joule Thermalstore 1.0, Installation Manual

Page: 11 / 68

11
PRIMARY CONNECTIONS
The JOULE Thermalstore has 9 direct tappings for the integration of the heating
system with the DHW, allowing for numerous heat sources to combine in an
extremely effi cient manner to generate DHW and space heating.
The boiler or boilers may be Gas, Electric, Oil, Solid Fuel, Biomass, Solar, or a
combination of a number of these.
SECONDARY CIRCULATION
On larger installations long pipe runs to dr aw-off points can cause signifi cant
volumes of water to be drawn off before an acceptable temperature can be
reached. Secondary pumped circulation using a stainless steel or a bronze pump,
and combined with eff ective time and temperature controls can overcome this
problem. Where secondary return circulation is required the pipework should be
run in 15mm pipe. A suitable WRAS approved stainless steel or bronze circulation
pump must be used. A check valve must also be installed to prevent backfl ow.
On large secondary circulation systems it may be necessary to incorporate an extra
expansion vessel into the circuit to accommodate the increased system
water volume. It should be noted that the use of a secondary circulation circuit can
increase running costs as there will be circulation pipe losses. High levels of insula-
tion on secondary pipework are required to keep energy losses to a
minimum.
DEAD LEGS
The length of hot water draw off to taps and other outlets should be kept to a min-
imum to reduce the amount of cold water drawn off before the hot water arrives.
The maximum recommended dead leg lengths are shown in fi gure 2.b. Where there
is more than one size of pipe on a dead leg, the equivalent length and size should
be estimated.
Where the dead leg length exceeds the recommended maximum, secondary circu-
lation should be installed. It should be controlled by a time switch and
incorporate a motorized valve that can prevent gravity circulation in the circuit.