Technical service bulletinHeat Exchanger Cleaning

Bulletin Number: TBG-42 | Model: GB142 series boilers

Heat Exchanger Cleaning Procedure

Switch off the power supply of the heating system on the circuit breaker.

Set the main switch on the BC10 to “0” (Off).

Remove the casing.

Close the gas shut-off valve (see fig. 1, pos. 1).

Figure 1

Open

Closed

Loosen the union nut of the gas control valve (see fig. 2, pos. 1).

Figure 2

11

Remove the cable plug from the gas control valve (see fig. 3).

Figure 3

Remove both cable plugs [Fig.4, pos.1] from the fan unit.

11

Figure 4

Pull down on both retaining clips [Fig.5, pos.1] to open and remove the burner cover.

1. 1.1. 1.

Figure 5

1 of 3

Bulletin Number: TBG-42 | GB142 Heat Exchanger Cleaning Technical service bulletin

Data subject to change without notice | BTC 435002109 A | 07.2013 Buderus

Remove the burner gasket (see fig. 6, pos. 1).

Remove the gas/air distributor plate (see fig. 6, pos. 2).

Remove the orifice plate (only applies to Logamax plus GB142-24/30 and GB142-60) (see fig. 6, pos. 3). Note that the orifice plate of the GB142-60 has a different shape.

Remove the burner (see fig. 6, pos. 4).

1

2

3

4

1

2

3

4

Figure 6

Disconnect the hot surface ignitor and ionization electrode plugs.

Loosen the fastening screws [Fig.7, pos.1].

Pull the ground cable from the hot surface ignitor [Fig.7, pos.2].

Dismantle the mounting plate [Fig.7, pos.3].

1

1

3

2

41

1

3

2

4

Figure 7

Remove both the hot surface ignitor and the ionization electrode from heat exchanger [Fig.8].

Figure 8

Paint or spray Heat Exchanger with mineral oil

Re-assemble all parts in reverse order of disassembly.

WARNINGIt is important to inspect the rubber gaskets. Replace brittle, discolored, split or worn rubber gaskets.

Switch on the heating system using the main switch.

Press the “Chimney Sweep” button until the decimal point is displayed. Leave the boiler on for approx. 10 minutes.

Switch off the heating system using the main switch.

Dismantle the boiler again and flush the heat exchanger with water.

Pull the condensate trap from the condensate plate (fig. 9, pos. 1).

1 2

3

1 2

3

Figure 9

Pull the internal condensate bypass pipe (if installed) from the condensate trap (see fig. 9, pos. 2).

2 of 3

Bulletin Number: TBG-42 | GB142 Heat Exchanger Cleaning Technical service bulletin

Data subject to change without notice | BTC 435002109 A| 07.2013 Buderus

Bosch Thermotechnology Corp.50 Wentworth AveLondonderry, NH 03053Tel: (800) 283-3787Fax: (603) 965-7581www.buderus.us

Loosen the condensate trap from the connection (fig. 9, pos. 3) and remove it.

Use a bristle brush to clean the condensate trap.

Flush the condensate trap.

Open latches [Fig. 10, pos.1] on the condensate collector.

1 11 1

Figure 10

Remove the condensate collector.

Remove the baffle plate and clean it using compressed air [Fig. 11]. If necessary brush fins with a stiff nylon brush.

Figure 11

Check the condensate trap gasket for damage and replace it if necessary.

Fill the condensate trap with water before re-installing it.

Reassemble all parts in reverse order of disassembly.

NOTICEFor heavy build up, repeat procedure.

NOTICERecommended cleaning interval is every 2 years.

3 of 3