Mchp Circuit Design - Benchmark mCHP BoilerMate Design, Installation And Servicing Instructions

The (R) models primarily designed for the retrofit market, are fitted with an
automatic bypass valve to allow thermostatic radiator valves (TRV's) to be fitted
to all radiators.The bypass valve is set at the factory to 2m head but this should be
adjusted on site by the installer to ensure that the temperature rise across the boiler
is not greater than 12 o C when the mCHP unit is firing at its maximum rating.
To meet the requirements of Building Regulations for a boiler interlock it
is recommended that the radiator in the area where the programmable
room thermostat is installed should be fitted with lock shield valves on both
connections.
(f) Plastic pipework: All the recommendations with regard to pipework systems in this
manual are generally based on use of BS/EN Standard copper pipework and fittings.
However plastic pipework can be used in place of copper internally as long as it
is recommended by the manufacturer and installed fully in accordance with their
recommendations. We always recommend the barrier plastic pipework for these
systems.
It is important that if the system is to be installed using plastic pipework then ensure
that it is designed and sized for plastic pipework. This is particularly important in
relation to use of push fit connections when using the optional flexible hose kits
(See Installation and Wiring section of this document).
(g) F & E cistern: The cistern available as an option with, can be fitted up to 10m above
the base of the appliance i.e. the maximum static pressure in the appliance must
not exceed 1.0 bar. The water level in the F & E cistern should be at least 250mm
above the highest point on the system including the radiators.
(h) Overflow pipe: The overflow/warning pipe should be in 20mm internal diameter
pipe of suitable material for use in heating systems in accordance with BS 5449
(such as copper). It should have continuous fall and discharge in a conspicuous
external position. It should not have any other pipework directly branched into
it.
(i) Cold feed and open vent: The BoilerMate thermal store acts as the neutral point
of the system. The open vent (22mm copper or equivalent) and the cold feed/
expansion pipe (15mm copper or equivalent) should be run from the BoilerMate
to the expansion cistern as shown schematically in figure 4.1.
Supplied By www.heating spares.co Tel. 0161 620 6677
HEATING AND HOT WATER 4.0
4.3

mCHP CIRCUIT DESIGN

When designing the hydraulic circuit between
the mCHP unit and the BoilerMate, as well as
this manual, the mCHP unit manufacturers
instruc tions should be followed. The
characteristics of the pumps fitted to the
BoilerMate are given in figures 3.4 and 3.5.
The BoilerMate thermal store acts as the neutral
point of the system and therefore this circuit
should be designed such that the open vent
and cold feed/expansion pipes are taken from
the BoilerMate.
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