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Wasser Berlin 2015


Instructions for a correct reading of the meter dial

G2The black digit rolls show the cubic meters (the black color identifies always the measuring unit, regardless the dimension of the rolls), on the other hand the red pointers or the red digit rolls show the submultiples of cubic meter.

In particular the red pointers at the middle of each small dial show the submultiples of the cubic meter: it is therefore possible to read also each liter (0,0001 cubic meter=1 litre). Furthermore the small dial with x 0,0001 on it, has a double division to show a precision up to 1/20 part of the litre.

The dial in the picture shows digit rolls for 4926 cubic meter (the last roll on the right hand side is between numbers 6 and 7, therefore the reading will consider number 6, being the lower) The small dials on the lower part of the dial show:

  1. dial x 0,1: value 4 (being just over the line of number 4) , therefore 0,4 cubic meter, i.e. 400 litres;
  2. dial x 0,01: value 3 (being between 3 and 4), therefore 0,03 cubic meters, i.e. 30 lt
  3. dial x 0,001: value 4 (being between 4 and 5), therefore 0,004 cubic meters, i.e. 4 litres
  4. dial x 0,0001: value 3,5 (being exacly between 3 and 4), therefore 0,00035 cubic meters, i.e. 3,4 decilitre.

Adding up values we will obtain: 4.926,43435 cubic meters.

Usually the utilities supplying water, consider only the cubic meters, without reading the submultiples, after the comma.

To ensure a regular functioning over the time, we recommend to properly install multi or single jet water meters, following these suggestions:

  1. clean thoroughly the two pipe ends, especially if new, where the meter will be installed, ensuring no external particles are in contact with pipes (hempen cloth residuals, calcareous particles, whelding residuals or other) and leave the water running free a little, using instead of the meter an equally long threaded tube, to place between the two pipe ends;
  2. ensure to install the meter towards the same flow direction as the water (please refer to the arrow casted on the meter body);
  3. please install the meter perfectly horizontal and in axis with pipes (avoid any inclined installation that might cause a bad functioning of the meter);
  4. please install the meter in a tamperproof, shockproof place, protected from the wheather conditions, as well as in an easy readable position. We recommend to place the meter inside a specific wide box, which we suggest to insulate from the frost and the wheather conditions by insulating materials;
  5. it is advisable to install the single jet meters immediately downstream pipe networks or any other device that might create water vortex and irregular water flow (any of those will reduce the accuracy of measurement). Where possible, the meter must be installed away from taps, bents, valves, L shaped , at least 10 times the meter diameter and as far as possible from pumps, autoclave...;
  6. we recommend to install the meter between 2 stop valves or taps, in order to close it off in case of dismantling for maintenance or replacement. It is advisable that the tap downstream can discharge, in case of pipes to empty for maintenance or in case of frost), or in case it is necessary to check the meter well functionings. If possible, please use upstream full open valves (to be kept constantly opened) or follow the above mentioned rule of 10 times the distance from the upstream tap;
  7. we recommend to ensure that the meter is always full of water (both when working and when not working), in order to maintain the components in good working conditions; the only exceptions are for a short time, for instance, due to maintenance reasons). When opening the water inside the network (the first time or after emptying it), please pay attention to let the water flow slowly, to avoid any damage to the meter.

To install Woltmann meters on pipes with a different size from that of the meter, it is necessary to use specific tapered flange adaptors, keeping a straight pipe section both up and down stream with a minimum length of 10 times the nominal diameter of the meter (DN).

To ease the installation and a possible removal of the measuring instrument from the fixed pipes, we recommend to use mobile joints downstream the meter.


please remember that Woltmann meter with vertical helical vane is only suitable for horizontal installation; we recommend to install a removable Y strainer upstream the meter.

Before installing the meter, it is advisable to well clean pipes.

Firmly avoid whelding counterflanges to the meter,once installed.

Firmly avoid to install meters close to pumps.

Any abrupt change in cross-sectional area or any bent or any L-shaped pipe upstream the meter, causes a vortex movement, which in turn influences negatively the measurement accuracy, whilst any of those immediately downstream the meter, do not influence the accuracy, but might wear the helical vane, through the water flowing against the meter. Therefore we recommend, where possible, to have downstream the meter a straight pipe at least 5 times the meter size (DN), or even more if possible.

In presence of gate valves upstream the meter, we recommend to leave a distance of at least 12 times the meter size (DN); only when the gate valve is constantly open, the distance can be reduced to 4-5 times the meter size; vertical helical vane meters require only 2 times the meter size.

In presence of non return valves, we recommend at least 12 times the meter size (DN).

In presence of T- couplings or T bents upstream, it is necessary to install a flow straightener, or to leave a straight pipe section of at least 25 times the meter size (DN), and for vertical helical vane meters at least 03 times the meter size (DN), also when the bents and T-couplings are on the same level.

The drainage must be on a upper level as to the meter, so that the latter is always full of water, to avoid that any functioning of the meter without water might would damage the helical vane and the lower mechanism, as well as to avoid any air bubbles growing inside the pipe network.

For maintenance or cleaning, the internal mechanism can be removed from the body, which remains installed on the pipe. Please ensure that no external particle gets inside the pipe or inside the meter body, by protecting the internal mechanism open hole.

In case the meter should be removed completely, it is necessary to have a flanged removable device to replace the meter with.


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