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

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.

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

Ref	Type	Task/Activity/Check
W-1	Inspect	Observe and review the unit for any changes in operating conditions
W-2	Inspect	Check for any unusual noises
W-3	Inspect	Check 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

Ref	Type	Task/Activity/Check
M-1	Change/Clean	Filters – 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-2	Inspect/Clean	Condensate Drain Pan – Visually inspect and if dirty or debris accumulated fully clean
M-3	Inspect/Clean	Wet coils – Visually inspect and if dirty or debris accumulated clean
M-4	Inspect/Clean	Strainer – 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

Ref	Type	Task/Activity/Check
6-1	Inspect	Fan – 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
6-2	Inspect	Motor – check the bracket for the motor and that the torque is still correct
6-3	Inspect/Clean	Wet coils – complete a more detailed visual inspection and if dirty or debris accumulated fully deep clean
6-4	Test	Control valves – ensure that the FCU control valve is operating as per design, not damaged and the actuator is still fixed properly
6-5	Inspect	Fresh Air Ducting– Visually inspect to ensure free and clear and the connection to the FCU plenum is in good condition
6-6	Inspect	Insulation to Fresh Air Ducting – Visually inspect to ensure has no damage, torn and that the vapor barrier is unaffected.
6-7	Inspect	Recirculating Air Ducting – Visually inspect to ensure free and clear and the connection to the FCU plenum and grille is in good condition
6-8	Inspect	Insulation to Recirculating Air Ducting – Visually inspect to ensure has no damage, torn and that the vapor barrier is unaffected.
6-9	Inspect	Supply Air Ducting – Visually inspect to ensure free and clear and the connection to the FCU plenum and grilles are in good condition
6-10	Inspect	Insulation to Supply Air Ducting – Visually inspect to ensure has no damage, torn and that the vapor barrier is unaffected.
6-11	Inspect/Clean	Air Vent – Inspect the air vent to ensure not blocked and clean/in good condition
6-11	Test	Condensate – 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
6-13	Test	Electrical – 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

Ref	Type	Task/Activity/Check
12-1	Inspect	General – Check all screws and bolts on the unit are tight and secure
12-2	Inspect/Clean	Fan – clean the fan, blades, and impeller, remove any rust from the shaft and recoat where necessary
12-3	Adjust	Fan – Adjust the fan if rubbing
12-4	Inspect/Adjust	Electrical – check the tightness of connections
12-5	Test	Fresh Air – Measure airflow rate to ensure in line with design requirements
12-6	Test	Recirculation air – Measure airflow rate to ensure in line with design requirements
12-7	Test	Supply air – Measure airflow rate to ensure in line with design requirements
12-8	Inspect	Volume Control Dampers [VCD] – Inspect the volume control dampers on fresh air, recirculating air, and supply air to ensure in good condition
12-9	Test	Fire 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.
12-10	Test	Chilled Water – Measure water flow rate to the coil to ensure in line with the design requirements
12-11	Test	Heating Water – Measure water flow rate to the coil to ensure in line with the design requirements
12-12	Inspect	Pipework Connections – Inspect the flexible hoses and connects to ensure are in good condition
12-13	Inspect	System – 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

