Glow-worm Ultimate 30BF - Manual (Page 9)

9 221788B
3 Water Systems
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 control thermostat set at “MAX”, which is about
82
o C (180 o F).
The resistance through the boiler can be found from diagram 3.1.
High resistance microbore systems may require a higher duty
pump.
3.3 Bypass - Fully Pumped Water System
A bypass is usually unnecessary on systems using a 3 port
diverter valve since one port will remain in the open position at
all times. This allows satisfactory operation of the pump
overrun.
However if thermostatic radiator valves are fitted to all radiators
or two port valves are used a bypass is required.
The bypass connection must be at least 2 metres 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 the
flow and return.
3.4 Water System
The cold feed must be 15mm minimum size.
It is important that the relative positions of the pump, cold feed
and open vent are as shown in diagram 3.2.
The unrestricted open vent from the boiler must rise continuously
to discharge over the feed and expansion cistern.
Water pressure loss (mm head of water)
Flow rate (litres/minute)
0 5 10 15 20 25 30
0
250
500
750
1000
PRESSURE LOSS OF BOILER
4631
Diagram 3.1 Diagram 3.3
3794
Note: When cutting leave
sufficient length for fittings
COMPRESSION
JOINT
22mm
PIPE
28mm
PIPE
FLOW (GRAVITY) RETURN
FLOW
28mm
PIPE 22mm
PIPE
HEATING
SYSTEM
PUMP
VIEWED
FROM
FRONT
28mm
1m MIN.
27m MAX.
INDIRECT CYLINDER
(Shown with
recommended
thermostat and valve)
15mm COLD FEED
22mm VENT
REFER TO BS5546
RETURN (GRAVITY)
6455
FEED AND
EXPANSION
CISTERN
22mm VENT
(MIN.)
15mm (MINIMUM)
COLD FEED
OPEN VENTED FULLY PUMPED WATER SYSTEM
RECOMMENDED RELATIONSHIP BETWEEN
PUMP COLD FEED AND VENT
450mm
MIN.
HEIGHT
1150mm
MIN.
RETURN FLOW
CYLINDER
PUMP
HEATING
150mm
MAX.
BOILER
IF REQUIRED
15mm (MINIMUM)
BY-PASS WITH
LOCKSHIELD VALVE
FLOW
RET.
There must always
be a cold water path
to the return
connection
of the boiler.
Diagram 3.2