Viessmann Vitocrossal 300 CA3B Installation instructions

Field Disassembly and
Reassembly Instructions
Vitocrossal 300 CA3B
Single Fuel and Dual Fuel
Please file in Service Binder
For use by heating contractor
Product may not be exactly as illustrated.
Vitocrossal 300 CA3B
Single and Dual Fuel Series Boilers
This document is to be used where access for the
placement of the boiler is restricted and when height
reduction as described in the Installation Instructions has
been completed and further disassembly is still required.
IMPORTANT
Review the applicable boiler Installation
Instructions, Service Instructions and this Field
Disassembly and Reassembly Instructions prior to
proceeding with the further disassembly of the boiler.
5831 907 - 04 11/2018

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Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Safety, Service and Warranty Requirements
Safety
Please ensure that these instructions are read and understood before commencing installation. Failure to comply with
the instructions listed below and details printed in this manual can cause product/property damage, severe personal
injury, and/or loss of life. Ensure all requirements below are understood and fulfilled (including detailed information
found in manual subsections).
WARNING
Installers must follow local regulations with respect to
installation of carbon monoxide detectors. Follow the
Viessmann maintenance schedule of the boiler contained
in this manual.
Product documentation
Read all applicable documentation before commencing
installation. Store documentation near boiler in a
readily accessible location for reference in the future
by service personnel.
For a listing of applicable literature,
please see section entitled “Important
Regulatory and Safety Requirements”.
Warranty
Information contained in this and
related product documentation must
be read and followed. Failure to do
so renders the warranty null and void.
Licensed professional heating contractor
The installation, adjustment, service and maintenance
of this equipment must be performed by a licensed
professional heating contractor.
Please see section entitled
“Important Regulatory and Installation
Requirements”.
Contaminated air
Air contaminated by chemicals can cause by-products
in the combustion process, which are poisonous to
inhabitants and destructive to
Viessmann equipment.
For a listing of chemicals which
cannot be stored in or near the
boiler room, please see subsection
entitled “Mechanical room” in this
manual.
Advice to owner
Once the installation work is complete, the heating
contractor must familiarize the system operator/
ultimate owner with all equipment, as well as safety
precautions/requirements, shutdown procedure, and
the need for professional service annually before the
heating season begins.
Carbon monoxide
Improper installation, adjustment, service and/or
maintenance can cause flue products to flow into
living space. Flue products contain poisonous carbon
monoxide gas.
For information pertaining to the
proper installation, adjustment, service
and maintenance of this equipment to
avoid formation of carbon monoxide,
please see subsection entitled
“Mechanical room” and “Venting
requirements” in this manual.
Fresh air
This equipment requires fresh air for
safe operation and must be installed
ensuring provisions for adequate
combustion and ventilation air exist.
For information pertaining to the
fresh air requirements of this product,
please see subsection entitled
“Mechanical room” in this manual.
Equipment venting
Never operate boiler without an installed venting
system. An improper venting system can cause
carbon monoxide poisoning.
For information pertaining to
venting and chimney requirements,
please see section entitled “Venting
Connection”. All products of
combustion must be safely vented
to the outdoors.