Ref	Type	Task/Activity/Check
4-1	Test	Fire 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 1	Understand if need to remove any of the ceilings from around the unit to gain access
Step 2	Make sure are wearing the correct personal protective equipment
Step 3	Ensure have the correct access equipment
Step 4	Ensure have the correct tools
Step 5	Ensure have the correct protection for surrounding areas, so as not damaged by the cleaning
Step 6	Isolate the FCU by disconnecting and locking it off
Step 7	Open the FCU to gain access to the coil, remove the supply air plenum if required
Step 8	Using a soft brush or a coil cleaning brush, remove any loose debris from both sides of the coil
Step 9	On 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 10	Using a spray/pump [the best is a garden type spray pump]
Step 11	Mix 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 12	Keep the nozzle of the sprayer at least 6″ from the coil, perpendicular, and a spray angle of about 15 degrees.
Step 13	Spray the side of the coil where the air leaves it first.
Step 14	Then move the barrier as noted in step 9 to the other side
Step 15	Spray the side of the coil where the air enters.
Step 16	Remove 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 17	Rinse the coil and drain pan with clean water and repeat the cleaning process as needed until the coil is clean
Step 18	Once the coil is deemed clean remove any protection barriers
Step 19	Using a coil fin repair tool, straighten any aluminum fins that may be damaged or bent
Step 20	Inspect the condensate drain to ensure it is not blocked
Step 21	Allow the coil to dry before putting back into operation
Step 22	Ensure all panels, access panels, electrical panels, etc are reinstalled and closed
Step 23	Restart 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 1	Understand if need to remove any of the ceilings from around the unit to gain access
Step 2	Make sure are wearing the correct personal protective equipment
Step 3	Ensure have the correct access equipment
Step 4	Ensure have the correct tools
Step 5	Ensure have the correct protection for surrounding areas, so as not damaged by the cleaning
Step 6	Isolate the FCU by disconnecting and locking it off
Step 7	Remove any standing water in the drip pan, with a wet vac, rags/clothes, etc
Step 8	Remove any debris from the drain pan
Step 9	Using a clean cloth clean the surface of the drain pan
Step 10	Remove any stubborn solid matter with a scraper, be careful not to damage the drain pan
Step 11	Using a vacuum cleaner remove any dust
Step 12	If needed, use mild bleach to clean any areas and wipe down
Step 13	Rinse 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 1	Understand if need to remove any of the ceilings from around the unit to gain access
Step 2	Make sure are wearing the correct personal protective equipment
Step 3	Ensure have the correct access equipment
Step 4	Ensure have the correct tools
Step 5	Ensure have the correct protection for surrounding areas, so as not damaged by the cleaning
Step 6	Isolate the FCU by disconnecting and locking it off
Step 7	Open the FCU to gain access to the fan and motor
Step 8	Remove loose debris from the fan compartment and around the fan/motor by using a vacuum cleaner
Step 9	Any 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 10	Wipe down the interior of the fan housing removing any small deposits
Step 11	Ensure areas are dry
Step 12	Install 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 1	Understand if need to remove any of the ceilings from around the unit to gain access
Step 2	Make sure are wearing the correct personal protective equipment
Step 3	Ensure have the correct access equipment
Step 4	Ensure have the correct tools
Step 5	Ensure have the correct protection for surrounding areas, so as not damaged by the works
Step 6	Understand if the fan motor is vibrating excessively
Step 7	Isolate the FCU by disconnecting and locking it off
Step 8	Open the FCU to gain access to the fan and motor
Step 9	Check and adjust the fan wheel screws, ensuring they are in line with the torque requirements of the manufacturers
Step 10	If 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.

Issue	Possible Cause	Action
FCU Internals are wet	Drain pan/condensate pan leaks	Repair
–	Condensation forming in unit	Insulate
–	Airflow across the coil too high	Reduce airflow
The motor does not start/spin	Switched off	Check the status of the switch
–	Fan blades are blocked/obstructed	Check fan blades for any obstructions
–	Fuse blown	Check fuse/replace
–	Electrical overload active	Reset overload protection
–	Cabling incorrect	Review manufacturers wiring requirements/drawings with actual site installation
–	Electrical supply incorrect	Speak to an electrician to check current and voltages
Motor stops unexpectedly	Incorrect/low voltage	Check electrical inputs
Fan/unit vibrates	Fan not aligned correctly	Check fan alignment and realign if needed [manufacturer[
–	Transportation bolts not removed	Remove transport bolts
Unit/motor is noisy	Fixings/brackets lose	Check tightness/torque and tighten where required
–	Rigid connection to ancillary ductwork	Replace rigid connections with flexible ones
–	Fan hitting cover	Remove obstruction
The motor does not meet the required speed	Low voltage at motor terminal	Correct electrical voltage
–	Wiring sizes not large enough to motor	Check to wire/rewire if needed
The motor is very hot/overheats	The motor is overloaded/too small	Check the motor size is the same as the plate information on the unit.   Reduce load on motor   Replace motor
–	Ventilation to the motor is obstructed	Check and clean/remove
Cooling capacity is too low	Airflow not enough	Check air flow rate
–	Coil water flow is not enough	Check water flow rate
–	Water temperatures incorrect	Check the water flow and return temperatures
–	Pipework connections incorrect/wiring way around	Check flow and return connections
–	Coil is blocked	Check cleanliness of coil and clean/remove blockage if needed
Drain pan/condensate pan overflowing	Condensate pipework blocked	Rod and clean pipework
–	Drain pan not installed to correct level	Check level and make sure inline with the manufacturer’s requirements
–	Pipework trap not correct	Check trap design
Standing water in drain pan/condensate pan	Condensate pipework blocked	Rod and clean pipework
–	Drain pan not installed to correct level	Check level and make sure inline with the manufacturer’s requirements
–	Pipework trap not correct	Check trap design

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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.

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