab. 1 Dimensions and connection sizes

2
Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice 13
2.10.2 Specifications
Connection ST (B-kit) ¾" NPT 1" NPT
Diameter GAS 1" NPT 1 ¼" NPT
Boiler size (output - no. of heat exchanger
sections) Unit 90 - 4 120 - 4 160 - 5 200 - 6 240 - 7 280 - 8
Tab. 1 Dimensions and connection sizes
Observe all standards and guidelines appli-
cable to the installation and operation of the
heating system in your country. The informa-
tion on the boiler rating plate is definitive and
it is imperative that it is observed.
Boiler size (output - no. of heat exchanger sec-
tions) Unit 90 - 4 120 - 4 160 - 5 200 - 6 240 - 7 280 - 8
Natural gas (gas type A)
I-B-R Input max. load Btu/hr 328,300 440,500 588,300 732,600 880,700 1,028,800
min. load Btu/hr 132,200 132,200 176,500 219,800 264,200 308,600
I-B-R gross output 180/80 ° F max. load Btu/hr 305,000 409,000 544,000 676,000 810,000 944,000
I-B-R net rating 180/80 ° F max. load Btu/hr 265,000 356,000 473,000 588,000 704,000 821,000
Rated heat ouput 122/86 ° F max. load Btu/hr 307,100 409,500 545,900 682,400 819,000 955,400
(50/30 ° C) min. load Btu/hr 128,100 127,400 171,200 212,300 255,200 298,100
Flue gas mass flow rate 180/80 ° F max. load lb/min 4.85 6.53 9.14 11.40 13.88 16.15
Flue gas mass flow rate 122/86 ° F max. load lb/min 5.05 7.12 9.29 11.61 14.02 16.65
Flue gas temperature 180/80 ° F max. load ° F 83 90 127 138 140 134
Flue gas temperature 122/86 ° F max. load ° F 120 133 129 131 131 135
CO2 content, natural gas max. load %9.1
(GAS A) min. load
Available flue pressure in. W.C. 0.4 (100 Pa)
(flue draft + air supply pressure)
Air supply volumetric flow rate cfm 95 95 130 160 190 220
Blower G1G 170
Honeywell gas valve V4730C1071 V4730C1097 V4730C10
63
Gas injector diameter
Natural gas (GAS A) calorific value 1075 BTU/ft3 17.0
Heating water circuit
Boiler water capacity US gal-
lons 4.2 4.2 5.3 6.3 7.1 7.9
Primary pressure drop psi ÆFig. 4 (graph)
Maximum flow temperature, heating/hot water
mode ° F 180/180
High temperature cut-out safety limit (manual
reset high limit setting)° F 200
Permissible operating pressure psi 50
Electrical data
Enclosure class IP 40
Mains power supply V/Hz 120 V / 60 Hz
Power consumption max. load W84 150 190 230 270 370
min. load W40 40 45 50 50 50
Maximum permissible fuse rating A10
Appliance dimensions and weight
Transport clearance dimensions, width x depth x
height Inches 34x25x60 42x25x60 50x25x60
Weight lbs 455 530 585 665 730
Tab. 2 Specifications

2Details of the product
Logano plus GB312 - Technical specifications are subject to change without prior notice
14
Fig. 4 Primary circuit flow resistance, GB312 with check valve
xFlow rate in gal/min (GPM)
yPrimary pressure drop in psi
The boiler is factory-set for:
– Natural gas (gas type A)
0,1
1
10
100
1 10 100 1000
x
y
90-4
120-4
160-5
200-6
240-7
280-8
7 747 010 720-30.1RS
Boiler rating Gas flow rate
Natural gas (gas type A)
Calorific value 1075 BTU/ft3
cu ft/hr
90 - 4 324.6
120 - 4 434.4
160 - 5 579.0
200 - 6 720.6
240 - 7 868.8
280 - 8 1013.4
Tab. 3 Gas flow rate (based on gas temperature of 60
°F and air pressure of 30 ins Hg)

