13
Super Plus -
Installation and Servicing
Safety Valve:
A safety valve must be sized and fitted in accordance with BS.6644.
The valve should be set at 0.7 bar (1 0 lb/in
2
) above the available
static head of water over the boiler.
The maximum safety valve setting is 0.7 bar (10 lb/in
2
) above the
maximum design operating head of 6.0 bar (85 lb/in
2
, i.e. 6.7 bar
(95 lb/in
2
)
Pressure Gauge
The water pressure gauge and temperature gauge must comply
with BS.6644.
Water flow switch
A water flow switch must be fitted to protect the boiler from pump
failure.
Vent, Cold Feed
The open vent and cold feed pipe sizes must comply with BS.6644
and must be of the following minimum size:
The drain valve must comply with BS.2879 and be operated with
a removable key.
GENERAL GUIDANCE ON APPLICATIONS
See Fig.13
Fig.13 is intended to provide basic information only on the
application of the
Super Plus
Boilers.
It is essential that the water flow rates given above be maintained
within the limits stated. Therefore, any compensating devices
must not be connected to the boilers directly, but may be used in
conjunction with a mixing header. The mixing header must be sized
at least one size larger than the boiler flow and return manifold
size; to avoid hydraulic interference between the boiler primary
pump and system zone pumps.
The use of a mixing header means that compensating controls can
be used to operate mixing valves on a variable temperature circuit,
without affecting the water flow rate through the boiler.
Fig. 14 shows how constant and variable temperature circuit can
be used on low and high head applications.
The following points should be noted:
1.
The recommended positions of the cold feed and open vent
are shown, sizes should comply with BS.6644:1986. If isolating
valves are to be fitted in the flow and return pipes of the boiler
they must not isolate the boiler from the open vent, safety valve
or cold feed.
2.
The minimum tank height shown is measured from the highest
point of the system and must be increased, if necessary, to
comply with pump manufacturers' requirements.
3.
The open vent height above tank water level cannot be
guaranteed adequate in all circumstances and does not take
into account any instantaneous changes in head brought about
by ancillary equipment operating.
4.
Water flow switch is shown in its recommended position. It
MUST NOT be located on the mixing header where operation
of zone pumps can cause reduction in flow.
5.
Production of condensate: When operating normally and
the design return temperature has reached 70
0
C the boiler
produces virtually no condensate. At lower temperatures the
amount of condensate increases. It is normal for condensate
to be produced as the boiler heats up from cold and, provided
the time taken for the return to reach 71
0
C is not excessive,
no harm will result.
If, however, large quantities of condensate are produced for
long periods, this can adversely affect burner performance
and cause the control box to lock out.
If the water contents of a system is very large, it is advisable to
switch on individual zones from cold, in sequence with a time delay
sufficient to allow the boiler return temperature to reach 55
0
C as
quickly as possible.
The condensate drain should be run in accordance with British
Gas Publication IM22.
ELECTRICAL SUPPLY
230 Volt 50 Hz Single Phase A.C.
Consumption:
450 Watts maximum per module (excluding remote alarms, etc.)
Note:
External wiring and any installer supplied remote warning lights
MUST be in accordance with the I.E.E. (BS7671) Regulations and
any local regulations which apply.
The method of connection to the mains supply should facilitate
complete electrical isolation of the boiler.
Connection should be made via a fused double pole switch, or fused
spur box, serving the boiler only and incorporating contacts with
a separation of at least 3 mm in all poles. The point of connection
should be readily accessible and adjacent to the boiler.
The water flow switch and any other overriding safety devices
should be wired in series with the isolation mains supply to the
boiler. Remote indication connections of 'Burner On', 'Lockout' and
'Overheat are provided in the sequence control wiring centres. The
loads should not exceed 1 amp resistive
GENERAL
GENERAL
