Page 5 of 10
6.
Maintenance and repair of safety valves
In order to ensure correct operation of safety valves, the following conditions must be meet:
valve disc cannot set slantwise to the valve seat
sealing surfaces of the seat and disc should ensure tight closure of the valve;
All cooperating moving parts of valve mechanism should maintain movability in operating conditions.
In order to maintain these conditions the valves should be periodically inspected and renovated. Inspections of
safety valves should be conducted by persons with adequate authorisation. While the repairs should be first
carried out by the manufacturer of the safety valve or at authorized service centres, or by the user’s service
teams having appropriate permissions
ATTENTION
In addition to the recommendations included in these instructions, the requirements and recommendations
resulting from the surveillance provisions of the country in which safety valve is operated also apply.
7.
Causes of operating disturbances and their elimination
Disturbance
Possible causes
Elimination
Safety valve does not work - no
flow or slight flow
Protective cap of the inlet has not been
removed prior to installation of the
valve
Remove inlet protective cap.
Protective cap of the inlet flange has
not been removed prior to installation
of the valve
Remove the valve from the system and
clean inlet of the valve.
incorrect installation of the valve - the
flow of the medium is opposite with the
direction marked on the valve body
Install the valve correctly, in accordance
with the indications of manufacturer’s
instructions.
Too high set pressure, inadequate to
the requirements of secured
installation
If the required pressure is within the
scope of spring mounted on the valve- set
the safety valve to the required pressure,
if it is outside the scope of spring mounted
- replace the spring with the appropriate
one and set the required pressure. In
each case, act in compliance with
manufacturer’s instructions.
If the required pressure does not fall
within the scope of the safety valve type
mounted - replace the valve with the
appropriate type, with set pressure
adjusted to the required pressure.
backpressure not taken into
consideration (in case of conventional
valve, i.e. unbalanced)
I For stable superimposed backpressure -
set the differential pressure. For variable
superimposed backpressure - apply
bellows compensating backpressure
changes In each case, follow
manufacturer’s instructions and with
matters requiring clarification - consult
the manufacturer's technical advisor.
