Strebel S-CBX 85 Installation instructions

STREBEL
S-CBX Cascade Kits
Models 85 - 105 - 125 - 155
Installation & Operating Manual
2 x 85 up to 6 x 155
Please read and understand before commencing installation and leave the manual with the customer for future reference.
2019-05-01 v1

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Contents
1. INTRODUCTION........................................................................................................................................4
2. INSTALLATION PROCEDURE CASCADE CONFIGURATION..............................................................5
3. DETERMINE POWER REQUIRED FOR THE CASCADE CONFIGURATION........................................6
4. CALCULATE DIMENSIONS AND SPACE OF CASCADE CONFIGURATION ......................................8
5. EXPLANATION OF PARTS AND GROUPS ..........................................................................................11
6. CONNECTING SETS ..............................................................................................................................12
7. HYDRAULIC AND GAS HEADER GROUP............................................................................................13
7.1 Headers...........................................................................................................................................13
7.2 Support beam and support brackets...............................................................................................13
7.3 Headers and connecting sets..........................................................................................................14
8. MOUNTING THE FRAME .......................................................................................................................15
8.1 Frame elements ..............................................................................................................................15
8.2 Procedure for mounting the frame ..................................................................................................16
9. MOUNTING THE GAS HEADER ............................................................................................................17
10. MOUNTING THE BOILERS ON THE FRAME........................................................................................18
11. MOUNTING THE HYDRAULIC GROUP AND THE CONNECTING SETS............................................19
12. MOUNTING THE LOW LOSS HEADERS ..............................................................................................20
13. DETERMINE MANAGING AND DEPENDING BOILERS ......................................................................21
14. COMPLETE THE MECHANICAL INSTALLATION................................................................................21
15. MOUNT THE FLUE GAS AND AIR SUPPLY SYSTEMS.......................................................................22
15.1 Individual flue systems....................................................................................................................22
15.2 Common flue system.......................................................................................................................22
16. SET PARAMETERS................................................................................................................................23
17. COMMISSIONING THE CASCADE CONFIGURATION ........................................................................23
18. ACCESSORIES.......................................................................................................................................24
19. REFERENCES.........................................................................................................................................24
19.1 List of figures...................................................................................................................................24
19.2 List of tables ....................................................................................................................................24
20. APPENDIX A –CASCADE PARTS........................................................................................................25

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1. Introduction
This cascade manual is intended for the wall-hung high efficiency central heating boilers from the S-CBX boiler
series as manufactured by Strebel Ltd
The boilers can be combined in one cascade configuration. This ensures that the required power can always be
achieved. Since several boilers are combined this allows for a deeper modulation range and for more precisely
achieving the required level.
Furthermore, the cascade configuration offers an increased reliability: should one boiler go into error, the
cascade configuration will continue to operate.
Strebel Ltd can supply standard cascade systems with mounting frame, piping and low loss headers for up to six
boilers depending on the range. Larger amounts of boilers in a cascade combination are possible but require a
dedicated system which must be designed separately.
The software allows for combining of up to 16 S-CBX boilers in a single cascade installation.
This document will offer you a general procedure for the complete installation of a cascade configuration.
For specific details regarding connections, parameters, venting, etc. see the Installation & Service Manual of the
boilers.
Figure 1.1 Two S-CBX boiler cascade configuration.

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2. Installation Procedure Cascade Configuration
In order to completely install a cascade configuration of two or more boilers, the following procedure should be
observed:
1. Calculate the total required amount of power for the cascade configuration and determine the
number of boilers necessary in the cascade configuration to achieve the required power.
This is described in detail in chapter 3.
2. Determine the dimensions of the cascade set and the required space at the planned location.
This is described in detail in chapter 4.
3. Mount the frame.
This is described in detail in chapter 8.
4. Mount the gas header.
This is described in detail in chapter 9.
5. Mount the boilers on the frame.
This is described in detail in chapter 10.
6. Mount the hydraulic group and the connecting sets.
This is described in detail in chapter 11.
7. Mount the low loss header.
This is described in detail in chapter 12.
8. Determine which boiler is managing and which are depending.
This is described in detail in chapter 13.
9. Complete the mechanical installation of the cascade configuration.
This is discussed in chapter 14.
10. Mount the flue gas and air supply systems.
This is discussed in chapter 15.
11. Set the parameters in the software by means of the controller of each boiler.
This is discussed in chapter 16.
12. Commission the cascade installation.
This is discussed in chapter 17.

