7
220683B
The installation of the boiler must comply with the
requirements of the current issue of BS6798.
3.1 Frost Protection
If the position of the boiler is such that it may be
vulnerable to freezing it should be protected as specified
in the current issue of BS5422. It is recommended that a
frost protection thermostat be fitted.
3.2 Pump
The pump, with integral valves, should be fitted in the
heating flow pipework from the boiler, it should be set to
produce a temperature difference of 11
o
C (20
o
F) between
the flow and return, with the boiler thermostat set at
“MAX”, which is about 82
o
C (180
o
F).
The pressure loss of the boiler can be found from
diagram 3.1.
High resistance microbore systems may require a higher
duty pump.
3.3 Bypass - Fully Pumped and Sealed
Water System
A bypass MUST be fitted to a fully pumped and sealed
water systems.
Where the water system allows the boiler and pump to
operate on bypass only, the bypass connection must be at
least 2.5metres away from the boiler.
The flow through the boiler must not be allowed to fall
such that there is a temperature difference greater than
20
o
C between flow and return.
3 W a t e r S y s t e m s
1000
750
500
250
0
0
5
10
15
20
25
30
Flow rate (litres/minute)
Water pressure loss
(mm head of water)
PRESSURE LOSS
OF BOILER 80FF
0088(a)M
30.6
litre/min
Design Flow Rate
The intersection point indicates the Flow Rate
required to achieve 11
0
C temperature difference.
Diagram 3.1
PRESSURE LOSS OF BOILER
30.6
LITRE
/
MIN
