Ravenheat RSF 84E Installation And Servicing Instructions - page 14
If the volume of circulating water is too low,
the boiler water temperature will rise too
rapidly. This could cause noise in the sys-
tem or even cause the overheat cut off to
lockout.
4.8.4
Draining tap
These must be located in accessible posi-
tions to permit the draining of the whole
system. The taps must be at least 15 mm
nominal size and manufactured in accor-
dance with BS 2870 1980.
4.8.5
Air release points
These must be fitted at all high points
where air will naturally collect, and must be
sited to facilitate complete fitting of the sys-
tem.
4.8.6
The appliance has an integral sealed
expansion vessel to accommodate the
increase of water volume when the system
is heated. It can accept up to 1.5 gal (7 Its)
of expansion water. If the appliance is con-
nected to a system with an unusually high
water content, calculate the total expansion
and add additional sealed expansion
capacity as appropriate (Fig. 7).
In general modern systems will present no
problem.
Fig. 7
located, between the cistern and the auto-
matic air vent. The stop valve may remain
open during normal operation of the sys-
tem,
if automatic water make-up is
required.
Booster pump method (Fig. 8).
The system may be filled through a self
contained unit comprising of a cistern pres-
sure booster pump if required and if neces-
sary an automatic pressure reducing valve
or flow restrictor. The cistern should be
supplied through a temporary connection
from a service pipe or cold water distribut-
ing pipe. The unit may remain permanently
connected to the heating system to provide
limited automatic water make up.
Mains topping up method (Fig. 9).
Here the temporary connection is supplied
from a service pipe, or distributing pipe,
which also supplies other draw-off points at
a lower level.
A combined double check valve shall be
installed upstream of the draw-off point,
through a temporary hose connection from
a tap supplied from the mains, where the
mains pressure is excessive a pressure
reducing valve shall be used to make filling
easier. The following fittings shall form a
permanent part of the system and shall be
fitted in the order stated.
4.8.7
Mains water feed: central heating
There must be no direct connection to the
mains water supply, even through a non-
return valve, without the approval of the
Local Water Authority.
Permissible methods of filling
Cistern method (Fig. 8).
The system may be filled by one of the fol-
lowing methods. Through a cistern used for
no other purpose, via a ballvalve perma-
nently connected directly to a service pipe
and/or cold water distributing pipe. The sta-
tic head available from the cistern should
be adequate to provide the initial system
design pressure.
The cold feed pipe from the cistern should
include a non-return valve, and a stop-
valve with an automatic air vent connected
between them, with the stop valve being
4.8.8
a) A stop valve complying with the require-
ments of BS 1010 Part 2 (the temporary
hose from the draw off tap shall be con-
nected to this fitting).
b) A test clock.
c) Double check valve of an accepted type.
d) A non return valve of an accepted type.