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Troubleshooting Blower Problems

From excessive noise to under-performance: here are some basic things you should look in to when you’re having blower problems.

Here at S and A Engineering Services we like to assist our customers; new, old and yet-to-be, as best we can. That’s why we’ve compiled a list of common problems and how to remedy them.

IMPORTANT: work should only be carried out by an experienced engineer. The blower and driving motor should be electrically and mechanically isolated prior to inspection!

Advice Key:

❖            Consult manual or manufacturer for more information

■             Repair: in-house if capable or send to a professional blower repair company

□             On-site maintenance can be applied

Blower is unusually loud

CauseAdditional Notes
Possible Solution

Belts may not be aligned properly

□  Check and adjust if necessary

Bearing damage

■  Change bearings if you can (if no other fault is apparent) or send away for repair

There may be contact between the impellers / rotors with the end plates or cylinder
This can be caused by overheating, loss of timing (gear wear) or bearing wear

❖  When the machine is cool; check that the clearances are within recommended tolerances

□  Check the impeller lobes for wear or excessive clearance (which can affect performance)

□  Check for bearing and gear wear

■  Repair if damaged or badly worn

Foreign material or contamination in blower
Causes the impellers / rotors to contact each other

□  Remove contamination and clean the internals of the blower

■  Repair if damaged of badly worn

Particles in the gear wheels or bearings
Can cause noise, abnormal and accelerated wear and potentially gear or bearing failure and loss of timing

□  Check gear wheels and bearings for wear or contamination

■  Replace gears and bearings if contaminants are found in the lubrication, or they are found to be worn

Bent drive shaft

Usually caused by incorrectly setup drive, sudden shock-load or can be caused by external impact

■  Replace shaft or entire impeller as necessary

❖  Check loading and recommended pulley sizes

□  Amend drive as per loading recommendations when reinstalling the blower after repair

Loose blower, motor or pipework
can cause excessive vibrations and loss of performance

□  Check all bolts and tighten where loose

Blower is running too hot

CauseAdditional Notes
Possible Solution
Contaminated air filter
Restricts cooling air and can increase pressure

□  Clean or replace inlet filter with new


❖  Check operating data and make sure blower is running within parameters

□  Check for blockages in the line including non-functioning pressure relief valve / safety valve and non-return valve along with product build-up.

Ambient temperature too high

□  Ensure there is sufficient ventilation or cooling technology to cope with high temperatures

❖  Make sure the oil is suitable for use at high ambient temperatures

Restricted or clogged ventilation

□  Clean out the ventilation in the acoustic hood and in remote air feeds if applicable

Defective ventilation fan

□  Repair or replace with new

Lubrication level or type is incorrect
Check this for both oil and grease as per blower specification

□  Correct the oil and/or grease level

❖  Make sure this viscosity is correct for the number of running hours, ambient and discharge temperatures

Clearances are too large
Increased slippage can cause a backpressure in the line as the blower becomes inefficient

■  Send in for repair to replace damaged components.

Blower speed is too low
Reduces the amount of cooling air passing through the machine. Can also cause back-pressure

❖  Check blower is being run within parameters

□  Check drive belt tension and slippage: correct if necessary

Oil is present in the conveying medium

CauseAdditional Notes
Possible Solution
Oil level too high
Avoid over-filling.

□  Adjust oil level

□  Replace sight glasses if they are dirty (if present)

Worn seals or damaged labyrith sealing rings

■  Replace seals

Intake volume is too low (under-performance)

CauseAdditional Notes
Possible Solution
Starting strainer or inlet filter contaminated

□  Clean or replace with new

□  Remove starter strainer once it is no longer required

Leak in the process pipework

□  Inspect and seal piping

□  Check that relief valves are functioning correctly

Incorrect blower size or drive components used

Can happen for a few reasons, some being:

  • incorrect information provided when ordering
  • system change since blower installation

❖  Check performance data

□  Correct underperforming parts if within parameters (such as drive)

□  Replace blower with suitable alternative

Damaged or worn impeller / rotor or cylinder

■  Replace damaged components

Excessive power consumption

CauseAdditional Notes
Possible Solution
Operation is different from order specifications

Can happen for a few reasons, some being:

  • incorrect information provided when ordering
  • system change since blower installation

❖  Check performance data

□  Correct if within parameters

□  Replace blower with suitable alternative

Mechanical damage to the blower or motor

■  Repair if possible

□  Replace faulty items

Drop in motor voltage

❖  Refer to motor manual

□  Adjust the power

Pressure is too high
Can be caused by a blockage in the line; see also "Intake volume is too low (under-performance)"

Follow advice in "Intake volume is too low (under-performance)"and rectify any issues.

Belts are vibrating

CauseAdditional Notes
Possible Solution
Worn V-belts
Caused by general wear or incorrectly tensioned / aligned

□  Replace belts

□  Replace pulleys if worn or damaged

□  Correct alignment and tension.

Belts are incorrectly aligned.

□  Correct alignment and tension.

Drive pulleys have an estimated lift span of 6 years with continuous use; at which point, they should be checked and changed.

Blower runs in reverse direction after shutdown

CauseAdditional Notes
Possible Solution
Motor polarity reversed
Can occur when a motor is reinstalled or work has been carried out on the controls

□  Check motor direction and change accordingly

Non-return valve defective or leaking.

□  Replace valve

Blower will not turn over (seized)

CauseAdditional Notes
Possible Solution
see "Blower is running too hot" (above)

□  If the blower will turn over by hand after cooling: identify and correct all issues mentions in "blower is running too hot".

■  Send blower in for repair if internals appear badly damaged. The blower may need to be replaced.

Internal contamination
Insufficient filtration and incorrectly installed or faulty non-return valve can cause product to enter the blower

□  Check and replace filter if required

□  Check pipework and silencer integrity: replace if necessary

□  Check non-return valve is working correctly and is positioned in the pipework at the correct distance from the blower. Repair, replace or move if needed.

■  Repair if internals are worn

Drive shaft breakage

CauseAdditional Notes
Possible Solution
Excessive or overhanging load

❖  Check correct pulley dimensions

□  Change pulley configuration and drive if required

□  Correctly tension drive

■  Replace drive shaft or impeller / rotor

This is not an exhaustive list, so if you cannot see your problem listed here or you are unable to resolve your blower related issue, then please do seek further assistance.

S and A Engineering Services has been resolving blower issues for over 21 years and can provide over-the-phone assistance as well as on-site assistance and investigations. If you would like to speak to one of our team you can call them on (+44) 1204 326 387

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