FAN COIL UNIT | Week, Month, 6 months, Year & 4 Year Inspections Listed

December 6, 2022 |

Fan coil unit maintenance inspections should be completed at the following intervals – Weekly | Monthly | 6 Months | 1 Year and 4 Years, here we detail what should be inspected and documented…

The below list, there are 8 main reasons for maintaining a fan coil unit, and not having a detailed maintenance programme can have some significant consequences:

  • Higher failure rates of the equipment and its components, increasing overall costs and maintenance/repair requirements.
  • Higher running costs, due to the blower motor having to work harder to blow the air through unmaintained filters and coils.
  • Coils unable to operate to their peak efficiency, operating conditions and performance characteristics.
  • Additional complaints from occupants, because comfort levels are affected dur to the coils, controls and valves not working as designed.
  • Smells and general internal air quality problems, from dirty filters, coils and drain pans/drip trays.
  • Damage to existing installations, for example ceilings [horizontal units] and walls [vertical units] becoming contaminated from airborne dirt particles and dirty air, this is usually seen by dirty streaks.
  • Worse case.. fire risk, due to build up of potentially combustible materials.
  • General operation, trouble shooting issues early will help maintain an efficient system

Understanding the above and why it is important to complete this work the next thing is, how do you maintain a fan coil unit?.

In the below article we will go through a typical maintenance regime for the piece of equipment, most people will only concentrate on the actual unit but there are other items that should be checked, inspected, and maintained, as will see.

Fan Coil Unit Maintenance Checklist [MS Word]

To make life easier, we have created and made available this Inspection Checklist in [MS Word] for easy use on your projects.

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Who will usually manage and complete the maintenance:

If the building construction process is still ongoing or it is still within the defects liability period then the responsibility for the maintenance could be the general/main contractor. Best check with the client/owner of the building.

If the building is outside of the defects liability period then the maintenance of the unit will usually be completed by the building facilities manager/operator.

They will either have their own in-house team to complete the works or will sublet to a facilities maintenance/building services contractor.

22 components of a fan coil unit system

An FCU system will be made up of the following components that should be included in the fan coil maintenance programme:

  • Fan Coil Unit
  • Filter
  • Blower/Fan motor
  • Aluminum cooling coil
  • Heat exchanger [wet or electric]
  • Intake plenum
  • Supply air plenum
  • Pipework
  • Control valve including actuator
  • Water balancing valve
  • Air vent
  • Strainer
  • Flexible connections
  • Condensate drain pan
  • Condensate pipework
  • Fresh air ductwork
  • Recirculating ductwork
  • Recirculating grille
  • Supply air ductwork
  • Supply air grille
  • Volume control dampers
  • Fire dampers [sometimes]
If you would like to understand more about fan coil units check out our article 'Fan Coil Units | What, Where & How', for more information.

Standard routine maintenance schedule

How often should a fan coil unit be serviced and maintained?. A decent facilities company will have a detailed maintenance programme for all the equipment that is under their management and control.

The routine and timings of the inspections will vary from equipment to equipment, for the FCU it can be broken into the following:

  • Weekly Inspections
  • Monthly Inspections
  • 6 monthly inspections
  • Yearly inspections
  • 4 Yearly inspections

As each time frame increases so do the requirements. For example, the weekly inspection compared to the yearly inspections will be completely different in how long it will take and what will be inspected/checked.

If we take standard manufacturers requirements the units will need to be maintained as per the below table:

Weekly Inspection Checklist:

Ensure unit is running

RefTypeTask/Activity/Check
W-1InspectObserve and review the unit for any changes in operating conditions
W-2Inspect Check for any unusual noises
W-3InspectCheck temperature setting to ensure as per design/operational needs

Monthly Inspection Checklist:

Ensure unit is isolated, switched off & locked off

Complete the following, adding the weekly tasks to the schedule

RefTypeTask/Activity/Check
M-1Change/CleanFilters – Visually inspect and if clogged or dirty clean or replace If they are the permanent/washable type filter can be cleaned If not then replace
M-2Inspect/CleanCondensate Drain Pan – Visually inspect and if dirty or debris accumulated fully clean
M-3Inspect/CleanWet coils – Visually inspect and if dirty or debris accumulated clean
M-4Inspect/CleanStrainer – Remove strainer mesh inspect and clean

