Flue System - Keston C90 Installation And Servicing Instrucnion

WD352/0/2003
2.7.5 Air Elimination
In the initial charge of water to the boiler system and in all subsequent additions
of water to the system some air will be dissolved in the water. As the water is
heated the air is driven out of the solution and will collect in high spots in the
system. These air bubbles can interfere with pumping and heat transfer and
must be eliminated.
Installation of air bleed valves at the high spot(s) in the system will allow for air
elimination when filling the system and will allow re-venting in a day or so after all
air has been driven out of solution.
2.7.6 System Pump Selection
The C90 and C110 feature integral
circulating
sufficient excess head to drive
through
However, a system pump will be
required to provide circulation of
water from the balance header,
around the system. This system
pump should be selected to provide
the required system flow rate at the
pressure drop created by the index
circuit.
2.8

FLUE SYSTEM

NB:
used. Do not re-use the existing boiler flue installation.
2.8.1 Design
Individual air supply and flue outlet pipes are
used. The material used for flue outlet &/or air
inlet must be Keston Composite Pipe of an
internal diameter of not less than 100mm.
Suitable pipe and fittings can be obtained from
Keston Boilers Ltd via its appointed distributors.
Both flue outlet terminal and air inlet terminal are
supplied and are illustrated in Figure 2.8.1. Both
terminals are identical.
.
Although both terminals are identical great care
must be taken to ensure that the air intake is
positioned in such a way as to ensure rain cannot
enter the air intake pipework. Boiler damage due
to water entry through the air intake pipework is
not covered under the appliance warranty.
Installation & Servicing Instructions
Chapter 2 - Boiler Location
pumps which
the balance header.
When installing a replacement boiler a new flue system must be
8.0
have
7.0
6.0
5.0
4.0
3.0
2.0
1.0
20
Fig 2.7.6 Available Pump Head Graph
Flue Outlet/Air Inlet Terminals
The Keston C90 & C110
40 60 80
Water Flow - L/min
Figure 2.8.1 : Terminals
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