6
3. Determine Power Required for the Cascade Configuration
The first step in the installation procedure for the cascade configuration is to determine the total power required
for the cascade configuration. This power is calculated based on the size of the room(s) to be heated and other
relevant variables. If the required power in kW is known, consult
Table 3.1 (below) in order to determine which combination of boilers can be applied to achieve the required
power.
Total
Power *
S-CBX 85
S-CBX 105
S-CBX 125
S-CBX 155
Total Number
of Boilers
170
2
2
187
1
1
2
204
2
2
210
1
1
2
227
1
1
2
236
1
1
2
249
2
2
253
1
1
2
255
3
3
272
2
1
3
276
1
1
2
289
1
2
3
295
2
1
3
302
2
2
305
3
3
312
1
1
1
3
321
2
1
3
328
2
1
3
335
1
2
3
338
1
1
1
3
340
4
4
351
1
2
3
355
2
1
3
357
3
1
4
361
1
1
1
3
374
3
3
374
2
2
4
378
1
1
1
3
380
3
1
4
387
1
2
3
391
1
3
4
397
2
1
1
4
400
2
1
3
404
1
2
3
406
3
1
4
407
4
4
413
1
2
1
4
420
2
2
4
423
2
1
1
4
426
5
5
427
1
2
3
430
3
1
4

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Total
Power *
S-CBX 85
S-CBX 105
S-CBX 125
S-CBX 155
Total Number
of Boilers
436
1
1
2
4
440
1
2
1
4
446
2
1
1
4
453
3
3
453
2
2
4
456
3
1
4
459
1
3
4
472
2
2
4
476
1
3
4
479
2
1
1
4
486
1
2
1
4
489
1
1
2
4
499
4
4
502
1
2
1
4
506
2
2
4
511
6
6
512
1
1
2
4
525
3
1
4
529
1
1
2
4
538
1
3
4
551
2
2
4
555
1
3
4
578
1
3
4
604
4
4
624
5
5
650
4
1
5
676
3
2
5
702
2
3
5
729
1
4
5
748
6
6
755
5
5
775
5
1
6
801
4
2
6
827
3
3
6
853
2
4
6
880
1
5
6
906
6
6
* Figures in this column represent the nominal output in kW at 50°C / 30°C
Table 3.1 Cascade power calculation table based on S-CBX boilers.
EXAMPLES
1) In case the required power is calculated at 275 kW, the table will show you that the required cascade
type and that the cascade configuration should have 2 boilers: one S-CBX 125 boiler and one S-CBX
155 boiler.
2) In case the required power is calculated at 440 kW, the table will show you that the required cascade
type and that the cascade configuration should have 4 boilers: one S-CBX 85 boiler, two S-CBX 105
boilers and one S-CBX 155 boiler.

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4. Calculate Dimensions and Space of Cascade Configuration
In this chapter is explained how to determine the dimensions of the cascade configuration and how much space
is required in the room where the cascade configuration will be installed.
Figure 4.1 Dimensions front view
L2 (length incl. low loss header)
L1 (length) )frame)
EHS.T0200.5050

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Figure 4.2 Dimensions: Side views
After you have determined which cascade configuration will be applied and therefore how many boilers must be
combined in the cascade configuration, the next step is to determine the total dimensions of the cascade
configuration and the space required for the cascade configuration.
Figure 4.1 and Figure 4.2 show a schematic representation of a cascade configuration. The dimensional
references in this figure (L1-L3, H1-H3, D1-D3, A, B) correspond with the dimensional references in the tables
below.
EXAMPLES
In case a cascade configuration for 275 kW is required, which will exist of 2 boilers, refer to Table 4.1 for the
dimensions of the cascade configuration. The table shows that frame length for this configuration is 1030 mm
and the total length including the low loss header is 1428 mm.
In case a cascade configuration for 440 kW is required, which will exist of 4 boilers, refer to Table 4.2 for the
dimensions of the cascade configuration. The table shows that frame length for this configuration is 2010 mm
and the total length including the low loss header is 2408 mm.
All these dimensions have to be taken into account when determining the space required for placing the
cascade configuration.
EHS.T0200.5050