6 Months Inspection Checklist:

Ensure unit is isolated, switched off & locked off

Complete the following, adding the monthly and weekly tasks to the schedule

RefTypeTask/Activity/Check
6-1InspectFan – manually rotate the fan to check for any obstructions, the access panel to the FCU will need to be removed to allow full access and visibility to the fan housing
6-2InspectMotor – check the bracket for the motor and that the torque is still correct
6-3Inspect/CleanWet coils – complete a more detailed visual inspection and if dirty or debris accumulated fully deep clean
6-4TestControl valves – ensure that the FCU control valve is operating as per design, not damaged and the actuator is still fixed properly
6-5InspectFresh Air Ducting– Visually inspect to ensure free and clear and the connection to the FCU plenum is in good condition
6-6InspectInsulation to Fresh Air Ducting – Visually inspect to ensure has no damage, torn and that the vapor barrier is unaffected.
6-7InspectRecirculating Air Ducting – Visually inspect to ensure free and clear and the connection to the FCU plenum and grille is in good condition
6-8InspectInsulation to Recirculating Air Ducting – Visually inspect to ensure has no damage, torn and that the vapor barrier is unaffected.
6-9InspectSupply Air Ducting – Visually inspect to ensure free and clear and the connection to the FCU plenum and grilles are in good condition
6-10InspectInsulation to Supply Air Ducting – Visually inspect to ensure has no damage, torn and that the vapor barrier is unaffected.
6-11Inspect/CleanAir Vent – Inspect the air vent to ensure not blocked and clean/in good condition
6-11TestCondensate – Test that the condensate pan and pipework still operates as design by pouring 2 liters of water into it and ensuring it flows out to discharge
6-13TestElectrical – check the operation of emergency stop

Yearly Inspection Checklist:

Ensure unit is isolated, switched off & locked off

Complete the following, adding the 6 monthly, monthly and weekly tasks to the schedule

RefTypeTask/Activity/Check
12-1InspectGeneral – Check all screws and bolts on the unit are tight and secure
12-2Inspect/CleanFan – clean the fan, blades, and impeller, remove any rust from the shaft and recoat where necessary
12-3AdjustFan – Adjust the fan if rubbing
12-4Inspect/AdjustElectrical – check the tightness of connections
12-5TestFresh Air – Measure airflow rate to ensure in line with design requirements
12-6TestRecirculation air – Measure airflow rate to ensure in line with design requirements
12-7TestSupply air – Measure airflow rate to ensure in line with design requirements
12-8InspectVolume Control Dampers [VCD] – Inspect the volume control dampers on fresh air, recirculating air, and supply air to ensure in good condition
12-9TestFire Dampers – Fresh air, recirculating air & supply air, if 1 year after completion of the installation, test the fire dampers to ensure operates as per design. It will be required to be tested every 4 years after that.
12-10TestChilled Water – Measure water flow rate to the coil to ensure in line with the design requirements
12-11TestHeating Water – Measure water flow rate to the coil to ensure in line with the design requirements
12-12InspectPipework Connections – Inspect the flexible hoses and connects to ensure are in good condition
 12-13InspectSystem – check over the system for any evidence of corrosion and repair if any found
If you want ot learn more about fire dampers and testing see our article 'Easy Guide | Fire Damper Testing', for more information

4 Yearly Inspection Checklist:

Ensure unit is isolated, switched off & locked off

Complete the following, adding the 6 monthly, monthly and weekly tasks to the schedule

RefTypeTask/Activity/Check
4-1TestFire Dampers – Fresh air, recirculating air & supply air, test the fire dampers to ensure operates as per design.

Tips and Steps to Complete Tasks

The below we run through some steps to complete the maintenance and cleaning of the following:

  • Filters
  • Hydrostatic Coil
  • Drain Pan
  • Fans &
  • Fan Motors

After we cover some troubleshooting that can be completed if note any issues.

Filter Maintenance

Filters are installed to stop the accumulation of grime, dirt, and debris on the fan blades and coils that have been installed.

