Section 2
2.1 LIMIT SWITCH
The limit switch assembly of an actuator fitted direct on to a valve is set for the correct number
of turns before despatch and should not be disturbed.
Pedestal type actuators and actuators for fitting direct on to valves at site are despatched with
each switch bank set at 500.0 turns so that any mal-operation of the handwheel before the
actuator is coupled or fitted to the valve should not disturb the correct relationship of cams to
rollers. After coupling or fitting the actuator to the valve remove the limit switch cover and the
limit switch housing cover. Hand operate the valve to the full shut position, and observe that
the limit switch cams are in the correct re-set position, i.e. maximum cam throw 72° clockwise
of roller assembly. If for any reason the cam is in any other position, the correct position is easily
attained by withdrawing the hunting tooth spindle and rotating only the hunting tooth wheel
which registers multiples of 100 turns in a clockwise or anti-clockwise direction until the correct
cam position is obtained and the spindle re-engaged. This should be carried out without
disturbing the remaining digits. After noting the actual number of turns indicated on the 'close'
bank hand operate the valve in the open direction 0.3 turns of the limit switch counter
mechanism to the nearest 0.1 turn which will give a complete number in a straight line, in line
with the pinion and hunting tooth spindles. Withdraw the hunting tooth spindle of the 'close'
bank and re-set to 0000 turns (in line) and re-engage the spindle. Now set the 'intermediate'
and 'open' banks to the correct number of actuator output shaft turns from zero at which these
switches are required to trip.
Check by hand operation the tripping positions of the switch banks.
2.2 COMMISSIONING PEDESTAL UNITS
First ascertain that the valve is in the full shut position i.e. the stop is resting on the lower
shoulder of the valve pillars. Connect the valve and unit mechanically by the extension spindle
supplied taking care not to move the valve from the full shut position and also ensure that the
universal forks on the intermediate shaft are in line and not at 90° to each other.
2.3 COMMISSIONING DIRECT MOUNTED ACTUATORS
Valves which are to be fitted with direct mounted actuators at site are fitted with a circular
adaptor plate secured to the valve by the pillar nuts.
If a standard hand operated valve is to be motorised by means of a direct-mounted actuator,
remove the existing handwheel, gearing (when fitted) sleeve and bridge, leaving the valve
pillars and spindle only for application of the actuator. Remove the circular adaptor plate from
the base of the actuator and fit this item on the valve pillar ends and secure by means of the
existing pillar nuts. Do not remove any covers at this stage but engage manual operation in
preparation for fitting to the valve.
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