How to Achieve Coil Capacity

swcoil_superadminCoil Construction, Finned Tube Coils, Heat Exchanger


A heat exchanger, and in the following example a finned tube coil, can only meet its intended performance capacity if the air side and fluid side parameters are “as specified”.  The specified parameters for all coils are selected to meet or exceed the intended capacity.  If the parameters are changed, the capacity will also change. How a coil works: Coils … Read More

DX Cooling Coil Split Circuitry – Why and How It Works

swcoil_superadminCoil Circuitry, DX Coils

A typical air conditioning system using refrigeration requires control at intermediate loads to properly function and operate through the entire load requirements from highest to lowest.  This is the reason why evaporator coils have two or more circuits  that match the unloading or compressor cycling on the condenser-compressor side of the system. For any AC system to work properly, the … Read More

Your Coil Specialists

swcoil_superadminCoil Failure, Coil Leaks, Corrosion, freeze event

More than 80% of heating and cooling coils in the HVAC industry don’t make it to old age and need replacing.  There are so many reasons why they fail prematurely that we can’t name them all in one newsletter.  However, we can review the most egregious ones in commercial and industrial systems. Coil Construction or Arrangement Years ago, HVAC coils … Read More

Effects of Water Removal and Water Carryover in HVAC Coil Sections

swcoil_superadminCoil Moisture, DX Coils, Finned Tube Coils


Southwest Coil has replaced thousands and thousands of chilled water and DX cooling coils over the last 4+ decades.  Many of these coils have literally fallen apart in their casings and support.  An  air handler process always includes  filtration, cooling, heating,  and the distribution of air to the space through a supply fan.  It is in the cooling coil area … Read More

Why Large Tube Diameters Work Better With Steam Coil Heating

swcoil_superadminCoil Construction, Coil Performance, Steam Coils

Steam Coil

America has been using steam heating for 120 years.  Much of today’s technology gains have been based on problem solving of inefficient systems and providing coil heat exchangers that improve both capacity and longevity.  I have personally seen many systems that never had a chance to work properly – due to use of an improper coil for the application or … Read More

Coil Failures – Look Before You Leap!

swcoil_superadminCoil Failure, Coil Leaks, Coil Materials

Dirty Coil

More than 85% of all coil failures occur prematurely. This means very few coils ever achieve the longevity that was originally intended. There’s always a rhyme and a reason for every coil failure, and most can be identified based on experience and coil application science. Let’s take a closer look at coil failures – noting which ones can be identified … Read More

You Have Questions… We Have Answers

swcoil_superadminCentral Station Units, Corrosion, Questions

Question Marks

Each month we publish questions we receive about coils and air handler systems and applications.  There are many installations that have inherent problems that can cause lack of performance and/or system downtime.  The following are some of the problems that affect many of our customers. We service many fan coil unit systems in apartments and condominiums in the Denver metropolitan … Read More

Letters to the Editor

swcoil_superadminAir Flow, Air Handlers, Questions


Every month Southwest Coil Company receives many questions regarding coils and air handlers.  We like to share these concerns and possible solutions with our customers, as you may also be encountering some of the same situations and find that our explanations are beneficial.   I’m the Systems Operator for a museum  that’s air conditioned and humidity controlled by massive 150-ton indoor … Read More

Existing Fan Coil Problems in High Rise Apartments & Condos?

swcoil_superadminCoil Failure, Coil Materials, Coil Performance, Coil Replacement, Fan Coil Units

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 … Read More