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Safety, Service and Warranty Requirements (continued)
Safety
WARNING
Inhaling of fiberglass wool and/or ceramic fiber
materials is a possible cancer hazard. These materials
can also cause respiratory, skin and eye irritation.
Fiberglass wool and ceramic fiber materials
WARNING
Appliance materials of construction, products of
combustion and the fuel contain alumina, silica, heavy
metals, carbon monoxide, nitrogen oxides, aldehydes
and/or other toxic or harmful substances which can
cause serious injury or loss of life and which are
known to the State of California to cause cancer,
birth defects and other reproductive harm. Always
use proper safety clothing, respirators and equipment
when servicing or working nearby the appliance.
The state of California has listed the airborne fibers of
these materials as a possible cancer hazard through
inhalation. When handling these materials, special care
must be applied.
First aid measures
- If eye contact occurs, flush eyes with water to remove
dust. If symptoms persist, seek medical attention.
- If skin contact occurs, wash affected areas gently
with soap and warm water after handling.
Suppliers of fiberglass wool products recommend the
following precautions be taken when handling these
materials:
- Avoid breathing fiberglass dust and contact with
skin and eyes.
- Use NIOSH approved dust/mist respirator.
- Wear long-sleeved, loose fitting clothing, gloves
and eye protection.
- Wash work clothes separately from other clothing.
Rinse washer thoroughly.
- Operations such as sawing, blowing, tear-out and
spraying may generate airborne fiber concentration
requiring additional protection.
Codes
The installation of this unit shall be in accordance with
local codes. In the absence of local codes, use:
CAN/CSA-B149.1 or .2 Installation Codes for Gas Burning
Appliances for Canada. For U.S. installations, use the
National Fuel Gas Code ANSI Z223.1. Always use latest
editions of codes.
In Canada all electrical wiring is to be done in accordance
with the latest edition of CSA C22.1 Part 1 and/or local
codes. In the U.S., use the National Electrical Code ANSI/
NFPA 70.
The heating contractor must also comply with the Standard
for Controls and Safety Devices for Automatically Fired
Boilers, ANSI/ASME CSD-1 where required by the authority
having jurisdiction.
Mechanical room
Viessmann recommends installation of an additional
electrical disconnect switch and a fuel shut-off valve (if
possible) outside the mechanical room or enclosed area
of installation.
The maximum room temperature of the mechanical room
where the boiler is located must not exceed 104°F (40°C).
Suppliers of ceramic fiber products recommend the
following first aid measures:
- Respiratory tract (nose and throat) irritation:
If respiratory tract irritation develops, move the
person to a dust free location.
- Eye irritation: If eyes become irritated, flush immediately
with large amounts of lukewarm water for at least 15
minutes. Eyelids should be held away from the eyeball
to ensure thorough rinsing. Do not rub eyes.
- Skin irritation: If skin becomes irritated, remove soiled
clothing. Do not rub or scratch exposed skin.
Wash area of contact thoroughly with soap and cold
water (as warm or hot water may worsen the irritation).
Using a skin cream or lotion after washing may be
helpful.
- Gastrointestinal irritation: If gastrointestinal tract
irritation develops, move the person to a dust free
environment.

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Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Table of Contents
Safety
Service Equipment
Specifications
Disassembly
Page
Safety, Installation and Warranty Requirements..............2
Product documentation...........................................2
Warranty...............................................................2
Licensed professional heating contractor...................2
Contaminated air...................................................2
Advice to owner....................................................2
Carbon monoxide...................................................2
Fresh air...............................................................2
Equipment venting.................................................2
Fiberglass wool and ceramic fiber materials...............3
First aid measures .................................................3
Codes..................................................................3
Mechanical room...................................................3
Vitocrossal 300 .........................................................6
Assembly kit.........................................................6
Service equipment.................................................6
Cleaning supplies ..................................................6
Testing/analysis equipment.....................................6
Lifting the boiler....................................................6
Compact Cylinder Radiant Burner (CA3B models 2.5 to
3.0 SF) .....................................................................7
Compact Cylinder Radiant Burner (CA3B models 3.5 to
6.0 SF & 2.5 to 6.0 DF)..............................................8
Boiler Supply and Return Headers.................................9
Gas Pipes ................................................................10
Heat Exchangers and Base (Single Fuel) ......................11
Heat Exchangers and Base (Dual Fuel).........................12
Base and Control Panel .............................................13
Boiler Heat Exchanger Sections ..................................14
Removing the Boiler Panels........................................15
Removal of the Upper Frame Profiles ..........................16
Disconnecting the Burner Assembly............................17
Removing the Temperature Limit Switches ..................18
Removing Cable Guide and Cable Trays.......................19
Removing the Frame Posts ........................................20
Removing the Supply and Return Headers (Single Fuel)...21
Removing the Supply and Return Headers (Dual Fuel) ...22
Removing the Gas Lines and Thermal Insulation ...........23
Removal of the Boiler Heat Exchanger Sections............24
Transporting the Lower Frame and Control Panel..........25

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Table of Contents
Reassembly Installing the Sealing Cord .........................................26
Installing the Boiler Heat Exchanger Sections ...............27
Installing the Burner Assembly ...................................28
Installing the Gas Lines and Thermal Insulation.............30
Installing the Supply and Return Header (Single Fuel) ....31
Installing the Supply and Return Header (Dual Fuel) ......32
Installing the Frame Posts..........................................33
Installing the Cable Guide and Cable Trays ..................34
Installing the Temperature Limit Switches....................35
Installation of the Upper Frame Profiles .......................36
Installing the Boiler Panels .........................................37
Page

