Buderus Logano GC 124 II User manual

WARNING!
This conversion kit must only be installed by a qua-
lified heating contractor as specified by the manuf-
acturer’s instructions and the applicable rules and
regulations of the local authorities. If these instruc-
tions are not followed exactly, a fire, explosion or
release of carbon monoxide may occur with
serious property damage or loss of life and serious
injury. The heating contractor is liable for correct
conversion of the heating system with this conver-
sion kit.
CAUTION!
Before converting the heating system to a different
type of gas the gas line must first be shut off and
then the power to the heating system must be dis-
connected.
Note:
Please keep these instructions for future refer-
ence.
In the Commonwealth of Massachusetts this boiler
must be installed by a licensed plumber or gas fit-
ter.
Conversion instructions from
natural gas to propane
Gas boiler
Logano GC 124 II
C
6 720 804 435 (2012/09) EN-US

Contents
Logano GC 124 II – 6 720 804 435 (2012/09)2
Contents
1 Safety considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Key to symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Safety instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Product information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Correct use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 Conversion to propane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4 Start-up instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1 Starting up boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1.1 Prepare pressure measurement . . . . . . . . . . . . . . . . . . . 6
4.1.2 Turning on heating system . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Final start-up procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1 Safety considerations
1.1 Key to symbols
Warnings
The following keywords are defined and can be used in this document:
•NOTE indicates a situation that could result in damage to property or
equipment.
•CAUTION indicates a situation that could result in minor to medium
personal injury.
•WARNING indicates a situation that could result in severe personal
injury or death.
•DANGER indicates a situation that will result in severe injury or death.
Important information
Additional symbols
1.2 Safety instructions
Risk to life through the explosion of volatile gases
BWork on gas components must be carried out by qualified and
authorized personnel only.
Risk to life from electric shock.
BDisconnect the power supply to the heating system before conducting
any work on it, e.g. switch off the heating emergency switch outside
the boiler room.
BIt is not sufficient just to switch off the control.
Warnings in this document are identified by a warning
triangle printed against a grey background.
Keywords at the start of a warning indicate the type and
seriousness of the ensuing risk if measures to prevent
the risk are not taken.
This symbol indicates important information where
there is no risk of personal injury or property damage.
Symbol Explanation
BStep in an action sequence
ÆCross-reference to another part of the document
•List entry
– List entry (second level)
Table 1

2
Product information
Logano GC 124 II – 6 720 804 435 (2012/09) 3
2 Product information
2.1 Correct use
This conversion kit and the accompanying instructions are for
conversion of GC124 II special gas-fired boilers from natural gas to
propane.
Requirements
2.2 Scope of delivery
•Honeywell gas solenoid valve conversion kit
# 393 691, comprising:
–black safety screw
–pressure adjustment screw
–red spring
–yellow label for gas valve
•GC124 II: BBR 12 pilot gas orifice
•Main gas orifices and seals
•"Conversion to propane" label (to be filled out and attached to the
unit)
•Technical documents
3 Conversion to propane
For your own safety read the instructions before conversion.
The following instructions must be followed for conversion of the
boiler to propane:
BIf the boiler was in operation, close the gas shut-off. Otherwise open
boiler front door.
BSet room thermostat (optional) to the lowest value.
BDisconnect the heating system from the power supply.
BOpen boiler front door.
Fig. 1 Opening boiler front door
Fig. 2 Gas valve
[1] ON/OFF knob (shown in ON position)
BTurn gas valve ON/OFF knob clockwise to OFF position. Do not use
force.
GC124 II–18
74 MBtu/hr
GC124 II-25
103 MBtu/hr
GC124 II-32
132.5 MBtu/hr
Table 2 Requirements
WARNING: Risk to life through not observing the
conversion instructions.
BIf you wish to convert the boiler for operation with
propane, the conversion from natural gas to propane
must be carried out first as specified by the attached
conversion instructions.
WARNING: Danger to life through fire or explosion.
BNever use excessive force on the ON/OFF knob
(Æfigure 2).
BTurn ON/OFF knob only by hand.
BNever use tools to turn knob.
BIf you are unable to turn the knob by hand, do not try
to repair it.
BCall Buderus technical service for assistance.
6 720 804 435-01.1
T
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6 720 804 435-02.1T

