E-RM 30
Installation and service manual
M2016/09f[EN]
8. W
ATER
METERS
8.1. C
HOOSING
THE
RIGHT
WATER
METER
SIZE
The main criterior for choosing the right water meter size (nominal diameter) should always be the water
meter working conditions, that is the average and maximum value of a passing water working flow.
When a water meter is too large, it does not increase the investment cost, but also has lower accuracy in
case of small water flow. A too small water meter can cause its overload and sumiltaneously quicken the
wear of its active parts.
It is recommended to choose the size of the water meter so that the size of the largest expected jet flow in
the system between 0,45 and 0,6 of the water meter constant jet flow Q
3
.
8.2. W
ATER
METER
JS
8.2.1. Single jet dry type water meter
Single jet dry type water meter consists of two basic units: measurement unit and counting mechanism. The
main elements of the measurement unit are: a body with a sieve places in an inlet channel, a vane, a sealing
plate. Main components of a counting mechanism are: a gear set, a roll set and a counter cover. The
mechanism is attached to the unit by means of fastening ring and after legalisation, sealed with lead.
Single jet water meter vane is propelled by a jet of water which pushes ifs blades along the vane perimeter
and it is the only movable element submerged in water. Rotor rotation is conveyed by a magnetic head
clutch, through the sealing plate. Dry counter, sealed air-tight in separete module, sums the flow of measured
water and displays the result in digital, easy to read manner. Counter is fitted with a motion detector which
makes it possible to automate regulation and legalisation.
The regulating device is protected from tampering by a lead seal. Thanks to a special design of rotor
bearings and the choice of corrosion and abrasion resistant materials, the water meter is characterised by
high durability.
8.2.2. Parameters
Type
cold water
warm water
JS-1,6
JS90-1,6
JS-2,5
JS90-2,5
JS-2,5-G1
JS90-2,5-G1
JS-4
JS90-4
Nominal diameter
[mm]
15
20
Permanent flow rate Q
3
[m
3
/h]
1,6
2,5
4
Overload flow rate Q
4
[m
3
/h]
2
3,125
5
Minimum flow rate Q
1
(horizontal / vertical installation)
[dm
3
/h]
16 / 32
20 / 40
25 / 50
31,25 / 62,5
40 / 80
50 / 100
Transition flow rate Q
2
(horizontal / vertical installation)
[dm
3
/h]
25,6 / 51,2
32 / 64
40 / 80
50 / 100
64 / 128
80 / 160
Maximum permissible error
(Q
2
to Q
4
)
±2 %
±3 %
Measuring range R (Q
3
/ Q
1
)
(horizonral / vertical installation)
100 / 50
80 / 40
Max. working temperature
[°C]
30
90
Max. working pressure
1,6 MPa (16 bar)
Lenght
[mm]
110
130
Conformity
MID, EN 14154, OIML R49
* For water meters DN 15, Q
3
= 2,5 m
3
is also possible to order a water in lengh L=80 or L=115
(input/output =
7/8
/
3/4
“ pro L=115)
13 / 17
