Potential Problems With The Metering Tube; 21.3.1 Jammed Float; 21.3.2 Bent Top Float Stop; 21.3.3 Lack Of Magnetic Field - Techfluid SC250H Instruction Manual

21.3

Potential problems with the metering tube

21.3.1 Jammed float
In flowmeters up to DN80 a possible cause is that the float upper guide (4) or the lower one
(1) are bent due to a water hammer. To solve this, remove the circlip (6) which locks the top
float stop (7). Then remove the float stop (7). The float (2) can now be extracted. Align the
guide rods and manually check that the movement is good without rubbing.
For flowmeters DN100 or larger, the cause can be that the magnetic cylinder (10) is bent or
dirty. To solve this, extract the float (2) from the flowmeter by removing the screw (9) which
holds the float end (7). Then remove the float end. Extract the float (2) from the top of the
flowmeter and straighten or clean the magnetic cylinder (10).
Follow the above steps in reverse to reassemble the equipment.
The float may also become clogged by accumulation of metallic particles around it due to
the float magnetic field. In this case disassemble the float (2) following the above
instructions, clean it, and install a magnetic filter on the inlet of the meter, or just a normal
filter depending on the size and nature of the particles.
21.3.2 Bent top float stop
If the top float stop (7) is bent due to a water hammer, disassemble it following the
instructions of the section 21.1. If it is possible, straighten it and check its alignment.
Otherwise change it for a new one.
21.3.3 Lack of magnetic field
Disassemble the float (2) as indicated in section point 21.1. Check if the float has suffered
chemical aggression and if so the permanent magnet has been affected. If this is the case,
the float must be replaced and the flowmeter will have to be re-calibrated in Tecfluid S.A.
facilities.
21.3.4 Damaged calibrated orifice and / or float
Check that they do not show any impacts or scratches. Also check for any chemical attack.
If the float (2) is in bad condition it must be replaced. If the calibrated orifice (3) is damaged,
the metering tube and the float must be replaced. In both cases the flowmeter has to be re-
calibrated in Tecfluid S.A. facilities.
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