Rayburn Heatranger 480GB Installation Instructions Manual - Site Requirements
The following items are of particular importance:- In a
combined central heating and domestic hot water
system, the hot water storage vessel MUST be of the
indirect cylinder or calorifer type.
The hot water storage vessel should be insulated
preferably, with not less than 75mm thick mineral fibre, or
its equivalent.
Pipework not forming part of the useful heating surface
should be insulated to prevent heat loss and possible
freezing, particularly where pipes are run through roof
space and ventilated under floor spaces. Cisterns situated
in areas which may be exposed to freezing conditions
should also be insulated.
The bypass balancing valve should be of a type non-
adjustable by the householder and must have at least 2.5
metres of 28mm pipe each side between it and the
cooker burner.
Alternatively the bypass loop can incorporate a towel rail,
controlled by a non-adjustable balancing valve.
The bypass loop must not be insulated.
Draining taps must be located in accessible positions
which permit the draining of the whole system, including
the appliance and hot water storage vessel.
The appliance boiler section should be connected to
cistern water supply, subject to a maximum heat of 2 bar
(20m), minimum of 0.1 bar (1m).
The heating system must be designed (and adjusted if
necessary) to give a temperature differential across the
boiler at full output of 10˚C - 14˚C. The use of horizontal
pipe runs should be avoided wherever possible in order to
prevent the collection of air in the system. If horizontal
runs are unavoidable, the pipes should rise upwards in
the direction away from the appliance.
Circulating Pump
It is recommended that the selected pump be sized to
suit the boiler pressure loss (see Fig. 1) and therefore
adequate to give the required temperature differential
between the flow and return.
The pump should be able to meet the requirements of
the system design and fitted in a readily accessible
position.
Isolating Valves
Isolating valves (preferably of the keyless type) must be
fitted to the inlet and outlet of the circulation pump to
facilitate service and replacement of pump without
draining the system.
Inhibitor.
A corrosion inhibitor MUST be added to the heating
system to protect the heat exchanger and pipework.
Inhibitor must also be replaced if the system is drained
after installation. As a precaution the heating system
MUST also be flushed out prior to the addition of the
inhibitor to ensure any flux, debris is removed.
Site requirements
9
WATER CIRCULATION SYSTEM
FIG. 3