Lennox Baltic BCK 020, Installation Operating & Maintenance Manual

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Page 32 - IOM / ROOFTOP BALTIC Series -
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VENTILATION BELT TENSION
BELT TENSION
On delivery, the drive belts are new and correctly tensioned.
After the first 50 operating hours check and adjust the
tension. 80% of the total elongation of belts is generally
produced during the first 15 hours of operation.
Before adjusting the tension, make sure that the pulleys are
correctly aligned.
To tension the belt, set the height of motor support plate by
moving the plate adjustment screws.
The recommended deflection is 16 mm per metre from
centre to centre.
Check that according to the diagram below (figure 30), the
following ratio remains the same.
P(mm) =
20
A(mm)
The belts should always be replaced when :
- the disk is set to maximum,
- the belt rubber is worn or the wire is visible.
Replacement belts must have the same rated size as the
ones they are replacing. If a transmission system has
several belts, they must all be from the same manufacturing
batch (compare serial numbers).
NOTE :
An under-tensioned belt will slip, heat and wear prematurely.
On the other hand, if a belt is over-tensioned, the pressure
on the bearings will cause them to over-heat and wear
prematurely. Incorrect alignment will also cause the belts to
wear prematurely.
Fig. 29
Fig. 30