Existing Fan Coil Problems in High Rise Apartments & Condos?

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There are many apartments and condos that have tremendous problems cooling a space. Many tenants/owners complain that during the peak cooling season they can’t cool large parts of their units.  There are two major reasons this happens in so many buildings, and it’s exasperated over the life cycle of operation.

Undersized initial design

  • Unit tonnage capability that’s very marginal for the application:
    • Lack of initial budget – creates an engineered design that was never going to work in some or all the units in the facility
    • Improper location of room thermostats – causes units to cycle off quickly before the entire space is cooled
    • Reduced air side performance of units – that’s based on ductwork that reduces unit air volume, which also reduces the BTUH output of the unit
    • Reduced air flow – drastically decreases the “air throw” and coverage within the space
    • Water side of the system in the building doesn’t produce the required GPM volume and/or the water temperature required to meet the air side BTUH load during peak cooling periods

Lack of scheduled maintenance

  • Fan Coil Units have no service factor for meeting their intended performance if units are not maintained properly.
    • Inlet and outlet grilles need to be cleaned at least every month and sometimes more depending on foreign material in the air.
    • Supply grilles, and especially double deflection type, must be kept wide open.  Many tenants tend to close these down because of local air draft.  However, closing the supply grilles reduces overall air flow and lowers BTUH due to increased resistance. 
    • Filters need to be changed at least four times a year, and sometimes more, because of foreign material in the air stream.  Owners often place electronic air cleaners in the duct or use higher efficiency filters. These additions may add extra resistance.  You might receive cleaner air, but the extra resistance from these additions can cause less air flow and less cooling BTUH into the space.
    • Coil cleaning is essential in a fan coil unit, especially when foreign materials can easily get into the unit and lodge in the core of the coil.  Many units do not have easy to clean coils, and most are a minimum of 12 to 14 fins per inch.  If a coil has a clean resistance of .3 inches, and it becomes dirt laden, this resistance can rise by 40% to 50% over time – drastically reducing system CFM and cooling.  Dirt in the core also acts as an insulator between the colder water inside the tubes and the warmer air running across the finned tube surface.  The heat transfer between the two steams can be reduced further by this insulating effect.

Can a unit replacement help alleviate these problems?

The answer is Yes.  Once everyone is aware of the problems, building in solutions to the new units is easy.  Some systems may need one or more of the following:  1) a stronger fan (better air distribution), 2) extra unit in the space (for severe hot spot issues), 3) more efficient coils (overcoming water side delivery problems), and 4) better location of thermostats (to prevent unit cycling on and off).  There are many additional control and valve issues that can be updated to achieve more efficient service and ease in monitoring air and water flow issues.

Southwest Coil exclusively represents USA Coil & Air in the Southwest Region and has been a leader in the replacement fan coil business for 4+ decades. We cut our teeth with coil replacement and moved on to the many problems associated with fan coil unit installations. Our line of horizontal and vertical fan coil units can fit in almost any existing application and most can be shipped on an expedited schedule. Our knowledgeable Sales Engineers are very familiar with the problems associated with fan coil products, and we will assist you with a seamless replacement process.

Contact the experts at Southwest Coil for all your coils needs!