Inspection And Service; Troubleshooting - ITT Flygt 4901 Instalación, Servicio Y Mantenimiento

InsPeCtIon AnD seRVICe

oil
The flush valve 4901 is delivered with a rapeseed oil
which is "environmentally friendly". The freezing point
of this oil is –30°C. An alternative to this oil is to use a
mineral oil in accordance with ISO VG 32.
note
An oil with a higher viscosity gives a longer flushing
period and an oil with a lower viscosity gives a shorter
flushing period compared with the oil supplied.

tRoUBLesHootInG

The most frequent problem is that the inlet to the flush
valve is clogged by a hard particle, too large for the
valve throughlet.
note
The maximum recommended flushing time is 50
seconds.
If the flush valve is working at a too low pressure, the
closing time will be extremely long regardless of the
regulating valve setting "1". Finally the valve does not
close at all.
Please note the limits for each execution.
Providing the flush valve is operating within the limits,
but does not close within a reasonable time, perform
the following test:
18 Installation, Care and Maintenance Flygt 4901, Flush Valve
All manuals and user guides at all-guides.com
Inspection
note. If the flush valve is taken out of the liquid for
more than four days, the ball and the inner wall of
the valve body should be greased.
The ball must be replaced if the diameter is less than
59 mm.
Major overhaul
Under normal operating conditions, the flush valve
should be subjected to a major overhaul in a service
workshop every three years.
– Replace the inner membrane.
– Grease the ball + the inner wall of the valve body*.
– Dismantle the outlet bend.
– Regulating valve setting "1".
The flush valve should now close within max. 50
seconds if the reduced duty head is within the
limits.
note
All other solutions, such as "own" outlet bends or
applications may destroy the required underpressure
and may lead to a non-closing flush valve.
* For the pumps 3085 and 3102, please note the
possibility of using the polyurethane ball instead of
the steel ball.
(en)