Choice Of Spring - FPZ VRL Serie Instrucciones Para El Uso

1. CHOICE OF SPRING

The valve is supplied with 2 different springs; each spring is to be used within a specific pressure-vacuum
operating range. For the VRL8 and VRL9 there is the possibility to use both springs working in parallel.
Referring to the SELECTION DIAGRAM, check that the valve is correctly sized and depending where the
operating point (area A, B,...H) is located, choose one or two springs according to SPRING SELECTION
CHART.
The valve is supplied with spring # Ι installed. If spring needs to be replaced or a supplementary spring is
needed to be added (for VRL8 / VRL9), proceed to point # 2 otherwise, adjust valve as per point #3.
2. INSTRUCTIONS FOR SPRING REPLACEMENT (OR MOUNTING ADITIONAL
SPRING FOR VRL8 / VRL9)
•
Remove the two plastic caps on valve.
•
Ensure stop-nut 923 is locked on the upper housing 106.
•
Unscrew screw 903 from nut 903.1.
•
Remove cover 107 from housing 106.
•
Unscrew spring guide disc 433 taking it out from shutter guide 434.
•
Remove spring 700 (only in case of replacement).
•
Install the appropriate spring into shutter 165.
•
Compress spring and screw spring guide disc 433 on shutter guide 434 for at least 20 full thread
terms.
•
Check that both ends of the spring are properly positioned within their seats.
•
Install the cover 107 on the housing 106 inserting:
- for VRL6: the sliding guide on the slot in spring guide disc 433.
- for VRL8 and VRL9: dowel pin 562 on the slot in spring guide disc 433.
•
Tighten screw 903 on nut 903.1.
3. VALVE SETTING
A) Setting-up at allowed vacuum level
•
Remove the two plastic caps on valve, if any.
•
Position valve on the suction by-pass and connect a vacuum gage as close as possible to the
exhauster inlet (Fig. 2).
•
Unscrew nut 923.
•
Relieve spring tension by backing off upper grub screw 904.1 with the fit key.
•
Turn on exhauster. Induce highest attainable vacuum by throttling air intake upstream relief valve
(normally reducing throttle to fully-closed).
•
Adjust upper grub screw 904.1 until maximum allowable vacuum level is reached.
•
Tighten nut 923 keeping blocked upper grub screw 904.1.
•
Open suction line.
Double-check vacuum gauge to ensure no additional losses are induced by pipes or filters
installed upstream relief valve.
B) Setting-up at allowed pressure level
•
Remove the two plastic caps on valve, if any.
•
Remove nut 923 from upper grub screw 904.1 and place it on to the lower grub screw 904.2. Do not
tighten.
•
Position valve on the discharge by-pass and connect a pressure gage as close as possible to the
blower outlet (Fig. 3).
•
Relieve spring tension by backing on lower grub screw 904.2 with the fit key.
•
Turn on blower. Induce highest attainable pressure by throttling air discharge downstream of the valve
(normally reducing throttle to fully-closed).
•
Unscrew lower grub screw 904.2 until maximum allowable pressure level is reached.
•
Tighten nut 923 keeping blocked lower grub screw 904.2.
•
Open discharge line.
Double-check pressure gauge to ensure no additional losses are induced by pipes or filters
installed downstream the valve
GB
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