Mechanical

Experts in Ventilation

Mechanical
Problem	Possible Cause	Recommended Action
General Fan Noise	The fan could be running in stall.	Check the actual fan performance against the fan curve to determine where on the curve it is operating. If it is to the left of the peak pressure point the fan is generally in stall. If in stall see if the ductwork can be modified to eliminate high pressure loss sections. Low amps could indicate the fan is in stall. Reduce the pitch angle.

Bearing noise varying from a 'dry' rumble to a squeal	Improper greasing	Check the bearings are packed with the correct grade and amount of grease. If the bearings are of the sealed-for-life type replace them.

	The bearings may be loose on the shaft or bearing support	Tighten the adaptor sleeve or collar

	The bearings have not been properly tensioned	Re-tension as required

Rough lumpy sound	The bearings may have brinelled. Brinelling occurs when the fan is vibrated during transit or through ground vibrations when stored. This causes the bearing to vibrate at a single point and therefore indenting the bearing race. Problems with brinelling usually occur shortly after a fan is installed.	Replace the bearings. To Avoid brinelling the fan impeller should be rotated frequently, at least daily.

	Excessive belt tension	Check and adjust the belt tension

Shaft seal squeal	The seals may have dried out.	The seals may require lubrication or may be misaligned.

Air noise	Air noise can be generated from a number of sources such as grilles, bends, badly designed duct fittings, excessive duct velocities etc	Check the duct design is such it does not generate turbulence and therefore noise. An attenuator may be needed to resolve the problem.

Vibration	The impeller may be out of balance.	Site balancing may be practical but, if not, remove the impeller and balance.

	The shaft may be bent.	The shaft will have to be replaced.

	Impeller may be worn as a result of handling abrasive or corrosive materials	The impeller will have to be replaced

	Material such as dust or grease could be sticking to the fan blades.	Clean the impeller blades. This should be done on a regular basis if dust and/or grease are constantly present in the air being handled.

	The impeller may have been damaged by loose material in the duct system.	Depending on the level of damage the impeller may have to be replaced.

	Noise being transmitted through the building structure	Check vibration isolators have been fitted and, if fitted, check they are correctly positioned. Vibration isolators are fitted but not strong enough. If bottoming, adjust if possible or replace with more suitable mounts. Fit flexible connectors between the fan and ductwork.

TDE

The Multiflow TDE 500 to 710 range consist of fully cased, cylindrical models with circular mounting flanges at both ends and a wired terminal box.

The Mini Centrifugal Roof Fan series are the new type roof extract units available in 2 sizes and suitable for vertical and horizontal installation. The low noise external motor and high efficient backward bladed impeller meets the requirement of efficient ventilation in residential, commercial and light industrial applications.

Future 150

The Decor Series can be wall or ceiling mounted and is designed to exhaust stale and moist air from bathrooms, toilets, laundries etc. They are also suitable for ventilating all types of small or closed areas.

TD Silent

The Silent Series is a low profile mixed-flow in-line fan that produces low noise when in operation. It does this through a specifically designed perforated internal skin that directs sound waves produced inside the fan to a layer of sound absorbent material.

TD-Evo

NEW!! TD-EVO

The low-profile TD-EVO 250 and 315 in-line mixed-flow fans for circular ducts have a unique design where the support bracket allows the motor and impeller assembly to be fitted or removed without dismantling the adjacent ducting.