Quick Start Manual
6.0 System Details
13
© Baxi Heating UK Limited 2005
6.1 Central Heating Circuit
1. The appliance is suitable for fully pumped SEALED SYSTEMS
ONLY.
This boiler is fitted with a flow switch interlock that prevents
it from firing when the heating demand is satisfied.
The boiler is designed so that it will heat the house to the
desired room temperature as quickly as possible by running
at the maximum radiator temperature of 82°C. Once this
room temperature is achieved the boiler will then reduce the
radiator temperature to as low a level as possible, while still
achieving the desired room temperature, thereby giving the
most efficient use of gas and the most comfortable room
temperature possible.
The boiler will be able to achieve this performance if a room
thermostat is fitted or with a fully TRV’d system without a
bypass.
This boiler does not require a bypass. To comply with Part
L1 of the Building Regulations the heating system into which
the boiler is installed should include the following:
a) zone controls
b) timing controls
c) boiler control interlocks
Such a system needs to be fully pumped and must provide
independent temperature and time control to both the
heating and hot water circuits and have a boiler interlock.
The boiler should be controlled so that it operates on
demand only. Where it is proposed to effect control by
thermostatic radiator valves, a room thermostat (or other
device such as a flow switch - a flow switch is integral to this
boiler) should also be provided to switch off the boiler when
there is no demand for heating or hot water.
The interlock for CH circuit can be provided in either of the
following ways:
a) A Room Thermostat with at least the radiator
nearest the room stat not TRV’d.
b) A fully TRV’d system without a bypass.
A fully TRV’d system with a bypass that has not been valved
off does not comply with Part L1 of the Building Regulations.
If the system is fully TRV’d with a bypass then this feature will
not be available, in this case the radiator temperature can be
reduced to provide more efficient operation. (see User
instructions).
• The condensate drain and pipes must be free from leaks.
Information
In GB it is necessary to comply with the Water Supply (Water Fittings)
Regulations 1999 (or for Scotland, The Water Byelaws 2000, Scotland). The Baxi
Combi 133, 100, 80 HE Plus Combination Boilers are an Approved Product under
the Water Regulations.
To comply with the Water Regulations your attention is drawn to The Water
Regulations Advisory Service (WRAS) which gives full details of the requirements.
In IE the requirements given in the current edition of I.S. 813 “Domestic Gas
Installations” and the current Building Regulations must be followed.
Treatment of Water Circulating Systems
• All recirculatory water systems will be subject to corrosion unless an
appropriate water treatment is applied. This means that the efficiency of the
system will deteriorate as corrosion sludge accumulates within the system,
risking damage to pump and valves, boiler noise and circulation problems.
• When fitting new systems flux will be evident within the system, which can
lead to damage of system components.
• All systems must be thoroughly drained and flushed out. Using for example
Betz-Dearborn Sentinel X300 or X400 or Fernox Superfloc Universal
Cleanser. They should be used following the flushing agent manufacturer’s
instructions.
• System additives - corrosion inhibitors and flushing agents/descalers should
comply to BS7593 requirements, e.g. Betz-Dearborn Sentinel X100 and
Fernox-Copal which should be used following the inhibitor manufacturer’s
instructions.
Failure to flush and add inhibitor to the system will invalidate the
appliance warranty.
• It is important to check the inhibitor concentration after installation, system
modification and at every service in accordance with the manufacturer’s
instructions. (Test kits are available from inhibitor stockists.)
• For information or advice regarding any of the above contact Technical
Enquiries.