Replacing The Diaphragm; Dismounting The Diaphragm; Mounting The Diaphragm - GF Diastar Eco Bedienungsanleitung

Maintenance

5.2 Replacing the diaphragm

The component with the most wear and tear in every diaphragm valve is the diaphragm itself.
Besides mechanical stress, the diaphragm is subject to wear resulting from the flow media.
We therefore recommend inspecting the diaphragm at the latest after 100,000 cycles at 20°C,
with nominal pressure and water. If the flow medium has higher temperatures, other
chemicals or abrasive particles, we recommend more frequent inspections. The diaphragm
can be checked by dismantling the valve body.
5.2.1

Dismounting the diaphragm

 Drain and de-pressurize the pipeline
 Move the valve into the "OPEN" position with the control medium (FC, DA)
 Dismantle the valve body by removing the screws which connect the valve body to the
intermediate piece
 Elastomer diaphragms
o Elastomer diaphragms DN15, DN20 have a pressed knob on top. To remove
the diaphragm, just pull strongly
o Elastomer diaphragms DN25 to DN50 are retained by a threaded bolt and are
removed by rotating counterclockwise
 PTFE diaphragms are equipped with a bajonnet catch. Rotate the diaphragm 90° in any
direction and pull out
5.2.2

Mounting the diaphragm

 Work in the reverse order to that indicated in 9.2.1
 However, only tighten the screws until the valve body is butt against the diaphragm.
 Move the valve into the "CLOSED" position with the control medium
 Put the valve in the "OPEN" position again with the control medium (FC, DA)
 Tighten/retighten the screws with the torque in the table below
 For valves with a built-in stroke limiter, we recommend readjusting the valve after the
replacement
d (mm)
20
25
32
40
50
63
56
DN (mm)
15
20
25
32
40
50
Inch
1⁄2"
3⁄4"
1"
1 1⁄4"
1 1⁄2"
2"
Instruction Manual
Torque (Nm)
2.5
3
4
6
10
15