Strebel S-CB+ Series, Installation Operating & Maintenance Manual

Page: 27 / 125

S-CB
+
Boiler Range Manual
27
7.2 Pumps: maximum electrical power
General
- The start current of a conventional pump is approximately 2½ x its nominal current.
- The maximum switch current of the PCB is 5 A.
When the two statements are combined, the conclusion is that nominal currents of pumps, controlled by the PCB,
may not exceed 2 A.
Pump P1 - boiler pump.
This modulating pump is part of the appliance. The speed and power consumption depends on the Delta T across
the heat exchanger and is controlled by the burner controller.
Pump P2 - calorifier pump.
Pump P2 is a DHWi pump and is used when P4AA = 1, meaning the appliance is an indirect calorifier.
Pumps P1 and P2 are connected to one fuse of 5 A, so their total nominal current may not exceed 5 A. To limit the
inrush current, the switching sequence has been modified so pump P2 always switches 100 ms later than pump
P1.
The maximum nominal current of pump P2 must also be 2 A, again due to the inrush current.
3 way valve.
The combined nominal current of pump P1 and the 3 way valve must be smaller than 5 A.
So, the inrush current of the 3 way valve must be lower than 3 A.
Pump P3 - system pump.
The nominal current of pump P3 must be equal to or lower than 2 A.
Warning (EC pumps):
In case of using an electronic commutating pump, the relays 1, 2 or 3 may not be used for the power connection,
because of the inrush current of the electronics of the pump.
Directly connect the pump to an external power supply.
Control connections of an EC pump can be established in several ways, set by parameter P5BN.
See § 11.1.7 on page 79.
8 FLUE GAS AND AIR SUPPLY SYSTEM
8.1 General
The boiler has a positive pressure flue system. The available combined pressure drop for the inlet and outlet sys-
tem
is 200 Pa for the complete boiler range.
Notice:

Install the horizontal flue components with an angle of 3° downwards in the direction of the boiler (roughly
equal to five centimetres for every linear meter). When not installed accordingly, it may result in condensate
building-up in the flue gas tube, eventually causing component failure.

Wall flue terminals are generally used up to 60-80 kW. Using these terminals with larger capacities will give
unpleasant large condensate clouds.

When using a wall terminal, there is the possible risk of ice building-up on surrounding parts/structures, be-
cause the condensate will freeze. This risk should be taken into account during the design phase of the heat-
ing installation.
Note
Because the flue gases can have a low temperature, the boiler needs to have a high efficiency approved stainless
steel or plastic flue system. These materials, including the gaskets, should be usable for positive pressure flue gas
systems and have a temperature class of
T120 .