Bosch GB125 Manuel utilisateur

Product Information Notice

Models: GB125/35

Subject: Field Action - Safety Rework Instructions

Data subject to change without notice | BTC 410004103 C | 01.2020 Bosch Thermotechnology Corp.

All work must be performed by a licensed or qualiﬁed

contractor.

Summary

The GB125/35 oil-ﬁred boiler from Buderus may accumulate

combustion debris under certain conditions, resulting in the siphon

becoming clogged. A clogged siphon can block the ﬂue pipe and

consequently may lead to increased formation of carbon monoxide

(CO) in the boiler. If the boiler also has an opening into the

installation room, CO can escape, posing a safety risk.

To minimize the safety risk Bosch is initiating a ﬁeld action for all

installed GB125/35 boilers.

The following actions are required for the GB125/35 model:

The burner control must be replaced with an upgraded

version (provided by Bosch free of charge).

The existing condensate siphon must be replaced with a new

one (provided by Bosch free of charge).

Replace the heat exchanger clean out cover seal if necessary

(provided by Bosch free of charge).

A labor allowance of up to $300 is available for carrying out this

ﬁeld action (a separate claim form is available and must be used for

labor reimbursement).

If you have any further questions, please contact us directly on

1-800-323-1943 or at [email protected] and reference

“GB125/35 Field Action” in the subject line.

Relevant Part Numbers

Description Part Number

Burner Control Unit 8738806487

Condensate Siphon (w/ ﬂoat) 7747020450

12 mm sealing cord (white)* w/silicone 8718578900

8 mm sealing cord (blue)* w/silicone 8718579535

* The speciﬁc sealing cord supplied depends on the date of production of

the boiler. We will supply the correct cord to you.

Required Field Action

Burner Control (LMO) Replacement

1. Switch off the boiler and remove the front cover (Fig. 1).

Figure 1

2. There is a clip located on the bottom and the top of the

Burner Control (LMO), which needs to be released for

disassembly. To remove use a ﬂat screwdriver, place it under

the clip and push it upwards to unlock the clip (Fig. 2 and Fig.

3). Afterwards you can remove the LMO (Fig. 4).

Figure 2

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Data subject to change without notice | BTC 410004103 C | 01.2020

GB125/35 Field Action - Safety Rework Instructions Product Information Notice

Bosch Thermotechnology Corp.

Figure 3

Figure 4

3. To install a new LMO, put it on the mounting plate and press

it on until you feel it locking.

4. Now, you can switch on the boiler again. If an error message

appears after switching-on, press the round button on the

front side of the LMO (Fig. 5) for approximately 1 second (but

do not press longer than 5 seconds).

Figure 5

Required Field Action - Condensate Inspection

CAUTION:

Condensate is corrosive. Wear gloves and

avoid contact with skin and clothing.

1. Switch off the boiler then remove the existing siphon. Pour

the condensate out of the siphon. Remove the existing ﬂoat,

inspect it, and take a photograph of it (Fig. 6, Item A).

Figure 6

Undo this

fitting when

replacing

the siphon

2. Install the supplied new siphon assembly into the boiler.

Required Field Action - Clean-Out Cover Inspection

1. Switch oﬀ the boiler and then remove the boiler cover (Fig. 9).

Figure 9

2. Push the thermal insulation up under the boiler cover or fold it

down (Fig. 10).

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Bosch Thermotechnology Corp.

Product Information Notice GB125/35 Field Action - Safety Rework Instructions

Data subject to change without notice | BTC 410004103 C | 01.2020

Figure 10

3. Expose the clean-out cover by pulling out the remaining thermal

insulation (Fig. 11).

Figure 11

4. Visually check whether the clean-out cover has any leaks

(Fig. 12). The cover must be ﬂush with all the edges and

the seal must not be visible. When you are satisﬁed with

the tightness of the cleaning cover, reposition the thermal

insulation correctly. Then close the boiler casing. After this,

you can switch the boiler on again.

Figure 12

5. If the cover seal is not OK (Fig. 13), it must be replaced.

Figure 13

BAD COVER SEAL EXAMPLES

6. You will need the old clean-out cover, a new seal, a tube of

silicone adhesive. The individual steps are explained on the

following pages.

Ensure the correct combination of components is used.

This depends on the version of the cleaning cover.

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Data subject to change without notice | BTC 410004103 C | 01.2020

GB125/35 Field Action - Safety Rework Instructions Product Information Notice

Bosch Thermotechnology Corp.

Figure 14

Stainless steel cover w. 12 mm sealing cord (light blue)

For boilers made prior to March 2011

Aluminum cover w. 8 mm sealing cord (blue)

For boilers made March 2011 and after

The following instructions apply to both versions.

7. Remove the cleaning cover, remove excess adhesive and

ensure that the cover is free of dust and grease (Fig. 15).

Figure 15

You can preform the new seal to ﬁt at this stage by

gently pulling it apart (Fig. 16) and then pressing both

ends of the white joining piece together with your

ﬁngers (Fig. 17 and Fig. 18). Provisionally insert the seal

into the groove to test it, ensuring that it lies cleanly in

the groove (Fig. 19).

Figure 16

Figure 17

Figure 18

Figure 19

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GB125/35 Field Action - Safety Rework Instructions Product Information Notice

Data subject to change without notice | BTC 410004103 C | 01.2020 Bosch Thermotechnology Corp.

Bosch Thermotechnology Corp.

65 Grove Street

Watertown, MA 02472

Tel: (800) 323-1943

Email: [email protected]

www.boschheatingandcooling.com

8. Now apply silicone to the groove of the clean-out cover. The

aim is to insert a 1-2 mm wide silicone bead all the way round

the outer edge of the cover groove (Fig. 20-22).

It is important that the groove is not completely ﬁlled with

silicone. The base of the groove should still be half free.

Applying silicone requires a certain degree of precision,

so test the silicone cartridge on a piece of paper before-

hand.

Figure 20

Figure 21

2 mm

Figure 22

9. Insert the seal into the groove and press it ﬁrmly right down to

the bottom of the groove (Fig. 23).

Figure 23

10. Ensure that the seam or joint of the new seal is centered on

one of the long sides of the inside of the cover (Fig. 24) and

that the seal is ﬂush with the edges of the groove (Fig. 25).

Figure 24

Figure 25

11. Replace the clean-out cover and secure it with the clips. After

this, perform another visual check (Fig. 12) to ensure that

the cover sits ﬂush and the seal is not visible at any point,

otherwise the procedure must be corrected. Finally, put the

thermal insulation back in the correct position. Close the

boiler casing. After this, you can start the boiler up again.

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