About this same time, I was involved in a new dye house installation at a Lee’s Carpet plant in Glasgow, Virginia.  Five roof-mounted make-up air units had been specified, each with two steam distributing coils stacked on top of each other.  The consulting engineering firm had correctly shown individual steam traps for each coil of each unit

That following winter I received a call from the plant engineer stating that these units were typically producing a meager 50-55 F discharge temperature on a cold winter day.  It turns out that he was exactly right.  It also turned out that the installing contractor had taken a short cut to save a few bucks and had piped the two coils of each unit to a single steam trap. 
This is known as group trapping and it’s always a disaster! 

When the five units were repiped using individual traps for each coil, the units produced rated capacity and the problem was solved!  Forty years later, I still see many examples of group trapping.  Premature coil failure always results.  Salesmen who sell replacement steam coils just love these situations. If steam coils are piped properly, they will last indefinitely !

For another example of imminent steam heat exchanger failure, visit failure example #3

 

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