5
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Installation & Servicing
GENERAL
Note.
•
With the boiler firing at maximum rate, the temperature
differential should not be less than 10degC.
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Higher flow rates required for lower temperature
differentials could lead to erosion of the heat exchanger
water ways.
•
With the boiler operating at minimum waterflow rate, the
temperature differential should not be greater than 20degC.
Lower flow rates generating higher temperature differentials
will lead to lockout of the boiler.
•
The lower the return temperature to the boiler, the higher the
efficiency. At return temperatures of 55ºC and below, the
difference becomes more marked because the water in the
flue gases starts to condense, releasing its latent heat.
The air vent inside the boiler is not for ventilation of the whole
system. An additional air vent should be fitted to the highest point
of the system.
Drain taps MUST be located in accessible positions, which
permit the draining of the whole system – including the boiler and
hot water storage vessel. The boiler is equipped with its own
drain tap, but this must not be used for draining of the whole
system as this could lead to system dirt gathering in the heat
exchanger, causing damage.
In installations were all radiators have been provided with a
thermostatic valve (TRV), or all heating zones have individual
zone isolation valves, then a bypass will be required to ensure
water circulation through the boiler during pump overrun. A mixing
header (see separate section) will perform this task. Alternatively
this can be best achieved by means of a pressure differential
valve, which is installed in a bypass between the flow and return
pipes. If a bypass is used it should be fitted at least 6m from the
boiler, and be capable of allowing a minimum flow rate to achieve
a temperature differential of no greater than 20degC at minimum
gas input.
WATER TREATMENT
The
boiler has an ALUMINIUM alloy heat exchanger.
Corrosion will always occur within a heating/hot water system to
a greater or lesser degree irrespective of water characteristics,
unless the initial fill water from the mains is treated. For these
reasons Caradon Ideal Limited strongly recommends that the
system be thoroughly cleaned prior to the use of a stable inhibitor
which does not require continual topping up to combat the effects
of hardness, salts, and corrosion on the heat exchanger and its
associated systems.
Therefore it is important that if water treatment is used it is
suitable for the material of the heat exchanger. The ONLY water
treatments approved are Fernox Copal or MB1, GE Betz Sentinel
X100 or Salamander Corrosion Guard inhibitors and associated
water treatments, which must be used in accordance with
manufactures instructions. Current suitability should be
confirmed directly with the manufacturer.
G E Betz Ltd, Sentinal Division, Foundry Lane, Widnes, Cheshire
WA8 8UD, Tel: 0151 424 5351
or
Fernox Manufacturing Co. Ltd., Cookson Electronics, Forsyth
Road, Sheerwater, Woking, Surrey, GU21 5RZ Tel: 01799 521133
or
Salamander Engineering Ltd., Unit 24, Reddicap Trading Estate,
Sutton Coldfield, West Midlands, B75 7BU. Tel: 0121 3780952
Artifically softened water must NOT be used to fill the system.
CONDENSATE DRAIN
A condensate drain is provided on the boiler. This drain must be
connected to a drainage point on site incorporating a water trap
as detailed in Frame 11. All pipework and fittings in the
condensate drainage system MUST be made of plastic - no
other materials may be used. See Frame 11 for connection
details.
IMPORTANT. Any external runs must be kept to a minimum and
insulated. This is to avoid freezing in cold weather causing
blocking.
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.
Ideally the boiler should be placed on a plinth exceeding the
plan area of the boiler by 75mm on each side and at least
100mm high, in order to assemble the condensate trap (refer to
Frame 11). An alternative to this base would be a 100mm deep
well next to the boiler (refer to Frame 6).
The boiler must not be fitted outside.
ELECTRICAL SUPPLY
WARNING This appliance must be earthed.
A 230V - 50Hz mains supply is required, fused at 3 amps.
Wiring external to the appliance MUST be in accordance with the
current I.E.E. (BS7671) Wiring Regulations and any local
regulations which apply.
The point of connection to the mains should be readily
accessible and adjacent to the boiler.
WATER CIRCULATION SYSTEM
Due to the compact nature of the boiler, the heat stored within
the castings at the point of shutdown of the burner must be
dissipated into the water circuit to avoid overheating. In order to
control pump operation after burner shutdown the boiler control
box incorporates a 5 minute pump overrun facility. A system
pump must therefore be connected to the terminals provided in
the boiler. This connection must be done via a relay.
When sizing pumps, reference should be made to the
appropriate graphs 1 or 2 which show the boiler resistance
against flow rates to achieve the required temperature
differential.
Flow rates for common systems using either 11 degC or 20
degC temperature differentials are given in the table below and
highlighted on graphs 1 and 2. These figures are based on an
appliance running in condensing mode. Slightly lower flow rates
would be required for an appliance run in non-condensing
mode.
Table 3
11 deg C
20 deg C
F80
1.79 l/s
0.98 l/s
F120
2.68 l/s
1.47 l/s
F160
3.58 l/s
1.97 l/s
F200
4.47 l/s
2.46 l/s
F240
5.37 l/s
2.95 l/s
F280
6.26 l/s
3.44 l/s