Thread forming screws must have locking compound applied when being reused. Those fixings that have no
locking devices fitted and are not painted over, should be checked at 95% of their original setting to ensure no
unnecessary disturbance of the fixing. See Figures 6 and 7 for torque setting details. If in doubt about the torque
of a particular fixing contact Fläkt Woods Limited for advice.
6.2 LUBRICATION
In addition to routine maintenance motor bearings will in the longer term require attention. If the motor bearings
are greased through extended lubricators, a quality of grease should be periodically applied in accordance with
the information on the fan or motor nameplate and/or instructions provided. A compatible grease type must be
used and it is essential that every trace of water and dirt is removed from around the grease points and that a
clean grease gun is used. Only low pressure should be needed to inject the specified quantity of grease. If a high
pressure is required, the cause should be investigated. Grease points are generally located in the region of the
duct terminal box.
For motors that require re-lubrication, a separate instruction is issued with each fan/motor configuration. This
details both the period between lubrication and the type of grease to be used. If you require any further details
please contact Fläkt Woods Limited direct.
6.3 INFREQUENT USE
If the fan assembly is to be used less frequently than once a month, or for emergency-use only, the following
additional maintenance procedures should be carried out, and a record kept:
- The resistance of the motor windings to earth, should be measured (at 500V d.c) each month. If the
reading is less than ten megohms, the motor should be dried in a warm airflow (typically
40°C) and re-checked before running the motor.
- The fan should be operated between 15 and 30 minutes each month ensure that correct lubricant
conditions are maintained within the bearings.
- The ‘emergency-use’ system should be run continuously for a minimum of fifteen minutes each month,
the test should ensure that the emergency use control system overrides all other controls and
switches (see Paragraph 5.5).
- If an anti-condensation heater is fitted, check each month that it is automatically switched on
(drawing current) when the motor is switched to off.
7. OVERHAUL / EXTENDED MAINTENANCE
Advice on motor overhaul procedures, bearing/seal replacement, motor replacement, motor rewinding, spare
parts, condition monitoring, vibration analysis, refurbishment, etc. is available from Fläkt Woods Limited service
centre in Colchester.
For emergency use fans it is recommended that the motor shaft seals and bearings are replaced after 20,000
hours or 5 years of normal operation which ever comes sooner, and that the motor is rewound to its original
specification after 40,000 hours of normal operation to ensure that adequate insulation life is available should the
fan be required for emergency operation.
NOTE!
With High Temperature fans, only an authorised company may undertake the maintenance. Failure to do
so may invalidate any warranty and CE Certification. The motor manufacturer’s specification sheets are
available through Fläkt Woods Limited.
After overhaul/extended maintenance the fan assembly must be correctly installed back into its original position
in accordance Paragraphs 1, 2, 3 and 4 of this document.
For advice on “switching on” after maintenance, please refer to paragraph 5.7.
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