## CHOOSING THE RIGHT SURFACE PUMP

Step 1

### Just answer the following four questions

*Question 1 : *What is the suction depth ?

*Answer :* 4 m

*Example : *The water is roughly 4 m lower than the pump

*Question 2 : *How long is the sprinkler pipe ?

*Answer :* 6 m

*Example : *60 meters of pipe

Head loss* is estimated at 10 % of the overall pipe length, so count

*Question 3 : *What is the height difference between the pump and the water outlet ?

*Answer :* 8 m

*Example : *The water outlet(s) are roughly 8 meters higher than the pump 8 m

No matter how many water outlets there are**, we consider at least 2 bar of outlet pressure necessary for proper working.

2 bar is the equivalent of 20 m head, so count

YOU THEREFORE REQUIRE A TOTAL DELIVERY HEAD OF : 3.8 bars / 38 m

*Question 4 : *How many water outlets are in use ?

(garden sprinkler and/or hosepipe, tap, WC, shower, washing machine, etc.)

*Example : *2 water outlets

Assuming a water outlet delivers an average 1 cubic meter per hour (m^{3}/h)

YOUR OUTPUT REQUIREMENT IS 2 m^{3}/h – 2 000 l/h

**PLEASE NOTE** : For a pump at the bottom of a well, the calculation is the same but with a suction height of zero.

** : water flowing in a pipe loses pressure (frictional head loss). The estimated loss in a 19 mm (3/4 ”) pipe is 10 %. *

* ** : A pressure of 2 bar (20 m head) is considered necessary for a water outlet to work properly. *

* No matter how many outlets there are, the required pressure will always be 2 bar, as pressure is not additive. *

Step 2

### Now look at the product performance graphs

**Once you have established the flow rate and pressure, all you have to do is look at the graphs for each TECNOMA pump** and choose the pump whose curve passes through or close to the point where your two values intersect.

*Example :* head 38 m, output 2 m^{3}/h

The PULSAR 1300 pump curve goes though this point.

This calculation does not affect your choice of whether to use a manual start-stop, top-up, or automatic booster pump ; the type of pump is purely dependent on the use you make of it (automatic or not, domestic use, etc.).