3Conversion to propane
Logano GC 124 II – 6 720 804 435 (2012/09)4
BIf there is no sign of a gas odor, continue with the next step.
Removing burner
BSecure gas manifold with wire or cord.
BRemove igniter cable from ignition module (Æfigure 3, [6]).
BDisconnect cable connector from bottom of gas valve
(Æfigure 3, [3]).
BLabel cables to the flame roll-out switch, then remove cable
(Æfigure 3, [2]).
Fig. 3 Front view
[1] Flame roll-out switch
[2] Flame roll-out switch cable
[3] Gas valve
[4] Gas supply pipe
[5] Aquastat
[6] Ignition module
[7] Igniter cable
[8] Gas valve cable connector
[9] Pilot line
[10] Igniter cable
Fig. 4 Removing burner
[1] Screw nuts (two)
[2] Screws on gas manifold on top of gas valve (four)
BRemove four (4) screws from gas manifold on top of gas valve.
BRemove two (2) screw nuts on burner tray and take out the tray.
Replacing main gas orifices
BInstall the new main gas orifices and copper gasket. Check with
table 3 that the correct orifices for operation of the boiler are
installed.
WARNING: Risk to life through the explosion of volatile
gases.
BWait five (5) minutes until all gas residues have
dissipated. Check whether there is any smell of gas,
including at floor level. If you can smell gas, close the
gas shut-off and disconnect the heating system from
the power supply and contact the customer service
technician or the gas company.
6 720 804 435-03.1T
8
9
10
1
2
5
6
7
3
4
These orifice sizes are exclusively for installations 0-
8500 feet above sea level.
Orifice sizes for propane
Model GC124-18 GC124-25 GC124-32
Orifice size 180 175 170
Qty 234
Table 3 Orifice sizes for propane
These values are applicable for the U.S.A. only.
for altitudes of 0 - 8500 ft.
2
6 720 804 435-04.1T
1

3
Conversion to propane
Logano GC 124 II – 6 720 804 435 (2012/09) 5
Converting gas valve
BRemove the safety screw [1] for the manifold pressure adjustment on
the gas valve.
BRemove manifold pressure adjustment screw [2].
BRemove stainless steel spiral spring [3].
BInstall the red spring from the Honeywell conversion kit in the gas
valve.
BScrew in the new gas adjustment screw from the Honeywell
conversion kit until it is flush with the top of the gas valve.
Then screw the manifold pressure adjustment screw six (6)
revolutions clockwise. This corresponds to a pressure preset of
approx. 10.0 W.C. This setting must be checked with a pressure
gauge on completion of the conversion (Æchapter 4, page 6).
BInstall new black safety screw from the Honeywell conversion kit.
BClean the gas valve housing [4] and attach the yellow label [5] from
the Honeywell LP conversion kit to a visible spot on the gas valve.
Fig. 5 Gas valve
[1] Safety screw
[2] Manifold pressure adjustment screw
[3] Stainless steel spiral spring
[4] Gas valve
[5] Yellow label
Removing pilot burner and replacing pilot gas orifice
BUnscrew ignition burner unit from burner.
BRemove pilot orifice.
BPosition the new BBR 12 pilot gas orifice in pilot burner unit.
BScrew the pilot line to the pilot burner unit.
BScrew the pilot burner unit to the main burner.
BCheck that the pilot burner unit is correctly seated compared to the
main burner.
BRecord the required information on the
conversion label and attach on the outside of the boiler jacket as close
as possible to the nameplate.
Fig. 6 Pilot burner
[1] Ignition cable
[2] Ignition electrode
[3] Pilot gas line
[4] Pilot gas line retaining screws
Carrying out leak test
BOpen manual gas shut-off in the gas line.
BCheck the gas supply line to the gas shut-off for leaks with soap
solution. If no leaks are found, continue with the step after the next
step. If any leaks were found, close gas shut-off.
BSeal leaks and repeat the previous step.
BWait five (5) minutes until all gas residues have dissipated. Then
check for a gas odor, including at floor level, because many types of
gas are heavier than air.
BAlways follow the start-up instructions on the next page.
32
1
5
4
6 720 804 435-05.1T
When installing the pilot gas orifice, make sure that the
pilot gas orifice is correctly threaded and tightened.
1
3
2
4
6 720 804 435-06.1T

