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In practice the deposition of these salts is liable to cause
noises from the boiler body or even premature boiler failure.
Corrosion and the formation of black iron oxide sludge will
ultimately result in premature radiator failure.
Open vented systems are not completely sealed from the
atmosphere if proper venting and expansion of system water
is to be achieved. The same tank is used to fill the system with
water and it is through the cold feed pipe that system water
expands into the tank when the boiler passes heat into the
system. Conversely, when the system cools, water previously
expelled is drawn back from the tank into the system together
with a quantity of dissolved oxygen.
Even if leakage from the heating and hot water system is
eliminated there will be evaporation losses from the surface of
the tank which, depending upon ambient temperature, may be
high enough to evaporate a large portion of the system water
capacity over a full heating season.
There will always be corrosion within a heating or hot water system
to a greater or lesser degree, irrespective of water characteristics,
unless the initial fill water from the mains is treated. Even the
water in closed systems will promote corrosion unless treated.
For the reason stated, Caradon Plumbing Limited strongly
recommend that, when necessary, the system is thoroughly
cleaned, prior to the use of stable inhibitor, which does not require
continual topping up to combat the effects of hardness salts and
corrosion on the heat exchangers of the boiler and associated
systems.
Caradon Plumbing Limited advise contact directly with specialists
on water treatment such as:
Fernox Manufacturing Co. Ltd.,
Tandem House,
Marlowe Way,
Croydon.
Surrey CRO 4XS
Tel 0870 5601 5000
INSTALLATION REQUIREMENTS
The appliance must be installed by a CORGI ( ) registered
installer.
The installation of the boiler must be in accordance with the
4
SEALED (PRESSURISED) SYSTEMS
Working pressure 6 bar maximum.
Particular reference should be made to BS. 6644: Section 2;
Subsection 11 and Guidance note PM5 "Automatically
controlled steam and hot water boilers" published by the
Health and Safety Executive.
The information and guidance given below is not intended to
override any requirements of either of the above publications
or the requirements of the local authority, gas or water
undertakings.
In general commercial closed pressurised systems are
provided with either manual or automatic water make up.
On both instances it will be necessary to fit automatic controls
intended to protect the boiler, circulating system and ancillary
equipment by shutting down the boiler plant if a potentially
hazardous situation should arise.
Examples of such situations are low water level and
operating pressure or excessive pressure within the system.
Depending on circumstances, controls will need to be either
manual or automatic reset. In the event of shutdown both
visual and audible alarms may be necessary.
8
GENERAL
or
Sentinel Division
Betz Dearborn Ltd.,
Widnes,
Cheshire, WA8 8UD
Tel. 0151 424 5351.
relevant requirements of the Gas Safety Regulations, current I.E.E.
(BS.7671) Regulations, Model Water Bye-laws, local water
authority bye-laws and it should also comply with any relevant
requirements of the local gas region, local authority and the
relevant British Standard Codes of practice and building
regulations.
FOR SMALL PIPE INSTALLATIONS:
BS. 6891;
Installation of low pressure pipework
FOR LARGE PIPE INSTALLATIONS:
British Gas Publications:
IM11:
Flues for Commercial and Industrial Gas
Fired Boilers and Air Heaters.
Gas Installations
IGE-UP-1:
Purging Procedures of Non-domestic Gas
Installations. Soundness Testing Procedures
for Industrial and Commercial.
IGE-UP-2:
Guidance notes on the Installation of Gas
Pipework, Boosters and Compressors in
Customer's Premises Equal to or Greater
than 25mm (Non-domestic).
BS.6644:
Installation of Gas Fired Hot Water Boilers
60kW to 2MW.
BS 6880 Pt 1-3: Water Supply.
CP342:2:
Centralised Hot Water Supply.
Model Water Bye-laws
Manufacturers notes must not be taken, in any way, as
overriding statutory obligations.
FOUNDATION
The boiler must stand on a non-combustible floor (i.e. concrete
or brick) which must be flat, level and of a suitable load bearing
capacity to support the weight of the boiler (when filled with
water) and any ancillary equipment.
If the boiler is mounted on a plinth then the dimensions must
exceed the plan area of the boiler by at least 75mm on each
side.
Pressure vessels used must comply with BS. 4814 and
must be sized on the basis of the total system volume and
initial charge pressure.
Initial minimum charge pressure should not be less than 0.5
bar (7.2 psi) and must take account of static head and
specification of the pressurising equipment. The maximum
water temperatures permissible at the point of minimum
pressure in the system are specified in Guidance Note PM5.
When make-up water is not provided automatically it will be
necessary to fit controls which shut down the plant in the
event of the maximum system pressure approaching to
within 0.35 bar (5 psi) of safety valve setting.
Other British Standards applicable to commercial sealed
systems are:-
BS. 6880: Part 2.
BS. 1212
BS. 6281: Part 1
BS. 6282: Part 1
BS. 6283: Part 4
Concord CXA
- Installation and Servicing
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