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4. Discharge piping
(1) Pipe diameter
In case the discharge piping is long, the specified performance may not be obtained because of unexpected pipe
resistance if the pipe diameter is the same as pump bore. Calculate the pipe resistance in advance to decide proper
diameter of pipe.
(2) Position of the first valve
Take 1m or so distance between pump and the valve located the nearest to pump and install air eliminating piping
at the place close to the nearest valve to the pump so that air can not remain in pump. Refer to “Example of recom-
mended piping” on page 10.
(3) Gate valve
Install the gate valve in discharge piping to adjust flow rate and to protect motor from over loading. If the check
valve is also installed, recommended arrangement is : Pump
/
Check valve
/
Gate valve
(4) Pressure gauge
Install a pressure gauge in discharge piping to check the operating conditions such as discharge head etc.
(5) Check valve
Check valve must be installed in the following cases.
•
Discharge piping is longer than 15 to 20 meters.
•
Actual head exceeds 15 meters.
•
Height difference between liquid level and discharge pipe end exceeds 9 meters.
•
When two pumps are used in parallel.
(6) Air vent
If horizontal discharge piping is longer than 15 to 20 meters, install air vent on the way.
(7) Drain
If the liquid must be drained to protect from freezing, install the drain valve.
(8) Pipe support
Install the pipe support so that the pipe weight can not be loaded to pump.
(9) Priming piping
Install piping for priming in case of suction lift.
3. Electrical wiring
Electrical works or wiring must be carried out by qualified and authorized person according to local law or regulation.
•
Use the electromagnetic switch which conforms to motor specifications such as voltage and capacity etc.
•
If pump is installed outdoor, wiring must be done so that water can not get into switch.
•
Electromagnetic switch and push-button switch must securely installed apart from the pump.
