Stuart Turner Showermate U1.8 bar Twin - Manual (Page 7)

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2.27 Non-preferred pump location: If it is not possible to locate the pump in the
preferred area due to site limitations and it is necessary to position the unit in the
loft, or in a position above the secondary tapping that feeds the pump, then there
is an increased risk of air locks. This risk must be eliminated.
The following measure is a suggestion that may overcome the problem:
Always use an Essex or side entry flange as the hot pump connection and a
“U” bend or downward loop in the supply pipe to the pump of 350 mm depth
before rising to the pump should ensure the cylinder vents its air up the
expansion pipe, not up the pump feed (Figs. 3 & 4).
2 LOCATION - SINGLE PUMP
Max. inlet head
6
m
Min. inlet head
0.5
m
hot water
services
Negative head
200
mm
min
350
mm
Max. outlet head
6
m
least preferred area
Fig. 4 - Twin Pump
Max. inlet head
6
m
Min. inlet head
0.5
m
Negative head
200
mm min
350
mm
min
Max. outlet head
6
m
least preferred area
Fig. 3 - Single Pump
Negative Duty Single Pump System
Fig. 5
Max. static inlet pressure
6
m