Buderus Logano GC 124 II, Logano GC124 II-18, Logano GC124 II-25, Logano GC124 II-32 User Manual

Conversion instructions from
natural gas to propane

Gas boiler

WARNING!

This conversion kit must only be installed by a qua­lified heating contractor as specified by the manuf­acturer’s instructions and the applicable rules and
regulations of the local authorities. If these instruc­tions 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 conver­sion 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 dis­connected.

Note:

Please keep these instructions for future refer­ence.

Logano GC 124 II

In the Commonwealth of Massachusetts this boiler
must be installed by a licensed plumber or gas fit­ter.

6 720 804 435 (2012/09) EN-US

C

Contents

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

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.

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

This symbol indicates important information where
there is no risk of personal injury or property damage.

Additional symbols

Symbol Explanation

B Step in an action sequence

Æ Cross-reference to another part of the document

• List entry
– List entry (second level)

Table 1

1.2 Safety instructions

Risk to life through the explosion of volatile gases

B Work on gas components must be carried out by qualified and

authorized personnel only.

Risk to life from electric shock.

B Disconnect 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.

B It is not sufficient just to switch off the control.

Logano GC 124 II – 6 720 804 435 (2012/09)2

2 Product information

T

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

GC124 II–18
74 MBtu/hr

GC124 II-25
103 MBtu/hr

GC124 II-32

132.5 MBtu/hr

Table 2 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.

WARNING: Risk to life through not observing the
conversion instructions.

B If 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.

Fig. 1 Opening boiler front door

WARNING: Danger to life through fire or explosion.

B Never use excessive force on the ON/OFF knob

(Æ figure 2).

B Turn ON/OFF knob only by hand.
B Never use tools to turn knob.
B If you are unable to turn the knob by hand, do not try

to repair it.

B Call Buderus technical service for assistance.

Product information

6 720 804 435-01.1

2

The following instructions must be followed for conversion of the
boiler to propane:

B If the boiler was in operation, close the gas shut-off. Otherwise open

boiler front door.

B Set room thermostat (optional) to the lowest value.
B Disconnect the heating system from the power supply.
B Open boiler front door.

1

6 720 804 435-02.1T

Fig. 2 Gas valve

[1] ON/OFF knob (shown in ON position)

B Turn gas valve ON/OFF knob clockwise to OFF position. Do not use

force.

Logano GC 124 II – 6 720 804 435 (2012/09) 3

3

Conversion to propane

WARNING: Risk to life through the explosion of volatile

gases.
B Wait 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.

B If there is no sign of a gas odor, continue with the next step.

Removing burner

B Secure gas manifold with wire or cord.
B Remove igniter cable from ignition module (Æ figure 3, [6]).
B Disconnect cable connector from bottom of gas valve

(Æ figure 3, [3]).

B Label cables to the flame roll-out switch, then remove cable

(Æ figure 3, [2]).

5

6

7

8

2

1

6 720 804 435-04.1T

Fig. 4 Removing burner

[1] Screw nuts (two)
[2] Screws on gas manifold on top of gas valve (four)

B Remove four (4) screws from gas manifold on top of gas valve.
B Remove two (2) screw nuts on burner tray and take out the tray.

9

Replacing main gas orifices

B Install the new main gas orifices and copper gasket. Check with

table 3 that the correct orifices for operation of the boiler are
installed.

4

3

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

1

2

6 720 804 435-03.1T

10

These orifice sizes are exclusively for installations 0­8500 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.

Logano GC 124 II – 6 720 804 435 (2012/09)4

Conversion to propane

3

Converting gas valve

B Remove the safety screw [1] for the manifold pressure adjustment on

the gas valve.

B Remove manifold pressure adjustment screw [2].
B Remove stainless steel spiral spring [3].
B Install the red spring from the Honeywell conversion kit in the gas

valve.

B Screw 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 (Æ chapter 4, page 6).

B Install new black safety screw from the Honeywell conversion kit.
B Clean 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.

1

32

Removing pilot burner and replacing pilot gas orifice

B Unscrew ignition burner unit from burner.
B Remove pilot orifice.
B Position the new BBR 12 pilot gas orifice in pilot burner unit.

When installing the pilot gas orifice, make sure that the
pilot gas orifice is correctly threaded and tightened.

B Screw the pilot line to the pilot burner unit.
B Screw the pilot burner unit to the main burner.
B Check that the pilot burner unit is correctly seated compared to the

main burner.

B Record the required information on the

conversion label and attach on the outside of the boiler jacket as close
as possible to the nameplate.