4Start-up instructions
Logano GC 124 II – 6 720 804 435 (2012/09)6
4 Start-up instructions
For your own safety, read before boiler start-up.
4.1 Starting up boiler
BSTOP! First perform a leak test as described on page 5 of this manual.
BFirst read the safety instructions on this page.
4.1.1 Prepare pressure measurement
BRemove the screw plug for the gas pressure measurement port on the
gas valve. Install pressure measuring nipple and attach a pressure
gauge to measure the gas pressure.
BRemove the screw plug for the orifice pressure measurement port on
the gas valve. Install pressure measuring nipple and attach a pressure
gauge to measure the orifice pressure.
BOpen gas shut-off.
Fig. 7 Gas valve
[1] ON/OFF knob (shown in ON position)
[2] Screw plug for gas pressure measurement port
[3] Screw plug for orifice measurement port
[4] Ignition gas line connection
4.1.2 Turning on heating system
The boiler is fully functional with the factory-installed aquastat and field
installed and connected vent damper.
BSwitch on power to the heating system, continue to chapter 5
(Æpage 7).
BVerify that the thermostat (optional) signals a heat demand to the
boiler (set temperature dial at least 10°F above ambient).
Fig. 8 ON/OFF switch
[1] Emergency shutoff switch
WARNING: Risk to life due to not observing the start-up
instructions and resulting malfunction.
BIf these instructions are not followed exactly, fire or
explosion may result causing serious property
damage, loss of life, or serious personal injury.
BObserve the installation instructions.
WARNING: Danger of explosion
If you smell gas there is danger of explosion!
BNo open flame! No smoking!
BPrevent spark generation. Never operate electrical
switches, including telephones, plugs or door bells!
BClose main gas shut-off!
BOpen windows and doors!
BWarn all occupants of the building!
BEvacuate the building!
BCall gas company, heating contractor or fire
department from outside the building.
This unit is equipped with an automatic igniter that starts
the burner. Do not attempt to ignite the burner manually.
WARNING: Risk to life due to water damage.
BDo not operate the unit if any part is or was
submerged in water.
BContact a qualified customer service technician
immediately to have the unit checked and all parts of
the control and gas valves replaced that were in
contact with water.
2
1
4
6 720 804 435-07.1T
3
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5
Final start-up procedures
Logano GC 124 II – 6 720 804 435 (2012/09) 7
5 Final start-up procedures
Verifying the ignition spark
BLook through the sight glass at the igniter and verify that a spark is
visible.
Fig. 9 GC124 II
[1] Sight glass
BShould no spark be visible continue to troubleshooting procedure in
the installation and service manual.
BTurn ON/OFF knob (Æfigure 10) counterclockwise to the ON
position.
BThe ignition flame will appear and ignite the main burner. If the main
burner does not ignite, close the gas shut-off. Disconnect heating
system from the power source and inform your customer service
technician or gas company.
Fig. 10 Gas valve
[1] ON/OFF knob (shown in ON position)
Checking gas supply pressure
BCheck the gas supply pressure while the boiler is operating. The
connection pressure for natural gas must be between 4.7" and 10.5"
W.C. For propane gas (LP) it must be between 11" and 13" W.C. If the
gas pressure is in the correct range, record the measured value in the
start-up protocol, then continue with the next step. If the supply
pressure does not meet the above criteria, close gas line and contact
the gas company.
Checking orifice pressure
BCompare the orifice pressure with the values in table 4. If it differs by
more than 0.2" W.C., adjust accordingly. To set the orifice pressure,
the protective screw on the gas valve must be removed (Æfigure 11,
page 8). Turn the adjustment screw clockwise to increase the
pressure, and counterclockwise to reduce the pressure. This setting
must be adjusted while the boiler is operating.
WARNING: Risk to life from fire or explosion.
BNever use excessive force on the ON/OFF knob
(Æfigure 10).
BTurn ON/OFF knob only by hand.
BNever use tools to turn knob.
BIf you are unable to turn the knob by hand, do not try
to repair it.
BCall Buderus technical service for assistance.
1
6 720 804 435-09.1T
GC124 II
Natural Gas
[inch W.C.]
LP
[inch W.C.]
18 3.5 8.8
25 3.5 8.6
32 3.5 8.7
Table 4 Orifice pressure at 60°F / 30" Hg. These values are only valid in
the U.S.A. and only for elevations from
0-8500ft.
1
6 720 804 435-10.1T