As noted in the above tables, they should generally be inspected every month and will generally be expected to be changed a minimum of two times throughout the year. It could be more depending on the environment the unit is installed into, the dirtier the recirculating/fresh air the more changes will be required.

Air filters are affected from built-up dirt, so can be one of the main causes of low airflow and underperforming unit.

There are usually three [3] types of filters we will find installed in a fan coil unit:

  • Disposable
  • Washable [fabric]
  • Washable [metal]

Hopefully by now, with the environment, the most common is the washable metal type.

To replace the filter they will usually just slide into a filter enclosure, located at the back of the unit.

Make sure that the arrows marked on the filter are in the correct direction – usually towards the fan.

Cooling and Heating Coil Maintenance

Coils, like the filters above, can have a large impact on the performance of the equipment. If the coil is dirty and blocked, it will not perform very well, create additional resistance, increase running costs and create unpleasant smells.

After inspection and if it is determined that the coil needs cleaning then this must be completed.

23 Step Coil Cleaning Process.

There are a couple of ways to do this, one of them is detailed in steps below:

Step 1Understand if need to remove any of the ceilings from around the unit to gain access
Step 2Make sure are wearing the correct personal protective equipment
Step 3Ensure have the correct access equipment
Step 4Ensure have the correct tools
Step 5Ensure have the correct protection for surrounding areas, so as not damaged by the cleaning
Step 6Isolate the FCU by disconnecting and locking it off
Step 7Open the FCU to gain access to the coil, remove the supply air plenum if required
Step 8Using a soft brush or a coil cleaning brush, remove any loose debris from both sides of the coil
Step 9On the air entering side of the coil, place a barrier to stop any water penetrating and wetting or damaging other services and systems. A plastic sheet taped around the flange should be ok.
Step 10Using a spray/pump [the best is a garden type spray pump]
Step 11Mix a good quality coil cleaning solution with water into the spray bottle [follow manufacturers instructions + the FCU coil manufacturers instructions to ensure correct mixing ratio]
Step 12Keep the nozzle of the sprayer at least 6″ from the coil, perpendicular, and a spray angle of about 15 degrees.
Step 13Spray the side of the coil where the air leaves it first.
Step 14Then move the barrier as noted in step 9 to the other side
Step 15Spray the side of the coil where the air enters.
Step 16Remove any large pieces of debris from the drain pan by hand [do not allow to flow down the drain as could cause a blockage] 
Step 17Rinse the coil and drain pan with clean water and repeat the cleaning process as needed until the coil is clean
Step 18Once the coil is deemed clean remove any protection barriers
Step 19Using a coil fin repair tool, straighten any aluminum fins that may be damaged or bent
Step 20Inspect the condensate drain to ensure it is not blocked
Step 21Allow the coil to dry before putting back into operation
Step 22Ensure all panels, access panels, electrical panels, etc are reinstalled and closed
Step 23Restart the unit
 Done…

13 Step Drain Pan Cleaning Process 

Pretty much overlooked, cleaning the drain/condensate pan is an important task especially if there is any standing water or if the pan is overflowing, here are the steps that can be taken:

Step 1Understand if need to remove any of the ceilings from around the unit to gain access
Step 2Make sure are wearing the correct personal protective equipment
Step 3Ensure have the correct access equipment
Step 4Ensure have the correct tools
Step 5Ensure have the correct protection for surrounding areas, so as not damaged by the cleaning
Step 6Isolate the FCU by disconnecting and locking it off
Step 7Remove any standing water in the drip pan, with a wet vac, rags/clothes, etc
Step 8Remove any debris from the drain pan
Step 9Using a clean cloth clean the surface of the drain pan
Step 10Remove any stubborn solid matter with a scraper, be careful not to damage the drain pan
Step 11Using a vacuum cleaner remove any dust
Step 12If needed, use mild bleach to clean any areas and wipe down
Step 13Rinse the drain pan quickly if using chemicals to clean and remove with a wet vac or rags/cloths.
 Put back into service & clean up…

12 Steps for Fan Maintenance and Cleaning

To ensure that the fans are maintained and clean, the following steps can be taken:

