Baxi 100/2 HE Plus Installation & Servicing Instructions Manual page 11

Copper
0.5m
Boiler
Fig. 9
1000mm
Min
150mm
Boiler
Return
Typical Low Head Installation
Fig. 10
Automatic Air
Vent
1000mm
Min
Boiler
If Conditions Require,
Fig. 11
This System Possible
200mm
Min
Boiler
Alternative Low Head Installation
Fig. 12
Copper
0.5m
Flow
Return
Copper
1m
22mm
Open Vent
45°
15mm
400mm
Cold
Min Head
Feed
Max
Pump
Flow
22mm
Open Vent
45°
15mm
400mm
Cold
Min Head
Feed
150mm
Max
Pump
Return
22mm
Feed & Vent
Pipe
Air
Separator
Pump
Flow
Return
6.0 System Details
6.3 Pipework
1. The sizes of flow and return pipes from the boiler
should be determined by normal methods, according to
the requirements of the system. The connection to the
boiler is 28mm (compression).
2. Due to space requirements within the boiler
outercase, pipework should comprise of solder fittings.
3. A 20 °C (36°F) drop in temperature across the system
is recommended for condensing boilers. Existing radiators
may be oversized and so allow this, but where radiator
sizing is marginal it may be advisable to retain a system
temperature drop of 11°C (20°F).
4. In systems using non-metallic pipework it is necessary
to use copper pipe for the boiler Flow and Return. The
copper must extend at least 1 metre from the boiler and
include any branches (Fig. 9).
6.4 Low Head Installation
1. Using a close couple arrangement the minimum head
is as shown in the diagrams (Figs. 10 & 11) subject to the
following conditions:
a) The pump being adjusted to give an 20
across the boiler.
b) The pump must be fitted on the flow.
c) The pump must be fitted in accordance with the
pump manufacturer's instructions.
d) The open vent pipe must be taken up from a tee in a
horizontal section of the flow pipe.
An alternative Low Head Installation
2. For heads below 400mm then a combined vent and
feed pipe may be connected. This must be a minimum of
22mm diameter. It is recommended that an air separator
Flow
is fitted when using a combined feed and vent pipe.
6.5 Thermal Stores
1. When the 100/2 HE Plus is fitted in conjunction with
a thermal store, both jumpers must be removed from
the PCB, see Fig. 32 Section 8.8.
o C drop
(Fig. 12)
11