11
IMAX XTRA EL
-
Installation & Servicing
GENERAL
Detail reference should be made to the appropriate
standards listed on page 4.
The information and guidance given below is not intended
to override any requirements of the above publications
or the requirements of the local authority, gas or water
undertakings.
The vertical distance between the pump and feed/expansion
cistern MUST comply with the pump manufacturer's
minimum requirements, to avoid cavitation. Should these
conditions not apply either lower the pump position or raise
the cistern above the minimum requirement specified by
Ideal Boilers
. The isolation valves should be fitted as close
to the pump as possible.
The information provided is based on the following
assumptions:
1.
An independent open vent/safety pipe connection is
made immediately after the system flow pipe connection.
2.
An independent cold feed/expansion pipe connection
is made immediately after the open vent/safety pipe
connection.
3.
The maximum flow rate through the boiler is based on a
temperature difference of 20
o
C at full boiler output.
4.
The boiler is at the highest point of circulation in the
system. Systems designed to rise above the boiler flow
tappings will automatically require a minimum static
head higher than that shown.
5.
The position of the open vent/safety pipe above the
expansion cistern water level is given as a guide
only. The final position will depend upon the particular
characteristics of the system. Pumping over of water
into the expansion cistern must be avoided.
6.
Both open vent/safety pipe and cold feed/expansion
pipes must be of adequate diameter to suit the output of
the boiler. Refer to Tables below and BS 6644:2005.
5 OPEN VENTED SYSTEM REQUIREMENTS
Note.
This diagram does not show safety valves, water
flow switches, etc. necessary for the safe operation
of the system.
Open Vent Pipe Sizes
Cold Feed Pipe Sizes
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IMPORTANT
:
If an open vented system is required please
ensure a maximum flow temperature of 80ºC is not exceeded.
Open vent pipe size is determined using:
A = 3.5 x Q
R
When:
- Q
R
is heat input in kW
- A is area in mm
2
A minimum pipe size for the cold feed should be
50mm (bore) or 2" (DN).
Note; Steel pipe sizes complying with medium or
heavy quilting or BS 1387.
