BENSON MH300, User Instructions

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(f) Fit the eccentric collar and engage the
cams.
(g) Tighten initially by rotating, and then by
tapping in the direction of the fan rotation.
(h) Replace fasteners and secure.
(i) Turn by hand to ensure free fan rotation.
Pulleys
Check pulleys for alignment using a straight
edge, if necessary reposition either or both of
the pulleys and the fan motor.
Check for excessive wear within the root and
sides of the grooves, and check for any other
signs of wear or damage, if necessary replace
the pulley as follows.
(a) Release tension on belts and remove.
(b) Release the taper locks by slackening the
securing screws by several complete turns.
(c) Fully remove one screw from the taper lock,
and having oiled it, insert into the threaded
jacking point.
(d) Tighten screw until the taperlock is free.
(e) Remove taperlock and pulley.
(f) Fit taperlock in new pulley, and provisionally
position on the shaft.
(g) Remove the screw from the jacking point,
and tighten both screws in their clamping
points until the pulley can just be moved on the
shaft by hand.
(h) Align pulleys using a straight edge, and by
gradual alternate tightening of the screws
clamp in position.
(i) Refit belts and check for the correct amount
of tension.
Fan Belts
Check belts for signs of wear.
Frayed or split belts must be replaced using
belts with a common batch code.
Belt tension must be checked, and if on multi-
belt units it is found that one belt contains
more slack than its accompanying belts, then
all the belts on the unit must be replaced,
again using a common batch code.
Replacement and tensioning is carried out as
follows.
Note
The maximum displacement at the mid point of
the top edge of the belt must not be greater
than 16mm per metre of span, when a force of
3kg is applied in a plane perpendicular to the
belt.
(a) Loosen fan motor securing bolts on
chassis.
(b) Loosen fan motor slide adjustment bolt.
(c) Slide fan towards fan to slacken belts.
(d) Replace belts, pull fan motor away from fan
until belts are tight.
(e) Tighten adjustment bolt to hold motor.
(f) Tighten fan securing bolts ensuring that the
fan is square and the pulleys aligned.
(g) Check belt tension, making final
adjustments as necessary.
(h) Tighten and clamp fasteners to hold fan
motor in position.
Heat Exchanger
The heat exchanger requires a visual
inspection at least once per year, this should
be accompanied by cleaning. It is
recommended that a flue brush and vacuum
cleaner be used to facilitate this.
Access to the heat exchanger is gained
through the removal of the Front panel and
heat shield.
Servicing and cleaning should be performed as
follows.
(a) Remove brass nuts and cover from heat
exchanger end assembly to expose heat
exchanger tubes.
(b) Remove any accumulated deposits from
the tubes by pushing through the full length
with a flue brush.
(c) The flue brush should be withdrawn so as
to pull any deposits back into the bottom of the
flue box where they can then be removed by
using a vacuum cleaner.
(d) Particular attention should be paid to the