12
Helpful guidelines
Cold water supplies and storage Recovery of cold storage
Ensure that there is sufficient water recovery to cover the water usage by the appliance.
Aeration of pump and cylinder from a cold water storage cistern
This occurs when the incoming cold mains ball valve is positioned above the cold feeds
to the cylinder and to the pump – aerated water is drawn into the pump as illustrated.
Chronic aeration of the pump occurs when
this problem is combined with inadequate
storage capacity and/or when the volume
of water is drawn by the pump and other
services exceeds the refill rate and creates
a vortex which draws air and possibly
debris into the pump.
Cold storage usable capacity
The usable capacity of cold storage is easily calculated as the capacity of water in the cold
cistern above the cold feeds to the cylinder, the pump and other outlets – see formula.
Formula for calculation on rectangular cistern:
Water above inlet (15”) x width (23”)
x length (36”) = 12,420 cu inches
Volume cu inches (12,420) x 0.01639
= 203.56 litres
Volume litres (203.56) x 0.22 = 44.78
gallons
Outlets
to pump
Vortex
Reposition
cold mains
ball valve here
The bottom
of the cold
tank must
be checked
& cleared
of debris
Widt
h
Length
Depth
of water
Useable capacity
Figure 7: Aeration
Figure 8: Water capacity calculations
Scan QR to find out more