Installation Guide

15
Connection to boilers
Speedfit pipe should never be connected
directly to a boiler.
Although most modern boilers have a high limit
thermostat, residual heat can be conducted by the
heat exchanger. Therefore, Speedfit recommend a
minimum of 1 metre from the boiler casing should be
run in copper pipe unless otherwise stated in the
boiler manufacturer’s installation literature.
A gravity primary circuit operating on an uncontrolled
cooking range or solid fuel boiler should be run entirely
in copper and the heating circuit run in copper for the
first metre. Refer to BS 5955: Part 8 for further clarification.
All appliances should have safety devices to make sure
they cannot operate above the working temperature and
pressure range set out in our Technical Checklist on page
23. If safety devices are not incorporated within the
appliance then external controls will be needed.
Water meters (and other devices) can contain check
valves that prevent the expansion of heated water back
down the main supply from a combi boiler. If plastic pipe
is to be used, a suitable expansion vessel must be fitted.
This is especially important to consider if a water meter is
fitted retrospectively. Speedfit do not recommend the use
of plastic pipe on the main supply between a water meter
and a combi boiler if an expansion vessel is not fitted.
Speedfit products should not be fitted to a sealed
system oil boiler, a back fired boiler or other uncontrolled
heat source.
Please also see Drop-pipe systems on page 16 and
System commissioning and flushing on page 21.
Continuously operated
re-circulating systems
(secondary hot water circulation/
ring main installations)
A continuously operated re-circulating system is a
water-replenished circulating system which is maintained
at a constant high temperature to provide a constant
source of hot water. Continuously operated re-circulating
systems are used to distribute constant hot water to
draw o points that may be distant from the source
or hot water storage vessel.
Continuously operated re-circulating systems are
very dierent from conventional hot water supply and
central heating systems found in domestic properties,
for which our products have been tested to, under either
BS7291:2010 Class S or WRAS approval standards,
and for this reason Speedfit products must not be used
on any continuously operated re-circulating systems as
they are not approved under the current version of
these standards.
Unvented pressurised cylinders
Unvented pressurised cylinders can be installed
using Speedfit pipe and fittings. However if the safety
parameters of the cylinder exceed those of the pipe and
fittings it is possible to fit a pressure reduction valve on
the out going hot supply pipe. This will not interfere
with any other cylinder safety devices demanded by
regulations as they are all fitted in the incoming side
of the cylinder.
Run a short length of copper pipe from the cylinder
connection (about 150mm – 300mm) then fit a suitable
pressure reduction valve. This will protect the pipe and
fittings from excessive pressure in the event of boiler/
cylinder malfunction. The factory fitted temperature/
pressure relief valve on the cylinder will discharge
below 100°C therefore protecting the pipe from
excessive temperature.
Connection to cylinders
and water heaters
Speedfit can be used on sealed and open vented heating
systems, where boilers are either heating a hot water
storage cylinder or instantaneous hot water such as
a combination boiler. The temperature and pressure
limits of the system must not exceed the maximum
values stated under the heading ‘Working Temperatures
and Pressures’.
When using a traditional copper vented cylinder
Speedfit pipe and fittings can be installed with direct
connections to the cylinder. Unvented pressurised
cylinders can be installed using Speedfit pipe and fittings.
However, insertion depths on compression joints that
form part of the cylinder must be checked prior to
installation and the use of standard pipe inserts (Prefix
TSM) is recommended.
Speedfit connections to combined cylinder/boiler units
and thermal storage units must be made outside the
casing unless otherwise stated in manufacturers
installation literature.