5Final start-up procedures
Logano GC 124 II – 6 720 804 435 (2012/09)8
Fig. 11 Gas valve
[1] ON/OFF knob (shown in ON position)
[2] Safety screw on gas supply pressure measurement port
[3] Safety screw on orifice pressure adjustment port
[4] Safety screw on orifice pressure measurement port
[5] Safety screw on ignition gas adjustment screw
BRecord the measured value in the start-up protocol. Install the safety
screw back into the gas valve.
BObserve main burner flame through the sight glass (Æfigure 9,
page 7) in the burner plate. The flame must show a steady and stable
body and generally be of bluish color. If the main burner flame meets
the requirements, continue with the next step. If the main burner
flame is weak, yellow, or goes out, turn the ON/OFF knob
(Æfigure 13, page 8) on the gas valve clockwise to OFF. Close the
gas shut-off and disconnect the heating system from the main power
source and contact the customer service technician or the gas
company.
Checking flame rod
BTest the flame rod by closing the gas shut-off. The main burner flame
(Æfigure 12, page 8) and the ignition flame are extinguished. After
no more than six (6) seconds the main gas solenoid valve on the gas
valve must close with an audible noise. If the gas valve does not
operate correctly, turn ON/OFF knob on the gas valve clockwise to the
OFF position immediately. Close the main gas shut-off and disconnect
the heating system from the main power source and contact the
customer service technician or the gas company.
BAfter 90 seconds the igniter stops generating sparks for five (5)
seconds.
BDisconnect the heating system from the main power source. Open
main gas shut-off. A normal operating cycle must follow.
BIf the main burner flame lights and burns to spec, continue with the
next step. If not, turn knob on gas valve clockwise to OFF position
immediately. Close main gas shut-off. Disconnect heating system
from the power source and inform the customer service technician or
gas company.
BTurn gas valve ON/OFF knob clockwise to OFF position.
BClose main gas shut-off.
BDisconnect heating system from the power source and set the
thermostat to the lowest setting.
BRemove pressure measuring nipple and pressure gauge for measuring
gas pressure and orifice pressure from the gas valve, and close the
openings with the screw plugs.
Fig. 12 Main burner
[1] Main burner flame
Fig. 13 Gas valve
[1] ON/OFF knob (shown in ON position)
Checking for leaks
BOpen main gas shut-off.
BSet thermostat at least 10°F above ambient to establish a heat
demand.
BTurn main power switch ON.
BTurn gas valve ON/OFF knob counterclockwise to ON position.
BAfter the burner has lit check the gas valve including screw plugs for
leaks using soapy water. If no leaks are found, continue with the step
after the next step. If leaks are found, close gas shut-off and turn ON/
OFF knob on gas valve clockwise to the OFF position. Disconnect the
heating system from the power source and turn thermostat to its
lowest setting.
BSeal leaks. Repeat all steps in this paragraph.
BCarefully wipe away the soapy water to prevent corrosion caused by
the alkaline content of the soap.
1
54
6 720 804 435-11.1T
3
2
1
6 720 804 435-12.1T
1
6 720 804 435-13.1T

5
Final start-up procedures
Logano GC 124 II – 6 720 804 435 (2012/09) 9
Checking the vent damper
BCheck the position of the vent damper. The damper must be fully open
(vertical). When burner is on flue gases must not escape from the
open draft hood.
Fig. 14 Checking vent damper
[1] Open draft hood
[2] Vent connection
[3] Vent damper
[4] Damper blade position indicator
[5] Vent damper motor
[6] Flue gas collector
[7] Boiler
Checking aquastat
Check the function of the maximum aquastat to make sure that it
switches the boiler off as soon as the boiler water temperature set at the
aquastat is reached. Record the result in the start-up protocol.
BSet aquastat to its desired setting.
BReplace front door and close.
Fig. 15 Checking temperature control
[1] Adjustment keypad
WARNING: Risk of life due to leaking flue gases.
BVerify the functionality and operability of the vent
damper.
4
3
2
1
5
6
7
6 720 804 435-14.1T
6 720 804 435-15.1T
1

5
Logano GC 124 II – 6 720 804 435 (2012/09)10
Notes

5
Logano GC 124 II – 6 720 804 435 (2012/09) 11
Notes