Conversion Instructions

Gas Conversion Kit
Bosch Thermotechnik GmbH
Junkersstrasse 20-24; D-73249 Wernau/Germany
6 720 646 558 (2010/11)
Gas type adjustment
The gas-air ratio must always be set on the basis of a CO
2
or O
2
reading taken at maximum nominal output and minimum nominal
output using an electronic flue gas analyzer.
Adjustment to different flue systems using throttle discs or baffles is
not necessary.
NG
• Appliances are set at the factory to Wobbe index 1,333 BTU/ft
3
(49.6 MJ/m
3
) at 60 °F (approx. 15 °C), 30" HG and 7.0" W.C.
(17.4 mbar) gas supply pressure and then sealed.
Converting to a different gas type
A gas conversion kit is included in the scope of delivery.
B Fold the Heatronic down.
B Check the number on the code plug from the gas conversion kit:
B Replace the code plug in the Heatronic with the code plug from the
gas conversion kit.
Fig. 1 Replacing the code plug
B Affix the gas type label from the gas conversion kit to the appliance.
Fig. 2 Affixing the gas type label
B Always adjust the gas-air ratio (CO
2
or O
2
, Æ Section “Setting the
gas-air ratio”) after converting to a different gas type and measure
the CO content of the flue gas (Æ “Installation and Service
Instructions for Contractors”).
Installation location higher than 2,000 feet (610 m) above sea level
Input and output rates will be reduced at high altitudes.
ZBR42-3A... and ZWB42-3A... have a derate of approximately 3 % per
1000 feet (305 m).
ZBR16-3A..., ZBR28-3A..., ZBR35-3A... and ZWB28-3A... do not have a
derate up to 6000 feet (1829 m). Above 6000 feet (1829 m) the derate
is approximately 3 % per 1000 feet (305 m).
B Correction of the fan speed curve of the burner:
Use service function 0.d to adjust the elevation setting.
Setting the gas-air ratio (CO
2
or O
2
)
B Switch the appliance OFF using the ON/OFF switch.
B Remove the cover (Æ “Installation and Service Instructions for
Contractors”).
B Switch the appliance ON using the ON/OFF switch.
B Open one of the flue gas test ports.
Fig. 3 Open one of the flue gas test ports
DANGER: Personal injury and property damage
B This conversion shall only be installed by a qualified
service agency in accordance with the manufacturer‘s
instructions and all applicable codes and
requirements of the authority having jurisdiction.
B If the information in these instructions is not followed
exactly or the installation, adjustment, modification,
operation or maintenance is carried out by an
unqualified person, a fire, an explosion or production
of carbon monoxide may result causing property
damage, personal injury or loss of life.
B Before carrying out electrical work: disconnect the
installation from the power supply.
B The qualified service agency is responsible for the
proper conversion of this appliance.
B The installation is not proper and complete until the
operation of the converted appliance is checked as
specified in these instructions.
DANGER: Explosion!
B Close the gas cock prior to working on the gas train.
B Check for gas leaks after carrying out work on the gas
train.
NG Code plug LPG Code plug
Appliance Order number Order number
ZBR16-3A 8 714 432 501 8 714 432 506
ZBR28-3A 8 714 432 502 8 714 432 507
ZBR35-3A 8 714 432 503 8 714 432 508
ZBR42-3A 8 714 432 504 8 714 432 509
ZWB28-3A 8 714 432 520 8 714 432 521
ZWB42-3A 8 714 432 500 8 714 432 505
The wall mounted condensing gas boiler is set at the fac-
tory for installation below 2000 feet (610 m) above sea
level.
6 720 641 933-57.1O
6 720 641 933-58.1O
6 720 641 933-79.1O