Thursday, 08 October 2015 14:43

Reasons Coils Fail Prematurely

Evaporator or condensing coils are an imperative part of your overall HVAC system operation.  They provide the system an avenue to rid the building of heat and thus help to cool the the space.  Coils that are not functioning well directly impact the efficiency of the HVAC system and increase operating costs and also reduce the system's life expectancy.  A regular inspection of the coils should be a regular part of the systems maintance plan to keep your organizations HVAC system in peak operating condition.    
Here are some of the most common reasons coils can fail before their time:DIRTY CLEAN SLIDE20150214-15769-fht7zw 960x435
  • Plugged Coils - If filters are not changed or your coil cleaned in a timely manner, your coil will actually act as a filter.  When dirt builds up on the coil, it will prevent heat transfer and can cause a 20% to 40% drop in performance.  Dirt adds to the coil resistance and will absolutely cause your coil to fail prematurely.
  • Vibration - When your coil is installed near a moving piece of equipment, vibration can occur and cause leaks.  The area where these leaks occur is very important and will clue you in to if the problem is vibration.  If they are near the tube sheet and look like they are slicing through the tube, the coils should be isloated from the rest of the sysytem to prevent the vibration from causing damage.
  • Corrosive Environment - This applies to both the air in the environment and inside the tubes.  For instance, if there is something in the air that is corrosive, it will eat away at the copper tubes whether you have 0.020" wall or 0.049" wall.  This is very common in areas where they may be salt in the air.  To keep costs down from going to a stainless steel or cupro-nickel coil, we usually suggest coating the coil.  Coatings are almost always within the budget and only add about a week to lead time.  Steam condensate and untreated water can cause corrosion within the tubes as well.  If you have a steam coil that has failed before the one year warranty, there is a great chance corrosive agents are inthe steam and it's eating away at the copper tubes.
  • Freezing - Most people think that when a coild freezes, the water or condensate laying on the coil freezes into ice and it expands causing the tubes to bulge and eventually springs leaks.  What really happens is the coil will freeze in multiple area simulaneously and it's the pressurebetween these areas that causes the tubes to swell and eventaully brust.  These are very easy to spot as the leaks will run the length of the tube rather than around the tube. 

Make sure that you HVAC contractor is keeping your coils in top shape and keeping your HVAC system at peak performance.  Inspecting them now after a summer of hard use can identify issues that may crop up during the heat of next summer.  For more information on EES Facility Services' Preventative Maintance Programs, contact Martin Stewart today.

Read 2258 times Last modified on Thursday, 08 October 2015 17:00
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