3
Transporting the boiler
Logano plus GB312 - Technical specifications are subject to change without prior notice 15
3 Transporting the boiler
This section describes how to move the boiler safely and
without damaging it.
3.1 Lifting and carrying the boiler
The boiler can be carried to its installation site using 2
pipes (1¼", approx. 80 inches long).
VUnscrew the locking screw from the top centre of the
boiler front panel.
VLift font panel slightly and draw forwards to remove.
VUnscrew the locking screws from the side panels at the
front and back of the boiler.
VSlightly lift the side panels and remove.
Fig. 5 Removing front and side panels
1Front panel
2Side panel
3Locking screw
Caution: Risk of system damage due to im-
pacts.
The boiler as delivered contains components
that are sensitive to shocks.
VIf the boiler has to be moved after delivery,
protect all components against shocks
and impacts.
VObserve the transport instructions on the
packaging.
If the boiler is not to be installed immediately,
protect the connections from entry of dirt.
Dispose of packaging in an environmentally
responsible manner.

3Transporting the boiler
Logano plus GB312 - Technical specifications are subject to change without prior notice
16
VUnscrew the securing screws.
VLift the boiler off the pallet.
Fig. 6 Lifting the boiler off the pallet.
1Locking screw
2Pallet
VPush the pipes through the holes at the front and rear
of the boiler (ÆFig. 7 ).
VSecure the pipes against slipping in the positions
shown in Fig. 7, using adhesive tape for example.
VCarry the boiler to the installation site.
Fig. 7 Transporting the boiler using pipes
1Positions for securing the boiler against slipping
2Pipe (for carrying)
7 747 010 720-06.1RS
1
1
2
Caution: Risk of injury from carrying heavy
loads.
VAlways lift and move the appliance with
the assistance of another person and us-
ing the grip positions shown.
VSecure the boiler against slipping.
7 747 010 720-07.1RS

3
Transporting the boiler
Logano plus GB312 - Technical specifications are subject to change without prior notice 17
3.2 Transporting the boiler on rollers
If the route to the installation site is flat, the boiler can also
be rolled. This requires at least 5 lengths of pipe approx.
28 inches long (diameter 1¼") to be placed underneath
to act as rollers.
VLay the lengths of pipe on the floor spaced about 16
inches apart.
VLift the boiler onto the lengths of pipe and carefully
transport it to the boiler room.
Fig. 8 Transporting the boiler on rollers (dimensions in
inches)
You can also use standard transport rollers.
VSo that the bottom plate is not pressed in,
it is essential to ensure that the weight is
evenly distributed across the load-bearing
parts.
7 747 010 720-08.1RS

4Installing the boiler
Logano plus GB312 - Technical specifications are subject to change without prior notice
18
4 Installing the boiler
This section explains how to erect and position the boiler
correctly in the boiler room.
4.1 Boiler room requirements
Warning: Risk of system damage due to
freezing.
VInstall the heating system in a frost-free
room.
Danger: Dangers posed by explosive and
easily combustible materials.
VDo not use or store easily combustible ma-
terials (paper, lace curtains, clothing, thin-
ners, paints, etc.) near the boiler.
VMaintain a clearance of 16 inches from the
boiler.
Warning: Risk of boiler damage from con-
taminated combustion air.
VDo not use cleaning agents that contain
chlorine or halogenated hydrocarbons
(e.g. in spray cans, solvents and cleaning
agents, paints, glues).
VDo not store or use such substances in the
boiler room.
VAvoid excessive dust accumulation (build-
ing dust) on or near the boiler.

