17
Pre-installation
Installation
PumpWise guidelines
General specification
Trouble shooting
PumpWise and warranty
Pump hunting protection
In negative head systems all the discharge
pipework after the pump is pressurised. In
such systems there exists the possibility
the pump will hunt ON-OFF-ON etc at
intervals.
This will happen:
• if all outlets are not fully closed
• if there is a leak at a connection
• if boosted toilets are not fitted with
equilibrium ball valves
• or as residual hot water contracts in
long pipe runs.
The irritating effects of hunting are
cushioned by the pressure vessel which is
an inbuilt feature of Right Universal pumps.
Stored hot water volume
In calculating the volume of the stored
hot water requirement it is important to
consider:
• number of bathrooms, with particular
attention to the size of the bath
• number of persons in household
• time spent in shower e.g. 10mins in a
5 gall/minute shower will use up 50
galls/227 Litres of the cold water
storage capacity approx 60% of which
(30 gallons/136 Litres) will be hot water
from the cylinder.
Stored hot water temperature
Extract from BS5546:1990 (Current)
“The mean temperature of the stored water
should not normally exceed 60°C and in a
combined central heating and domestic
Vent
and other
services
HWS Blending valve controller
is factory set at 55 – 60ºC
Not for RSP/RHP
or ESP
Can be off the vent
if this distance is
at least 1.5 metres
Usable capacity
minimum 50 galls
per bathroom
Surrey or
No Stop
Essex Flange
C
H
Fig 29 HWS Blending
OLD STYLE DO NOT USED
MAX
60˚C
Vent
and other
services
HWS Blending valve controller
is factory set at 55 – 60ºC
Not for RSP/RHP
or ESP
Can be off the vent
if this distance is
at least 1.5 metres
Usable capacity
minimum 50 galls
per bathroom
Surrey or
No Stop
Essex Flange
H
C
hot water system it is recommended that
the stored water temperature is controlled
independently from that on the primary
circuit”.
Extract from BS6700:1997
“Under normal conditions the
temperature of stored hot water should
never exceed 65°C. A stored hot water
temperature of 60°C is considered
sufficient to meet all normal requirements
and will minimise scale deposits in hard
water areas”.
Effective control of stored hot water
is simply achieved by use of a cylinder
thermostat and zone valve or direct acting
thermostatic valve (e.g. tapstat).
In systems where the stored hot water
temperature is not controlled eg Aga solid
fuel appliance or very crudely by the boiler
thermostat, use a HWS Blending valve
controller.
HWS Blending valve controller
The HWS Blending valve controller is
designed to protect booster pumps in