Potterton Promax System HE Installation And Servicing Instructions page 10

Boiler
Fig. 8a
10
Copper
Copper
0.5m
0.5m
Copper
1m
6.0 System Details
6.3
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 22mm (copper tail).
Flow
2. Due to space requirements at the rear of the tap
Return
bracket, 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. 8a).
6.4
1. For optimum operating conditions, the heating
system into which the boiler is installed should
include a control system.
2. Such a system will comprise of a timer control
and separate room or cylinder thermostats as
appropriate.
3. The boiler should be controlled so that it
operates on demand only.
4. Operation of the system under control of the
boiler thermostat & TRV's only does not produce
the best results.
6.5
1. When the Potterton Promax System HE is fitted
in conjunction with a thermal store, jumper 2 must
be removed from the Control PCB, see Fig. 32a
Section 8.7.
Pipework
System Controls
Thermal Stores