4
Installing the boiler
Logano plus GB312 - Technical specifications are subject to change without prior notice 19
4.2 Recommended wall clearances
When deciding on the installation site, the clearances for
the flue piping and the connecting pipes must be
observed (ÆFig. 9 and Section 6, Connecting the flue
system and water and gas piping).
Fig. 9 Wall clearances in the boiler room
4.3 Leveling the boiler
To prevent air collecting in the boiler and to allow the con-
densate to drain freely from the condensate pan, the
boiler must be leveled.
VPlace the boiler in its final position.
VLevel the boiler horizontally by turning the adjustable
feet and using a spirit level.
Fig. 10 Leveling the boiler
1Adjustable feet
2Spirit level
Dimension Wall clearance (inch)
minimum
Recom-
mended
A2028
B1)
1) This clearance dimension is dependent on the flue system fitted
22 28
C2028
D20 28
E1) 614
Tab. 4 Recommended and minimum wall clearances
(dimensions in inches). It is imperative that the
minimum clearance (dimension E) is main-
tained.
Where applicable, allow extra wall clearanc-
es for additional components such as DHW
tank, pipe connections or other flue compo-
nents, etc.
7 747 010 720-09.1RS
A
D
B
E
C
Caution: Risk of boiler damage due to inad-
equate load-bearing capacity of floor or un-
suitable base.
VMake sure that the surface on which the
boiler stands has sufficient load-bearing
capacity.
VThe boiler may stand on a base made of
combustible material but not on carpet.
7 747 010 720-10.1RS

5Openings for combustion air supply and venting
Logano plus GB312 - Technical specifications are subject to change without prior notice
20
5 Openings for combustion air supply and venting
To ensure an adequate combustion air supply and venting
of the heating system, suitable measures must be taken in
accordance with the National Fuel Gas Code, NFPA 54
(ANSI Z223.1), Section 5.3, Air for Combustion and Ven-
tilation, or the local building code. In Canada the regula-
tions in accordance with CAN/CSA B 149.1 and 2
Installation Codes apply.
Overall air supply within the building
Make sure that the boiler room has two permanent air
vents that are connected to one or more other rooms.
When calculating the cross-sectional areas of the vent
apertures, the total burner output of all gas-fired appli-
ances in the connected rooms must be taken into
account. Each vent must have a minimum cross-section of
one square inch per 1000 Btu/h of the total burner output
of all gas-fired appliances inside the connected rooms.
Make sure that the cross-sectional area of each vent is at
least 100 square inches. One of the vents must be no
more than 12" from the ceiling and the other no more than
12" from the floor of the boiler room, measured from the
outer edge of the vent aperture. The smallest dimension
of all inlet and outlet vents must be not less than 3".
Total air supply from outside the building
Make sure that the boiler room has two permanent air
vents, one of which must not be more than 12" from the
ceiling and the other not more than 12" from the floor of
the boiler room, measured from the outer edge of the vent
aperture. The vents must be connected either directly or
via air ducts to the outside or to rooms that have an unob-
structed connection to the open air (crawl passage or roof
space). The smallest dimension of all inlet and outlet vents
must be not less than 3".
Caution: Risk of boiler damage and mal-
functions due to missing or inadequate open-
ings for combustion air and venting of the
boiler room.
The openings for combustion air supply and
venting are always required regardless of
whether the combustion air is drawn from the
room (conventional flue) or supplied directly
to the boiler through ducts (balanced flue).
Inadequate venting of the boiler room
may result in excessive ambient tem-
peratures. This can damage the boiler.
Inadequate combustion air supply may
cause malfunctions in operation.
VMake sure that air inlet or outlet vents are
not closed off or their size reduced and
that they are adequately dimensioned.
VThe boiler must not be operated until the
obstruction has been removed.
VDraw the operator's attention to any defi-
ciencies and the potential dangers.
Caution: Risk of boiler damage from con-
taminated combustion air.
VNever use cleaning agents that contain
chlorine or halogenated hydrocarbons
(e.g. in spray cans, solvents and cleaning
agents, paints, glues).
VDo not store or use such substances in
the boiler room.
VAvoid excessive dust accumulation.
If impurities in the combustion air are possi-
ble (e.g. installation near swimming pools, dry
cleaners or hairdressing salons), operation
independent of room air is recommended.
Caution: Dangers posed by explosive and
easily combustible materials.
VDo not use or store easily combustible ma-
terials (paper, lace curtains, clothing, thin-
ners, paints, etc.) near the boiler.
VMaintain a clearance of 16 inches from the
boiler.