Bosch GB125 User manual

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
A
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
1
2
3. Expose the clean-out cover by pulling out the remaining thermal
insulation (Fig. 11).
Figure 11
3
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: [phone]
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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