Maintenance; Troubleshooting - Yoshitake GD-27BP Product Manual

8.1 Troubleshooting

(See "4. Structure" on Page 6 and "9. Exploded view" on Page 16.)
Trouble
Reduced pressure
rises and exceeds set
pressure.
Pressure does not
reach the desired
value.
Outside leakage
Abnormal sound
 Most of problems with the pressure reducing valve are caused by foreign substances and scale in the
piping. Avoid the ingress of dust and dirt to the product with caution.
 A phenomenon similar to valve failure could occur due to the failure of the pressure gauge, clogging of
the strainer, and other causes. Check the above possible causes and take a proper remedy and
preventive measures.

8. Maintenance

Cause
1. There are foreign substances stuck
between disc [12] and valve seat
[3], or scratches on them.
2. O-ring [8] is damaged.
3. Diaphragm [16] is damaged.
4. Packing at ball valve part is worn or
damaged.
5. By-pass function is set.
1. Working pressure is improper.
2. Nominal size of the product is too
small for the flow rate for use.
3. Pressure adjustment is improper.
4. Strainer at inlet side of the product
is clogged.
5. Domed cap nut [40] is loosened.
6. Stop function is set.
1. Bolt [38] is loosened.
2. Plug [41] is loosened.
3. Plug [42] is loosened.
1. Nominal size of the product is too
large for the specifications.
2. Pressure reduction ratio is too
large.
3. Air binding has occurred.
4. Quick operating valve is located
near the product.
1. Disassemble the product and remove
the foreign substances. If scratch is
observed on disc [12] or valve seat
[3], replace it.
2. Replace O-ring [8].
3. Replace diaphragm [16].
4. Please contact us.
5. Switch the functions.
1. Change to appropriate value. (See
"2.1 Specifications" on Page 1.)
2. Replace the product with the proper
nominal size. (See "2.2 Nominal size
selection" on Page 2.)
3. Readjust the pressure in accordance
with the given procedure. (See "7.2
Adjusting procedure" on Page 10.)
4. Clean the strainer.
5. Tighten domed cap nut [40].
6. Switch the functions.
1. Tighten bolt [38].
2. Replace plug [41].
3. Tighten plug [42].
1. Replace the product with the proper
nominal size. (See "2.2 Nominal size
selection" on Page 2.)
2. Reduce pressure in two stages. (See
"2.1 Specifications" on Page 1.)
3. Install an air vent device.
4. Keep a distance between them as
large as possible (3 m at least).
11
Remedy
EPDT-278