To Pitch or Not to Pitch....

Recently I spent some time measuring replacement opposite ended steam coils for a local university. After years of use and poor drainage, the damage to the coil was just to much. 

Steam coils are great for heating and process applications. The most important factor to the longevity of the coil is to get the air and condensate out. There are several steps one should take to get the condensate out.

1. A properly sized drip leg - This allows the condensate to flow out of the coil and offers a place for any dirt to collect. 

2. A properly sized steam trap - This allows the condensate to be returned.  Size the trap appropriately and take note if the steam pressure is modulating. 

3. A vacuum breaker - This allows air to enter the system when a vacuum is pulled. When the steam is turned off, condensate is sucked back up into the coil and then sits there until the steam is turned on again. Standing water in coils cause carbonic acid which eats the coils and water hammer (nothing like blown out return bends)! 

4. Pitch the coil - Some manufacturers build replacement coils with the core pitched in the casing. Others don't and expect the fitter to pitch it in the field. Either way, a pitched coil will last longer and perform better. 

Here are some pictures of what can happen to a coil that is not draining right. 

10uta