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Vitocrossal 300
Service Equipment
Assembly kit for use with;
CA3B 2.5/3.0 Dual Fuel ............................ Part # 7551301
CA3B 2.5/3.0 Single Fuel .......................... Part # 7551296
CA3B 3.5 Dual Fuel .................................. Part # 7551302
CA3B 3.5 Single Fuel................................ Part # 7551297
CA3B 4.0 Dual Fuel .................................. Part # 7551303
CA3B 4.0 Single Fuel................................ Part # 7551298
CA3B 5.0 Dual Fuel .................................. Part # 7551304
CA3B 5.0 Single Fuel................................ Part # 7551299
CA3B 6.0 Dual Fuel. ................................. Part # 7551305
CA3B 6.0 Single Fuel................................ Part # 7551300
Tools
Assortment of flathead and Phillips screwdrivers
Pipe wrenches
Open-ended metric wrenches
Pipe sealant
Assortment of metric Hex keys
Flashlight
Approved leak detection fluid for natural gas and
propane gas
Pressure gauge (2.3 ”w.c. to 3.5 “w.c.)
Crane or gantry
Nitrogen or air compressor
Cleaning supplies
Plastic hand brush
Cleaning/service brush
Vacuum cleaner
Clean rags
Testing/analysis equipment
(use only calibrated equipment)
Flue gas analyzer
Multimeter to measure 0-120VAC, 0-20 amps AC
and 0-100 microamps DC
Manometer (0 to 56 “w.c. or 2 psig)
din. NPT male to ¼ in. barb adaptor fitting
Service equipment
It is essential to use appropriate lifting devices
certified of lifting to a minimum of the boiler
weight.
WARNING
If flue gas connection is damaged leakage may occur.
Do not lift boiler at the flue gas connection.
The lifting should be performed by a trained technician.
When lifting, take sufficient safety measures and proceed
with great care. Refer to the lifting diagram. All lifting
equipment is field supplied.
Lifting the boiler

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Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Compact Cylinder Radiant Burner (CA3B models 2.5 to 3.0 SF)
Specifications
Burner Model 1250 Compact 1500 Compact
a in. (mm) 27b(699) 27b(699)
b in. (mm) 33b(845) 33b(845)
c in. (mm) 21c(550) 21c(550)
Weight SF lbs. (kg) 176 (80) 176 (80)
Burner Combinations
CA3B Boilers Burner input MBH
Section 1 (Lead) Section 2 (Lag 1) Section 3 (Lag 2)
2.5 1250 Compact 1250 Compact --
3.0 1500 Compact 1500 Compact --
Note: dimensional tolerance of ain. (5 mm)

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Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Specifications
Compact Cylinder Radiant Burner (CA3B models 3.5 to 6.0 SF & 2.5 to 6.0 DF)
Burner Model 1250 1500 2000
a in. (mm) 29b(749) 29b(749) 33 (838)
b in. (mm) 33a(843) 33a(843) 34b(878)
c in. (mm) 25b(647) 25b(647) 25c(657)
Weight SF lbs. (kg) -- 100 (45) 110 (50)
Weight DF lbs. (kg) 100 (45) 100 (45) 110 (50)
Burner Combinations
CA3B Boilers Burner input MBH
Section 1 (Lead) Section 2 (Lag 1) Section 3 (Lag 2)
2.5 (DF only) 1250 1250 --
3.0 (DF only) 1500 1500 --
3.5 1500 2000 --
4.0 2000 2000 --
5.0 1500 1500 2000
6.0 2000 2000 2000
Note: dimensional tolerance of ain. (5 mm)

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Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Specifications
Boiler Supply and Return Headers
Boiler Supply Headers
Boiler Return Headers
2.5 to 5.0 Single/Dual Fuel
6.0 Single/Dual Fuel
2.5 to 5.0 Single/Dual Fuel
6.0 Single/Dual Fuel
Boiler Model 2.5 and 3.0 SF 3.5 and 4.0 SF
2.5 and 4.0 DF
5.0 SF
5.0 DF
6.0 SF
6.0 DF
a in. (mm) 11 (281) 11 (281) 11 (281) 12b(317)
b in. (mm) 76 (1932) 81b(2068) 113a(2876) 112c(2865)
c in. (mm) 9 (229) 9 (229) 9 (229) 12b(317)
Weight lbs. (kg) 102 (46) 106 (48) 148 (67) 183 (83)
Boiler Model 2.5 and 3.0 SF 3.5 and 4.0 SF
2.5 and 4.0 DF
5.0 SF
5.0 DF
6.0 SF
6.0 DF
a in. (mm) 11 (281) 11 (281) 11 (281) 12b(316)
b in. (mm) 59b(1512) 66b(1686) 98b (2505) 98 (2492)
c in. (mm) 9 (229) 9 (229) 9 (229) 12a(315)
Weight lbs. (kg) 86 (39) 93 (42) 132 (60) 160 (73)
Boiler Supply Headers
Boiler Return Headers
Note: dimensional tolerance of ain. (5 mm)
Note: dimensional tolerance of ain. (5 mm)

