Davey PRIME JET 240 PUMPS AND PRESSURE SYSTEMS - Manual (Page 4)

INSTALLING A PRIME JET FOR ‘DEEP WELL’ APPLICATIONS
(Total Suction Head over 7.5m or 25 ft) with Deep Well
Injector Kit.
The Deep Well Injector Kit comprises a bronze injector and foot
valve assembly which is to be attached to the end of polythene
piping and lowered into the water. An adaptor flange (or bend) to
connect the suction pipes to the pump is also included in the kit,
together with a rubber gasket and 2 polythene connectors and 8
stainless steel hose clips.
(A) Piping for use on Deep Well Injectors
All Deep Well Injectors require two pipes to be connected. Pipe
sizes are according to Table below (except where special sizes
may be specified for a particular installation).
DEEP WELL SUCTION PIPES DEEP WELL SUCTION PIPES
INJECTOR KIT I.D. INJECTOR KIT I.D.
100mm (4”) 125mm (5”)
427 & 428 1 1 /
2
” (38mm) & 565, 567, 568 2” (50mm) &
1 1 /
4
” (32mm) 569 1 1 /
2
” (38mm)
NOTE: Injector fittings are sized for imperial pipe.
Polythene piping which complies with the relevant Australian Standard should be used. Select the
grade of pipe which has a pressure rating of 90m head (300 ft.) for use on depths over 12 metres
(40 ft.). For depths up to 12 metres (40 ft.) polythene pipe with a pressure rating of 60m head
(200 ft.) may be used.
For “Offset” installations involving long runs of pipes to the deepwell injector, larger sized pipes
will be required to minimize resistance to flow and enable pump performance to be achieved.
Consult your Davey Pump Dealer or the Davey Customer Service Centre for recommendations.
AUTOMATIC DEMAND RESPONSE VALVE
Included in the Deep Well Injector Kit carton is the automatic demand response valve (ADR). The
ADR should be fitted to the discharge elbow of the pump. A gate valve must be fitted to the ADR
outlet before connection of the outlet piping. For ease of setting the ADR (see page 10) provision
must also be made to allow for temporary full open discharge of water after the gate valve.
OPERATING INSTRUCTIONS
OPERATING THE PUMP
(A) Shallow Well Installations
Close gate valve at outlet of pump. Remove the priming plug and fill pump body and suction
pipe by pouring water into the priming port on top of the pump or open gate valve on supply
reservoir to allow water to flow into pump. Air will be expelled as the suction pipe is filled with
water.
When all the air has “bubbled” out replace the priming plug. Do not run the pump without
water.
Switch on power to pump.
Crack air bleed screw on priming plug to expel trapped air.
Allow pump to run until a change in sound of pump indicates that prime is established and
pressure gauge reading rises to over 350 kPa.
Open gate valve at pump outlet.
A strong flow of water should be evident at an outlet tap indicating pump is functioning. If there
is no strong flow of water at the outlet tap or the pressure gauge reading drops away, reprime
the pump and repeat.
On long suction lines it may be necessary to re-prime several times to expel all the air from
the suction line to allow the pump to operate efficiently.
To Check Correct Operation of a Pressure System with Pressure Tank Fitted
Close gate valve at pump outlet. Allow pump to run and build up pressure until it switches off
automatically at the cut-out pressure setting of the pressure switch. Open gate valve on pump
outlet then turn on a tap in the outlet pipework. Pump should automatically switch on at cut-in
pressure setting.
(B) Deep Well Installations
Ensure both suction pipes are full of water and all pipe connections are well sealed.
Fill pump by pouring water in at priming port on top of pump. Replace priming plug when all
air has “bubbled” out. Crack air bleed screw to expel trapped air.
Switch on power to pump.
Close gate valve at outlet of pump.
If correctly primed, pressure gauge reading will quickly climb to over 350 kPa.
On deep well installations it may be necessary to reprime several times to expel all the air in
the pipes.
Once prime is established slowly open gate valve at pump outlet.
A strong flow of water should be evident at an outlet tap indicating pump is functioning.
On OFFSET deep well installations the suction lines may not rise evenly from water source to
pump and so trapped air in a hump will prevent priming. A tee installed at the highest point in
both pipes may be used to add water at this point provided that it is well sealed and air tight
before pump operation.
NOTE: The use of an engine powered pump to force water up the suction pipe
from the water source may simplify priming long suction lines.
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