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Number of Boilers
(up to 360 kW)
2 Boilers
3 Boilers
4 Boilers
L1 (length frame)
1030
1520
2010
L2 (total length incl. header)
1428
1918
2408
L3 (length low loss header)
422
422
422
H1 (height gas)
308
308
308
H2 (height header coupling)
248
248
248
H3 (height couplings)
350
350
350
D1 (header connection size)
DN 65 PN6 (2½ “)
DN 65 PN6 (2½ “)
DN 65 PN6 (2½ “)
D2 (header connection size)
DN 65 PN6 (2½ “)
DN 65 PN6 (2½ “)
DN 65 PN6 (2½ “)
D3 (gas connection size)
R 2”
R 2”
R 2”
A (gas)
253
253
253
B (headers)
459
459
459
Table 4.1 Dimensions S-CBX cascade up to 360 kW.
Number of Boilers
(360 up to 540 kW)
3 Boilers
4 Boilers
L1 (length frame)
1520
2010
L2 (total length incl. header)
1938
2473
L3 (length low loss header)
487
487
H1 (height gas)
308
308
H2 (height header coupling)
257
257
H3 (height couplings)
380
380
D1 (header connection size)
DN 80 PN6 (3 “)
DN 80 PN6 (3 “)
D2 (header connection size)
DN 80 PN6 (3 “)
DN 80 PN6 (3 “)
D3 (gas connection size)
R 2”
R 2”
A (gas)
253
253
B (headers)
466
466
Table 4.2 Dimensions S-CBX cascade 360 up to 540 kW.
Number of Boilers
(540 to 930 kW)
4 Boilers
5 Boilers
6 Boilers
L1 (length frame)
2010
2500
2990
L2 (total length incl. header)
2614
3104
3594
L3 (length low loss header)
628
628
628
H1 (height gas)
327
327
327
H2 (height header coupling)
272
272
272
H3 (height couplings)
420
420
420
D1 (header connection size)
DN 100 PN6 (4 “)
DN 100 PN6 (4 “)
DN 100 PN6 (4 “)
D2 (header connection size)
DN 100 PN6 (4 “)
DN 100 PN6 (4 “)
DN 100 PN6 (4 “)
D3 (gas connection size)
DN 80 (3”)
DN 80 (3”)
DN 80 (3”)
A (gas)
253
253
253
B (headers)
482
482
482
Table 4.3 Dimensions S-CBX cascade 540 to 930 kW.

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5. Explanation of Parts and Groups
Each cascade configuration exists of the following parts and groups:
1. The number of boilers as selected in chapter 3.
2. The frame group (with locking plates) as determined by the number of boilers.
3. An external pump for each boiler.
4. Connecting sets to connect the boilers to the hydraulic and gas header groups. Each connecting set
contains one gas, one supply and one return pipe. More details can be found in chapter 6.
5. Hydraulic and gas header group, existing of 1 gas, 1 supply and 1 return header, including all mounting and
connecting parts. More details can be found in chapter 7.
6. Low-loss header to connect the hydraulic group to the heating installation.
Figure 5.1 Cascade parts and groups.
Boilers (1)
Frame
group (2)
Hydraulic and gas
header group (5)
Low loss header (6)
Connecting sets (4)
Pump (3)

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6. Connecting Sets
Supply Connecting Set
Gas Connecting Set
Connection to boiler.
Connection to boiler.
Connection for pressure
relieve valve.
Ball valve.
Ball valve.
Coupling to supply header.
Coupling to gas header.
Return Connecting Set with External Pump
Connection to boiler.
Pump location.
Connection to pump.
Connection for boiler bleed valve.
Check valve.
Ball valve.
Coupling to return header.
Figure 6.1 Connecting sets
The gas connecting set should be connected to the gas connection on the boiler.
The supply connecting set must be connected to the boiler supply connection (front connection on the boiler)
and the return connecting set (longest) to the boiler return connection (back connection on the boiler).
The open connection in the supply connecting set is meant for a pressure relief valve, and the open connection
in the return connecting set is to be used for a boiler bleeding valve.

