Buderus GB142 Series User Manual

Technical service bulletin
Heat Exchanger Replacement
Bulletin Number: TBG-35 | Model: GB142 series boilers
Heat Exchanger Replacement Procedure
 Remove the cable plug from the gas control valve.
Figure 1
 Remove both cable plugs [Fig.2, pos.1] from the fan unit.
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1
Figure 2
 Pull down on both retaining clips [Fig.3, pos.1] to open and
remove the burner cover.
1.
1.
1.
1.
Figure 3
 Remove the burner [Fig.4, pos.1].
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1
Figure 4
 Disconnect the supply [Fig.5, pos.1] and return [Fig.5, pos.2]
sensors.
CAUTION: electrical short circuit
To prevent mix-ups, the supply sensor is marked by a
red sleeve on the side of the cable harness.
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2
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2
Figure 5
 Disconnect the safety sensor [Fig.6, pos.1].
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Figure 6
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Buderus GB142 Series Specifications

General

Modulation	Yes
Installation Type	Wall-mounted
Fuel Type	Natural Gas
Modulation Ratio	1:5
Ignition Type	Electronic

Summary

Heat Exchanger Replacement Procedure

Disconnect Gas Control Valve Plug

Remove the cable plug from the gas control valve for the heat exchanger replacement.

Disconnect Fan Unit Plugs

Remove both cable plugs from the fan unit as part of the procedure.

Remove Burner Cover

Pull down retaining clips to open and remove the burner cover.

Remove Burner Assembly

Remove the burner assembly from the appliance.

Disconnect Supply and Return Sensors

Disconnect supply and return sensors, noting the marked supply sensor.

Disconnect Safety Sensor

Disconnect the safety sensor from the appliance.

Disconnect Ignitor and Electrode Plugs

Disconnect the hot surface ignitor and ionization electrode plugs.

Remove Mounting Plate

Loosen fastening screws and dismantle the mounting plate.

Remove Ignitor and Electrode

Remove the hot surface ignitor and ionization electrode from the heat exchanger.

Access Condensate Collector

Open latches on the condensate collector to access components.

Remove Condensate Collector

Remove the condensate collector from the appliance.

Dismantle Tension Spring

Dismantle the tension spring between the supply pipe and heat exchanger.

Disconnect Supply Pipe

Loosen a nut and pull the supply pipe from the heat exchanger.

Remove Air and Flue Connections

Pull upwards combustion air supply and flue gas exhaust connections.

Remove Flue Gas Adapter

Loosen screws and remove the flue gas adapter from the appliance.

Remove Heat Exchanger

Pull the heat exchanger forward and push it upwards.

Prepare Flue Gas Collector

Remove the flue gas collector and its oval seal from the old heat exchanger.

Apply Sealant to New Oval Seal

Apply silicon to both sides of the new oval seal for the flue gas collector.

Reassemble Flue Gas Collector

Reassemble the flue gas collector with the new oval seal to the new heat exchanger.

Install New Condensate Seal

Install the new seal for the condensate collector and check placement.

Final Assembly

Install the new heat exchanger and all other parts in reverse order of disassembly.