2

4

3

1

4

5

Fig. 5 Gas valve

[1] Safety screw
[2] Manifold pressure adjustment screw
[3] Stainless steel spiral spring
[4] Gas valve
[5] Yellow label

6 720 804 435-05.1T

6 720 804 435-06.1T

Fig. 6 Pilot burner

[1] Ignition cable
[2] Ignition electrode
[3] Pilot gas line
[4] Pilot gas line retaining screws

Carrying out leak test

B Open manual gas shut-off in the gas line.
B Check 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.

B Seal leaks and repeat the previous step.
B Wait 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.

B Always follow the start-up instructions on the next page.

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

4

Start-up instructions

4 Start-up instructions

For your own safety, read before boiler start-up.

WARNING: Risk to life due to not observing the start-up

instructions and resulting malfunction.
B If these instructions are not followed exactly, fire or

explosion may result causing serious property
damage, loss of life, or serious personal injury.

B Observe the installation instructions.

WARNING: Danger of explosion
If you smell gas there is danger of explosion!

B No open flame! No smoking!
B Prevent spark generation. Never operate electrical

switches, including telephones, plugs or door bells!

B Close main gas shut-off!
B Open windows and doors!
B Warn all occupants of the building!
B Evacuate the building!
B Call 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.
B Do not operate the unit if any part is or was

submerged in water.

B Contact 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

3

6 720 804 435-07.1T

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.

B Switch on power to the heating system, continue to chapter 5

(Æ page 7).

B Verify that the thermostat (optional) signals a heat demand to the

boiler (set temperature dial at least 10°F above ambient).

4.1 Starting up boiler

B STOP! First perform a leak test as described on page 5 of this manual.
B First read the safety instructions on this page.

4.1.1 Prepare pressure measurement

B Remove 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.

B Remove 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.

B Open gas shut-off.

1

Fig. 8 ON/OFF switch

[1] Emergency shutoff switch

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

6 720 804 435-08.1T

5 Final start-up procedures

Verifying the ignition spark

B Look through the sight glass at the igniter and verify that a spark is

visible.

Final start-up procedures

5

1

6 720 804 435-09.1T

Fig. 9 GC124 II

[1] Sight glass

B Should no spark be visible continue to troubleshooting procedure in

the installation and service manual.

WARNING: Risk to life from fire or explosion.
B Never use excessive force on the ON/OFF knob

(Æ figure 10).

B Turn ON/OFF knob only by hand.
B Never use tools to turn knob.
B If you are unable to turn the knob by hand, do not try

to repair it.

B Call Buderus technical service for assistance.

B Turn ON/OFF knob (Æ figure 10) counterclockwise to the ON

position.

B The 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.

1

6 720 804 435-10.1T

Fig. 10 Gas valve

[1] ON/OFF knob (shown in ON position)

Checking gas supply pressure

B Check 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

B Compare 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 (Æ figure 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.

Natural Gas

GC124 II

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.

[inch W.C.]

LP
[inch W.C.]

Logano GC 124 II – 6 720 804 435 (2012/09) 7

5

Final start-up procedures

2

3

1

5

4

6 720 804 435-11.1T

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

B Record the measured value in the start-up protocol. Install the safety

screw back into the gas valve.

B Observe main burner flame through the sight glass (Æ figure 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
(Æ figure 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.

B Remove 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.

1

6 720 804 435-12.1T

Fig. 12 Main burner

[1] Main burner flame

1

Checking flame rod

B Test the flame rod by closing the gas shut-off. The main burner flame

(Æ figure 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 /OF F kn ob o n th e g as 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.

B After 90 seconds the igniter stops generating sparks for five (5)

seconds.

B Disconnect the heating system from the main power source. Open

main gas shut-off. A normal operating cycle must follow.

B If 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.

B Turn gas valve ON/OFF knob clockwise to OFF position.
B Close main gas shut-off.
B Disconnect heating system from the power source and set the

thermostat to the lowest setting.

6 720 804 435-13.1T

Fig. 13 Gas valve

[1] ON/OFF knob (shown in ON position)

Checking for leaks

B Open main gas shut-off.
B Set thermostat at least 10°F above ambient to establish a heat

demand.

B Turn main power switch ON.
B Turn gas valve ON/OFF knob counterclockwise to ON position.
B After 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.

B Seal leaks. Repeat all steps in this paragraph.
B Carefully wipe away the soapy water to prevent corrosion caused by

the alkaline content of the soap.

Logano GC 124 II – 6 720 804 435 (2012/09)8

Checking the vent damper

WARNING: Risk of life due to leaking flue gases.

B Verify the functionality and operability of the vent

damper.

B Check 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.

5

6

4

Final start-up procedures

5

3

7

2

1

6 720 804 435-14.1T

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.

B Set aquastat to its desired setting.
B Replace front door and close.

Fig. 15 Checking temperature control

[1] Adjustment keypad

Logano GC 124 II – 6 720 804 435 (2012/09) 9

1

6 720 804 435-15.1T

5

Notes

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

Notes

5

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