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7. Hydraulic and Gas Header Group
7.1 Headers
1. Gas header (yellow marking)
2. Supply header (red marking)
3. Return header (blue marking)
Figure 7.1 Parts hydraulic and gas header group
7.2 Support Beam and Support Brackets
Figure 7.2 Headers support beam and support brackets
1.
2.
3.
U-bolt
U-bolt
Support bracket
water headers
Support
bracket
gas header
Headers support beam
Seal plug

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7.3 Headers and Connecting Sets
Figure 7.3 Headers and connecting sets
Variant sizes
Depending on the cascade configuration the headers come in the following size varieties:
Header
Varieties
Gas header
DN50 / DN80
Water header (supply and return)
DN65 / DN80 / DN100
See also Table 4.1, Table 4.2 and Table 4.3.
1
2
red
blue
1. Gas connection set
2. Supply connection set
3. Return connection set
E67.5020.002
3
3
3

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8. Mounting the Frame
8.1 Frame elements
The first part of the actual installation of the cascade configuration is assembling the frame on which the boilers
will be hung.
The basic frame exists of the following elements:
•L-shaped stands
•Top beam
•In-between beam (middle beam)
•Mounting material (bolts, washers)
1
Locking strip
2
In-between beam
3
Top-beam
4
L-stand
5
Rectangular seal plug 70x50
6
Bolt M8x25 DIN933
7
Washer M8 DIN 125-1A
B
Figure 8.1 Frame elements

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The number of elements to be mounted depends on the number of boilers which have to be combined.
# Boilers
# L-
stands
# Top
beams
# In-between
beams
# Frame
braces
Width
beams
1*
2
1
1
1
440 mm
2
2
1
1
1
930 mm
3
2
1
1
1
1420 mm
4
3
2
2
2
930 mm
5
exists of a
2-boiler frame
and a
3-boiler frame
3
1
1
1
930 mm
1
1
1
1420 mm
6
option 1
3
2
2
2
1420 mm
option 2
4
3
3
3
930 mm
*A frame can also be mounted for a single boiler, although a 1 boiler configuration does not fall within the cascade scope of this manual.
Table 8.1 Frame elements per cascade set
Attention!
Each set of material for the required cascade configuration will contain the exact amount of material required for
the cascade configuration type ordered.
8.2 Procedure for Mounting the Frame
See also Figure 8.1.
To mount the frame, subsequently carry out the steps in the following procedure:
1. Check after unpacking that all parts are actually present.
2. Mount the in-between beam(s) between the L-stands.
Ensure that the beam’s flange hole falls over the raised edge of the L-stand connection hole.
Mount the beam(s) loosely; do not yet tighten the bolts.
3. Mount the top beam(s) between the L-stands.
Ensure that the beam’s flange hole falls over the raised edge of the L-stand connection hole
Mount the beam(s) loosely; do not yet tighten the bolts.
4. Level the L-stands, both vertically and horizontally.
Use a level and the adjustment bolts on the bottom of the L-stands.
Attention!
The frame must be levelled tension-free.
So do not tighten bolts or mount boilers before the frame has been levelled.
Attention!
After mounting the frame, the frame must be braced or mounted to the wall or ceiling to prevent the frame and
boilers from wobbling.
Check the local building regulations for the relevant requirements.

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9. Mounting the Gas Header
Attention!
All lines/piping must be mounted free of tension. The weight of all the components should be supported
separately from the boiler so there is no force on the connections.
Attention!
During mounting of the gas header group, it is very important that the position of the support beam as well as
the support brackets of the headers allow for some play (tolerance) for a neat installation. After finishing the
installation, the support beam and brackets can be tightened.
1. Mount the support beam(s) for the hydraulic and gas header group loosely between the legs of the L-stands.
2. Mount the support brackets for the gas header at nominal height. See also Figure 7.2.
3. Place the gas header(s) on the support brackets and fasten it (them) loosely with the U-bolts. Make sure
that the connections for the corresponding connecting sets are at the upper side of the header(s).
4. Next mount the boilers on the frame. See chapter 10.

