18
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 the Right pump universal range.
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 BS5546:2010 (Current)
“
The mean temperature of the stored water
should not normally exceed 60°C and in a
combined central heating and domestic
hot water system it is recommended that
the stored water temperature is controlled
independently from that on the primary
circuit
”.
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 systems where
the temperature of the stored hot water is
uncontrolled. (Figure 17, P14)
Summary of Contents for Right Pump Series
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