User manual

Page 5
INTRODUCTION
Warning: For trouble free operation of the boiler, and to be assured of the full guarantee, the following items are required
together with other stipulations in this manual:
A. An automatic air and dirt separator (alternative pages 23&24)must be installed in the system and a strainer installed
in the return pipework. Installation of ancillaries and devices must be installed as shown on pages 19 or 20.
B. Minimum static water pressure must be more than 1 bar. Maximum 4 bar and 6 bar on request at same cost.
C. The system is flushed, free of water leaks, water tested, and additive utilised where necessary. (see page 17 and
page 23/24 for information relating to old systems).
D. The Boiler must be level. The Boiler must be vented, the auto air vent cap (where fitted) must be open or manual air
vent (where fitted) utilised. Open all system auto air vents .
E. Low and high water cut out pressure switches ( usually in the fill unit) connected in the Boiler volt free control circuit
in series with other controls on terminals 13 & 14 (PAGE 25) or by 0 volt when using external 0 to 10 volt control by
others. See pages 25,26&27
F. Control of Boiler on/off must never be by interruption of the mains supply.
G. When using a common flue, the flue system must be in negative pressure if not contact Strebel.
These instructions are written for the installer of Strebel products and together with the Electrical Control And
Commissioning Manual contain all necessary information on the installation and adjustment of S-CB boilers. Please read all
these instructions fully before installation to ensure that all work is done safely and correctly. We suggest that you keep
these instructions near the boiler.
Operation of the Strebel S-CB Boiler
The heating boilers from the Strebel S-CB series are heating boilers with maximum high efficiency. Such performance is
reached by, among other things, using a special heat exchanger made of stainless steel. The heat exchanger allows flue
gases to cool down below condensation point, condensing the flue gases and releasing extra heat. This has a positive
impact on the efficiency, exceeding 100%net calorific.
 S-CB flue gases have a low temperature (below 85°C), the boiler needs to have a high efficiency approved stainless
steel or plastic flue system .Aluminium flue systems are not allowed to be connected to these boilers. Adequate drain
points must be added to the flue system with a “u” trap.
Controls
The Strebel S-CB Boiler adjusts to the demand for heat by using flame modulation and external controls. That is on the
basis of 1) 0 to 10 volt control. 2) Strebel optimiser control. 3) Built in weather compensation with an outside detector.
4) RC or E-BUS .For RC or E-Bus system, see separate booklet.
The boiler control is equipped with:
Control for a DHW Cylinder with a diverter valve or a pump (pump via a relay both not supplied) Connection for a Heating
pump via a relay (pump and relay not supplied) Connection for a room thermostat, on/off control, optimiser or 0 to 10 volt
control.
Frost protection
Frost protection does not protect the system or system pumps. It protects the boiler.
Frost protect the system by fitting devices to link out any timer controls. In a frost condition (at 7° Boiler temperature) the
Boiler internal pump starts. When the boiler water temperature falls down to 3°C, the burner is also ignited. This operation
will cease as soon as the boiler temperature has reached 10°C.
Cascade control
Using the integrated cascade control, a maximum of 12 boilers can be controlled in a cascade configuration. The Cascade
has in-built full logic step control. The Boiler will require a Flow temperature sensor and 2 wires to each boiler in a daisy
chain. When using a common flue that is not in negative pressure the cascade control must be used
0-10 VDC connection
The boiler is equipped to take a 0-10 VDC signal from a controller by others (set at time of commissioning) Controlling up
to 12 boilers (temperature) in cascade, utilising the built in cascade manager. (0 Volt is no heat demand.) The Boiler will
require a Flow temperature sensor at extra cost and 2 wire link to all boilers in the cascade.