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10. Mounting the Boilers on the Frame
1. Before mounting the boiler on the frame, ensure that the frame is level both horizontally and vertically. If
necessary, adjust with the adjusting bolts on the lower side of the frame (see Figure 10.1).
2. Hang the boilers on the frame.
3. Align the boilers with the L-stand in such a way that there is an exact 50 mm gap between the boilers.
4. Lock the suspension bracket with the locking strip to prevent the boiler from falling off the bracket (see
drawing).
5. Make sure that the boiler is at the right position (near level).
The boilers must hang backwards slightly (1º +/- 0.5º). If necessary, adjust with the adjusting bolts on the
lower rear side of the back panel (see Figure 10.1). When the adjusting bolts are not sufficient, the space
behind the bolts needs to be filled to achieve the correct position.
Attention!
The boiler must never lean forward in the mounted position.
6. Next mount the hydraulic group and connecting sets. See chapter 11.
Figure 10.1 Mounting details
Levelling frame
Locking
Levelling boiler

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11. Mounting the Hydraulic Group and the Connecting Sets
After the boiler has been mounted on the frame, the hydraulic group and the connecting sets must be mounted.
Attention!
All lines/piping must be mounted free of tension. The weight of all the components should be supported
separately from the boiler so there is no force on the connections.
Attention!
During mounting of the hydraulic and gas header group it is very important that the position of the support beam
as well as the support brackets of the headers allow for some play (tolerance) for a neat installation. After
finishing the installation, the support beam and brackets can be tightened.
1. Mount the support brackets for the return header at nominal height. See also Figure 7.2.
2. Place the return header(s) (bottom water header / blue) on the support brackets and fasten it (them) loosely
with the U-bolts. Make sure that the connections for the corresponding connecting sets are at the back of
the header.
3. Mount the connecting sets for the return header. See also Figure 7.3.
Attention!
An external pump (to be ordered separately) must be mounted between the return connecting set and the
boiler. Required for this are:
- pump supplied with 2 flat-seal two-part couplings;
- 1 flat-seal coupling for connection to boiler (inside thread / female thread)
- 1 flat-seal coupling for connection to connecting set (outside thread / male thread)
a. Fit the flat-seal couplings to the boiler and to the connecting set.
b. Mount the pump to the boiler; pay attention to its orientation.
c. Mount the connecting set to the pump; pay attention to its orientation.
d. Bend the flexible part of the return connecting set into a smooth bend.
e. Fit the connecting set to the return header (conical three-part coupling). Fit the loose part to the header
and then fasten the coupling.
4. Mount the support brackets for the supply header. See also Figure 7.2.
5. Place the supply header(s) (top water header / red) on the support brackets and fasten it (them) loosely with
the U-bolts.
6. Mount the connecting sets for the supply header. See also Figure 7.3.
The connecting set has a three-part coupling for the connection to the boiler.
a. Fit the loose part of the three-part coupling to the boiler.
b. Fit the connecting set to the coupling.
c. Fit the connecting set to the supply header (conical three-part coupling). Fit the loose part to the header
and then fasten the coupling.
7. Fit the gas connecting sets to the boiler and to the gas header.
8. When all parts are mounted correctly and are free of tension, fasten all couplings, bolts and U-bolts.
9. Next mount the low loss header. See chapter 12.

20
12. Mounting the Low Loss Headers
After mounting the hydraulic and gas header group and the connecting sets to the boilers, the low loss header
must be mounted to the supply and return headers.
Figure 12.1 Low loss header
Depending on the configuration of the cascade setup, one of the following low loss headers can be mounted:
Type
Size
Used for
Article number
Size
DN 65
2,5”
Cascade installation up to 360 kW
E68.0300.501
120 x 120 x 3
DN 80
3”
Cascade installation 360 up to 540 kW
E68.0300.502
140 x 140 x 4
DN 100
4”
Cascade installation 540 to 930 kW
E68.0300.503
200 x 200 x 5
Table 12.1 Low loss header connection sizes
The low-loss header can be fitted on the right-hand side as well as on the left-hand side without making any
alterations to the supplied parts. The gas connection can also be fitted on one of both sides, independent from
the side chosen for the low loss header.
1. Mount the low loss header.
It can be mounted on the right-hand or the left-hand side of the supply and return headers, whatever the
best place for connecting the headers to the heating installation.
2. Fit the supplied flanges on the opposite end of the supply and return headers in order to block those ends.
3. Fit the supplied seal cap on the opposite end of the gas header in order to block that end.