Step 1Understand if need to remove any of the ceilings from around the unit to gain access
Step 2Make sure are wearing the correct personal protective equipment
Step 3Ensure have the correct access equipment
Step 4Ensure have the correct tools
Step 5Ensure have the correct protection for surrounding areas, so as not damaged by the cleaning
Step 6Isolate the FCU by disconnecting and locking it off
Step 7Open the FCU to gain access to the fan and motor
Step 8Remove loose debris from the fan compartment and around the fan/motor by using a vacuum cleaner
Step 9Any stubborn solid matter that is left behind, on the fan blades, spray some water on to loosen and remove manually. Be careful of any electrical components and don’t get water on them or near them.
Step 10Wipe down the interior of the fan housing removing any small deposits
Step 11Ensure areas are dry
Step 12Install access covers, ready to start the fan.

10 Steps for Fan Motor Maintenance

To ensure that the motors are maintained and clean, the following steps can be taken:

Step 1Understand if need to remove any of the ceilings from around the unit to gain access
Step 2Make sure are wearing the correct personal protective equipment
Step 3Ensure have the correct access equipment
Step 4Ensure have the correct tools
Step 5Ensure have the correct protection for surrounding areas, so as not damaged by the works
Step 6Understand if the fan motor is vibrating excessively
Step 7Isolate the FCU by disconnecting and locking it off
Step 8Open the FCU to gain access to the fan and motor
Step 9Check and adjust the fan wheel screws, ensuring they are in line with the torque requirements of the manufacturers
Step 10If a motor is needing to be removed and replaced, refer to the manufacturer’s instructions as the process is quite individual to each type.

How do you troubleshoot a fan coil unit?

The below provides a common troubleshooting guide that can be referenced but the best information is directly reading the manufacturer’s literature.

IssuePossible CauseAction
FCU Internals are wetDrain pan/condensate pan leaksRepair
Condensation forming in unitInsulate
Airflow across the coil too highReduce airflow
   
The motor does not start/spinSwitched offCheck the status of the switch
Fan blades are blocked/obstructedCheck fan blades for any obstructions
Fuse blownCheck fuse/replace
Electrical overload activeReset overload protection
Cabling incorrectReview manufacturers wiring requirements/drawings with actual site installation
Electrical supply incorrectSpeak to an electrician to check current and voltages
   
Motor stops unexpectedly Incorrect/low voltageCheck electrical inputs
  
Fan/unit vibratesFan not aligned correctlyCheck fan alignment and realign if needed [manufacturer[
Transportation bolts not removedRemove transport bolts
   
Unit/motor is noisyFixings/brackets loseCheck tightness/torque and tighten where required
Rigid connection to ancillary ductworkReplace rigid connections with flexible ones
Fan hitting coverRemove obstruction
   
The motor does not meet the required speedLow voltage at motor terminalCorrect electrical voltage
Wiring sizes not large enough to motorCheck to wire/rewire if needed
   
The motor is very hot/overheatsThe motor is overloaded/too smallCheck the motor size is the same as the plate information on the unit.   Reduce load on motor   Replace motor
Ventilation to the motor is obstructedCheck and clean/remove
   
Cooling capacity is too lowAirflow not enoughCheck air flow rate
Coil water flow is not enoughCheck water flow rate
Water temperatures incorrectCheck the water flow and return temperatures
Pipework connections incorrect/wiring way aroundCheck flow and return connections
Coil is blockedCheck cleanliness of coil and clean/remove blockage if needed
   
Drain pan/condensate pan overflowingCondensate pipework blockedRod and clean pipework
Drain pan not installed to correct levelCheck level and make sure inline with the manufacturer’s requirements
Pipework trap not correctCheck trap design 
   
Standing water in drain pan/condensate panCondensate pipework blockedRod and clean pipework
Drain pan not installed to correct levelCheck level and make sure inline with the manufacturer’s requirements
Pipework trap not correctCheck trap design 

FCU Inspection and Maintenance Checklist [pdf]

To make life easier, we have created and made available this Inspection Checklist in [MS Word] for easy use on your projects.

047-Fan-Coil-Inspection-Schedule-PDF


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