System Details - Baxi Solo 3 PFL 30 Installation & Servicing Instructions Manual

Boiler
Fully Pumped System
Fig. 2
Examples of systems which require a bypass
are:-
a) A system controlled by non-electrical valves
e.g. mechanical thermostatic control valves both
on the radiators and the hot water circuit.
b) A system using twin zone valves (e.g.
Honeywell 'S' Plan) (Fig. 3).
c) A system using a 3 port divertor valve (Fig. 4)
does not normally require a bypass therefore this
system is recommended. The exception to this is
where thermostatic radiator valves are used and
then a bypass is required.
NOTE: For 'S' Plan systems the bypass flow
circuit must be situated between pump and
zone valves as option A shows (Fig. 2).
The bypass circuit can be:-
a) For all boilers a minimum of 6 metres of
22mm copper pipe, (measured between the
boiler flow and return connections). It should be
fitted with a lock shield valve opened at least 1
full turn or a proprietary bypass valve set to give
a minimum flow rate of 8 litres/min (1.8 gal/min)
(Option C, Fig. 1 & Option A, Fig.2).
b) A radiator fitted with lock shield valves. The
radiator output should be a minimum of 800
watts (2,700 Btu/h). Typically a convector type
radiator with an area of 3750 cm 2
adequate (Option B, Fig. 1).
c) Any circuit that provides the same operating
conditions as option A or option B (Figs. 1 & 2).
© Baxi Heating UK Ltd 2009
Option B
Option C
Radiator Circuit
Fig. 1
Air Vent
Pump
Option A
Air
Vent
Twin Zone
Valve System
Fig. 3
Air
Vent
(4 sq ft) is
3 Port Divertor
Valve System
Fig. 4

3.0 System Details

3.1
1. The appliance is suitable for use with open vent fully
pumped systems and sealed systems where additional
control protection is required.
The following conditions should be observed on all
systems:
• The static head must not exceed 30m (100ft) of water.
• The boiler must not be used with a direct cylinder.
• The boiler is fitted with a timed pump overrun that will
operate for approximately 8 minutes.
• Drain cocks should be fitted to all system low points.
• All gas and water pipes and electrical wiring must be
installed in a way which would not restrict the servicing of
the boiler.
• Position isolating valves as close to circulating pump as
possible.
Treatment of Water Circulating Systems
All recirculatory water systems will be subject to
corrosion unless they are flushed and an appropriate
water treatment is applied. To prevent this, follow the
guidelines given in BS 7593 "Treatment of Water in
Radiator
Domestic Hot Water Central Heating Systems" and the
Circuit
treatment manufacturers instructions.
Treatment must involve the use of a proprietary
cleanser, such as Sentinel X300 or X400, or Fernox F3
and an inhibitor such as Sentinel X100 or Fernox MB-1.
Full instructions are supplied with the products, for
further information contact Sentinel (0800 389 4670) or
Fernox (0870 870 0362).
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 inhibitor manufacturer's
Radiator
instructions. (Test kits are available from inhibitor
Circuit
stockists.)
For information or advice regarding any of the above
contact Technical Enquiries 0844 871 1555.
Typical Systems
Arrangement
3.2
1. The boiler is fitted with a pump overrun device which
allows the removal of residual heat from the boiler.
NOTE: The pump overrun will operate for
approximately 8 minutes. The system design must
therefore, always provide an open circuit for water to
circulate between the boiler flow and return.
2. See information opposite "Examples of systems which
require a bypass are".
Radiator
Circuit
Water Circulating Systems
Bypass Requirements
7