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DESIGN
SY
STEM DET
AILS
Warning/
overflow
pipe
MCWS
Safety/
open vent
Expansion/
cold feed
Figure 1.10
Full bore automatic bypass valve NOT REQUIRED
unless the heating system incorporates
mechanical thermostatic control valves
e.g. T.R.V’s to all radiators or 2 port zone valves.
Primary flow
Primary
return
Boiler
250mm as a
minimum
Head recommended
by boiler manufacturer
as a minimum
6 metres
maximum
F&E cisterns
BMA OV SOL
245 model
Heating System
General
A schematic layout of the heating system in a typical small dwelling is shown above.
The flow and return from the boiler must always run directly to the BoilerMate A-Class
OV SOL and the flow should rise continuously to facilitate venting. The heating circuit is
taken from the BoilerMate A-Class OV SOL and is piped in the conventional manner.
The BoilerMate A-Class OV SOL is only suitable for an open vented system.
The F & E cisterns can be fitted remotely up to 6 m above the base of the BoilerMate A-
Class OV SOL i.e. the maximum static pressure in the store must not exceed 0.6 bar.
The F&E cisterns must be installed at the same level and a typical arrangement is
shown above. If installed in a roofspace, suitable insulation will need to be provided
to the cisterns/any pipework to protect them from damage by frost.
If any radiators are located above the level of the BoilerMate A-Class OV SOL the system
should be designed so that gravity circulation does not occur when the heating pump
is not running. To be certain of preventing this it is recommended that a check valve,
or valves, are fitted on the vertical flow pipes.
The F & E cisterns should be at least 250mm above the highest point on the system
including the radiators and must also be high enough to provide the minimum
head required by the boiler being used.
The boiler manufacturer’s instructions with regard to minimum head must always be
followed. This is particularly important in situations where the headroom is restricted
(e.g. in a flat).
Range rated boilers can be used but should
always be set at the highest output. The
system efficiency will not be impaired while
the recovery rate will be improved.
It is not necessary to provide a boiler bypass on
the primary circuit (i.e. between the boiler and
the thermal store).