D E S C R I P T I O N
INTRODUCTION
The PulsaCoil III based hot water supply system is shown
schematically in Figure 1.1.
The PulsaCoil III appliance utilizes an off peak electrically
heated thermal store with integral feed and expansion
cistern to produce primary hot water. This is then
circulated by a pump through a plate heat exchanger to
instantaneously heat mains pressure domestic cold water.
This allows mains pressure domestic hot water to be
provided to the taps at high flow rates without the need
for any temperature and pressure relief safety valves or
expansion vessels. The actual temperature of the
domestic hot water is maintained at the pre-set level by
a printed circuit board which controls the speed of the
pump circulating the primary hot water from the store
through the plate heat exchanger.
THERMAL STORE
The thermal store and the top up cistern are constructed
of copper. The thermal store is manually filled with mains
cold water through the feed and expansion cistern. It
should be filled up to the level of the swage mark in the
cistern.
The thermal store is efficiently insulated with Rockwool
CFC free insulation and finished in a painted steel case
to minimise standing losses.
The primary water in the store is heated to a temperature
of approximately 77
o
C by the immersion heaters.
2
DOMESTIC HOT WATER
Cold Water Supply
The PulsaCoil III units are designed to be fed directly
from the mains water supply as shown schematically in
Figure 1.1. They fulfil the requirements of Water Bylaw
91, and therefore do not require a check valve to be
fitted to the supply pipe. The performance of the PulsaCoil
is directly related to the adequacy of the cold water supply
to the dwelling. This must be capable of providing for
those services, which could be required to be supplied
simultaneously, and this maximum demand should be
calculated using procedures defined in BS 6700.
PulsaCoil will operate at mains pressures as low as 1
bar and this must be available when the local demand is
at its maximum, but the preferred range is between 2
and 3 bar. As a general guideline, although a 15mm
external service may be sufficient for smaller dwellings
with one bathroom, a 22mm service (25mm MDPE) is
preferred and should be the minimum for larger dwellings.
If a water meter is fitted in the service pipe, it should
have a nominal rating to match the maximum hot and
cold water peak demand calculated in accordance with
BS 6700. This could be up to 50
litres/min in some
properties.
The unit must be fitted strictly in accordance with the
requirements of the Local Water Undertaking who should
be consulted prior to the installation. In the event of any
difficulty please contact us as the manufacturers. The
equipment used in the system should be suitable for a
working pressure of 8 bar and approved by the WBS or
other relevant standard. If this is not the case a pressure
limiting valve will be required which is suitable for the
item of equipment with the lowest maximum working
pressure.
Supply
pipe
Second
dwelling
H
a
a
C
a
C
H
a
a
C
Sink
Hand
basin
Bath
Shower
Check valve NOT REQUIRED unless supply
pipe services more than one dwelling
Check valve NOT REQUIRED unless
chemical water treatment unit is fitted
Scale inhibitor
NOT REQUIRED
Mixing valve
Lockshield gate valve recommended
for maintenance/flow control in high
pressure areas.
Figure 1.1 Typical hot and cold water distribution network
‘a’ - flow regulator recommended for better
balance of hot and cold water supply
Pressure limiting valve
NOT REQUIRED at pressures
below 8 bar unless any system
components have a lower
maximum working pressure.