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Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Gas Pipes
Specifications
Gas Pipes
2.5 to 6.0 Single Fuel
2.5 to 4.0 Dual Fuel
5.0 and 6.0 Dual Fuel
Boiler Model 2.5 and 3.0 SF 3.5 and 4.0 SF 5.0 and 6.0 SF
a in. (mm) 6a(160) 6a(160) 6c(171)
b in. (mm) 53b(1361) 59b(1511) 91c(2331)
c in. (mm) 4a(111) 6b(164) 6c(171)
Weight lbs. (kg) 30 (14) 50 (23) 86 (39)
Boiler Model 2.5 to 4.0 DF 5.0 and 6.0 DF
a in. (mm) 59b(1512) 92 (2338)
b in. (mm) 26a (666) 34a(872)
c in. (mm) 25b(647) 33a(843)
d in. (mm) 21c(554) 21c(554)
e in. (mm) 8c(225) 8c(225)
Weight lbs. (kg) 198 (90) 214 (97)
Gas Pipes
Note: dimensional tolerance of ain. (5 mm)

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Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Specifications
Heat Exchangers and Base (Single Fuel)
CA3B Boilers Section 1 (Lead) Section 2 (Lag 1) Section 3 (Lag 2)
2.5 1.25/1.5 Compact 1.25/1.5 Compact --
3.0 1.25/1.5 Compact 1.25/1.5 Compact --
3.5 1.5 2.0 --
4.0 2.0 2.0 --
5.0 1.5 1.5 2.0
6.0 2.0 2.0 2.0
CA3B Boilers Dimensions 1.25/1.5 Compact 1.5 2.0
a in. (mm) 53a(1354) 58e(1483) 58e(1483)
b in. (mm) 51¾ (1313) 56 (1444) 56 (1444)
c in. (mm) 48¾ (1238) 53 (1369) 53 (1369)
d in. (mm) 30a(767) 34¾ (882) 35b(900)
e in. (mm) 25¾ (654) 27 (709) 29f(751)
f in. (mm) 23f(600) 29f(751) 27b(700)
g in. (mm) 8e(213) 8e(213) 8e(213)
Single Fuel
Note: dimensional tolerance of ain. (5 mm)
Lead Lag 1 Lag 2

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Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Heat Exchangers and Base (Dual Fuel)
Specifications
CA3B Boilers Section 1 (Lead) Section 2 (Lag 1) Section 3 (Lag 2)
2.5 1.5 1.5 --
3.0 1.5 1.5 --
3.5 1.5 2.0 --
4.0 2.0 2.0 --
5.0 1.5 1.5 2.0
6.0 2.0 2.0 2.0
CA3B Boilers Dimensions 1.5 2.0
a in. (mm) 58e(1483) 58e(1483)
b in. (mm) 56 (1444) 56 (1444)
c in. (mm) 53 (1369) 53 (1369)
d in. (mm) 34¾ (882) 35b(900)
e in. (mm) 27 (709) 29f(751)
f in. (mm) 27b(700) 27b(700)
g in. (mm) 8e(213) 8e(213)
Dual Fuel
Note: dimensional tolerance of ain. (5 mm)
Lead Lag 1 Lag 2

5831 907 - 04
Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Base and Control Panel
Specifications
Boiler Model 2.5 and 3.0 SF 3.5 and 4.0 SF 2.5 to 4.0 DF 5.0 and 6.0 SF
5.0 and 6.0 DF
a in. (mm) 85c(2178) 96b(2453) 96b(2453) 133 (3376)
b in. (mm) 31b(800) 36c(936) 36c(936) 36c(936)
c in. (mm) 14 (357) 14 (357) 14 (357) 14 (357)
d in. (mm) 64 (1630) 64 (1630) -- --
e in. (mm) -- -- 77c(1973) 77c(1973)
f in. (mm) 88b(2246) 99a(2520) 99a(2520) 135b(3444)
Weight
of Bases with
out control
lbs. (kg) 545 (247) 662 (300) 662 (300) 924 (420)
Weight of
Controls with
out base
lbs. (kg) 121 (55) 125 (57) 150 (68) 176 (80)
Note: dimensional tolerance of ain. (5 mm)
Base and control panel
9.5" not including the flue
REMOVEABLE AS
PER MANUFACTURER

