3.
3.1
3.2
3.3
3.4
3.5
3.6
SYSTEM GUIDANCE
(Chaffoteaux Ltd. recommendations).
General
The CHALLENGER is a low water content boiler designed
ONLY for use with fully pumped systems. It may be used
with open or sealed systems, all safety controls exclu-
ding the pressure relief valve being incorporated in the
boiler. The thermostat is adjustable and, on its maximum
setting, gives a nominal 82 “C (180 “F)i4 “C (7 “F).
Detailed recommendations for the water circulation are
given in BS 5376.2 1976, BS 5449.1 1977 and BS
5546:1979.
Thermostatic control should be fitted to the cylinder and
heating circuits.
Strainers
Where the CHALLENGER is used as a replacement for a
boiler on an existing system, ideally the system should
be flushed and cleaned using a suitable chemical cleaner
following the manufacturer’s recommendations and fitted with a strainer similar to that manufactured by Ho-
neywell.
Control Schemes
The boiler is electrically controlled. See section 3.11.
Most normal pumped primary control schemes can be
used including thermostatic radiator
and
cylinder valves.
When using motorised valves the controls should be so
arranged to switch off the boiler when circuits are satisfied.
Chaffoteaux can be consulted where technical assistance is required.
Circulation Pump
The system circulating pump should be sized relative to
the resistance of the connected load and the system design selected. The water flow rate through the boiler
should not be less than shown in section 1.4. The pump
must be installed between isolating valves. Most pump
manufacturers require a minimum static head on the
pump inlet to prevent cavitation. For boiler resistance
see graph on page 3.
Cold feeds and open vents
The cold feed and open vent should be so positioned
that pumping over and sub-atmospheric pressures are
avoided see recommendations for various layouts on
page 7.
Automatic Air Separator
Chaffoteaux Limited strongly recommend the inclusion
of a British Gas accepted automatic air separator in the
system as shown in fig. 9.
The open vent pipe should rise continuously from the
system pipework.
It should not be entered horizontally into the system pi-
pework. The use of an enlarged T to create a low velocity
point is recommended. The preferred arrangement is
shown in fig. 9.
3.7 Cylinder
The domestic hot water cylinder used with the CHALLENGER must be of the indirect and high recovery type
to BS 1566 Pt. 1. Single feed cylinders are not suitable
for use with the appliance. Flow and return pipework to
the cylinder should be in 22 mm pipe.
3.8 Feed and Expansion Tank
The feed and expansion tank should be adequately sized
to accept the system water expansion, it should not be
mounted closer than 9 in. to a ceiling to allow access to
the ball valve.
3.9
Inhibitors
Chaffoteaux Limited do not generally recommend the
inclusion of an inhibitor with heating and hot water systems, utilising CHAFFOTEAUX boilers. It is, however, appreciated that the use of a corrosion and limescale inhibitor may be desireable or specified.
The following are the appliance manufacturer recommendations :
Use only a British Gas or similar approved inhibitor
from the Fernox range manufactured by Industrial
(Anti-Corrosion) Services, Brittanica Works, Arkesdon
Road, Clabering, Nr Saffron Waldron.
Use only the quantities specified by the inhibitor
manufacturer.
Cleanse the system as may be required be the inhibi-
tor manufacturer.
Add inhibitor only after flushing when finally refilling
the system.
3.10 Add on devices
This appliance is approved by British Gas for safety and
performance. It is important that no external control devices - eg. flue dampers, economisers etc. - be directly
connected to this appliance unless covered by these lnstallation Instructions or agreed by the Manufacturer in
writing.
Any direct connection of a control device not approved
by the manufacturer could invalidate British Gas approval and also infringe the Gas Safety Regulations.
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