Keston 50 - GC Installation And Servicing Instructions page 14

WD50/2/1997 Chapter 2 - Boiler Connections
Boiler
Keston
Safety
Relief
Valve
Drain
Cock
2.7.3
2.7.4
Installation & Servicing Instructions
Strainer
Pressure
Gauge By-pass
Bal.
Valve
Pump
Expansion
Vessel
Figure 2.7.2 : Sealed System Diagram
Hot Water System (if applicable)
The hot water storage vessel must be of the indirect type (certain direct cylinders
can be used provided they are suitably adapted by fitting an immersion
calorifier). DIRECT CYLINDERS MUST NOT BE USED. Further guidance is
provided in BS 1394. It is advisable to fit a lockshield valve on the cylinder return
to enable balancing of flow rate through the cylinder.
Boiler By-pass Piping
Boiler water flows are critical to the operation of the boiler. If flow cannot be
maintained through the system piping to meet the minimums required by the
boiler (see paragraph 2.7 (g)). Insufficient water flows through the boiler will cause
the boiler to "kettle" or even produce steam which can damage the heat
exchanger and will invalidate the heat exchanger warranty.
It is normally advisable to incorporate a boiler by-pass in the system, especially if
thermostatic radiator valves are used. The by-pass should be fitted with a
lockshield valve to permit balancing of the by-pass flow rate. The flow/return
differential should be 10
maintain this condition with the radiators fully heated.
Page : 11
The Keston 50, 60 & 80 Condensing Boilers
Air Vent
L/S
RETURN
HEATING CIRCUIT
FLOW
Double Check
BS 1010:2
Valve
Stop Tap
Test Cock
o o
C to 15 C. The lockshield valve can be adjusted to
Make -up vessel.
Max. capacity of
3 lt. (5pt)
Hose
Non-Return
Union
Valve
bib tap
Auto Air
Vent
Hosepipe
(disconnected
after filling)
Hose
Connector