5831 907 - 04
Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Boiler Heat Exchanger Sections
Specifications
Boiler
Section
1.5 2.0
a in. (mm) 38a(970) 38a(970)
b in. (mm) 38b(978) 38b(978)
c in. (mm) 58a(1482) 58a(1482)
Weight lbs. (kg) 930 (422) 1035 (470)
CA3B
Boilers
Section 1
(Lead)
Section 2
(Lag 1)
Section 3
(Lag 2)
2.5 1.5 1.5 --
3.0 1.5 1.5 --
3.5 1.5 2.0 --
4.0 2.0 2.0 --
5.0 1.5 1.5 2.0
6.0 2.0 2.0 2.0
Boiler
Section
1.25/1.5
Compact
1.5 2.0
a in. (mm) 30a(767) 38a(970) 38a(970)
b in. (mm) 28a(717) 38b(978) 38b(978)
c in. (mm) 53a(1351) 58a(1482) 58a(1482)
Weight lbs. (kg) 730 (331) 930 (422) 1035 (470)
CA3B
Boilers
Section 1
(Lead)
Section 2
(Lag 1)
Section 3
(Lag 2)
2.5 1.25/1.5 Compact 1.25/1.5 Compact --
3.0 1.25/1.5 Compact 1.25/1.5 Compact --
3.5 1.5 2.0 --
4.0 2.0 2.0 --
5.0 1.5 1.5 2.0
6.0 2.0 2.0 2.0
Dual Fuel
Single Fuel
Note: dimensional tolerance of ain. (5 mm)
Note: dimensional tolerance of ain. (5 mm)
24" diameter drum

5831 907 - 04
Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Disassembly
Removing the Boiler Panels
1. Remove the screws from the right side of the top
panels.
2. Lift and remove the top right-side panels.
3. Slide the top panels toward the right side and
remove.
4. Lift and remove the top left side panels.
5. Lift and remove the bottom left side panels.
6. Tilt forward, lift and remove lower front panel.
7. Remove the screws from the lower front cover plate
and remove plate.
8. Lift and remove the top front panel.
9. Remove the screws from the top front cover plate
and remove plate.
10. Protect jacketing from damage while they are set
aside.
Note: The Vitocrossal 300, CA3B having two boiler
heat exchanger sections will have reduced number
of disassembly steps compared to a
Vitocrossal 300, CA3B having three boiler heat
exchanger sections.

5831 907 - 04
Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Disassembly
Removal of the Upper Frame Profiles
1. Remove the lower M8 nut and bolt from each side of
the lower portion of the upper frame profiles.
2. Lift all upper parts of the frame and set aside.

5831 907 - 04
Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Disconnecting the Burner Assembly
Disassembly
1. Disconnect the burner gas line.
Note: Do not lose gasket.
2. Disconnect plugs 145, 41, 53 and 40 on the
burner control unit.
3. Remove sensors 15A/B and 3A/B from the sensor
wells.
4. Disconnect wiring and remove electrode block.
5. Remove the 6 nuts around the burner mounting
plate.
6. Remove upper burner section.
Note: Repeat the steps listed above for all remaining
burners installed on the boiler.

5831 907 - 04
Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Removing the Temperature Limit Switches
Legend
ACapillary bulb
BSupply water temperature limit switch
CFlue gas temperature limit switch
1. Remove the screw holding the limit switches B
and C.
2. Remove limit switches Band Cfrom wells.
3. Label Bsupply water temperature limit switch
and Cflue gas temperature limit switch.
4. Disconnect wiring from limit switches Band
Cand set both limit switches aside.
5. Remove cable ties from the cable trays and wiring.
Disassembly

5831 907 - 04
Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Removing Cable Guide and Cable Trays
1. Release the cables from the cable guide and
remove the cable guide at the front and rear.
2. Remove the screws and the frame crossbar on both
sides.
3. Using an allen key remove the screws and remove
the cable tray segments.
Disassembly

5831 907 - 04
Vitocrossal 300, CA3B Series 2.5 to 6.0 Technical Data
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Removing the Frame Posts
1. Remove screws and lock washers A8.4. Remove spacer
bracket from the corner rails.
2. Release the mounting brackets on the boiler sections by
removing the hexagon bolts, washers and nuts.
3. Remove the corner posts with washers 10.5 and M10
nuts to the base frame. Remove the center posts with
washers 10.5 and M10 nuts to the base frame.
Disassembly