Thursday, February 19, 2015

Terminal Units: Knowing when to 'Flip-out'

Let's examine a practical scenario that gives you more insight into terminal units:  

You have double-checked your terminal unit order to make sure every detail has been provided. The material, voltage, accessories and controls are selected. Knowing that everything has been evaluated and entered correctly, the order is submitted. Now, on to the next one!

Later, you receive a call about the order you so confidently completed. On the other end of the phone is the installing contractor, and he is flipping-out! This is actually more literal than figurative. 

The units are said to not fit into the allocated critical spaces, due to an improper handing specification. Controls were ordered for the right-hand side, but they have arrived on the left.

Maybe the piping for the hot-water reheat coils should be on the left, but the connections were shipped on the right. All of a sudden, a seemingly minor detail has become a massive emergency. What can be done?

Determining the Solution:

Do you have what is needed to extinguish the fire? Although not every unit can be rotated, it may be possible in your case. 

There are important aspects to understand when deciding if a unit is able to be flipped from its intended working position. We will examine this, unit by unit.

Cooling Only Units:

Single-duct terminals (ESVs) can be turned 90°, 180° and every other degree in between. They do not have any position-sensitive parts or equipment that prohibits their mounting orientation. Further consideration, however, is needed when you add controls to the unit. Pneumatic controls are position sensitive, meaning that PESVs must be adjusted before they are rotated.

Fan-powered boxes may only be rotated 180°. You must take into consideration that all of our units do not have top and bottom accessibility.

TFS & TFS-F units have top and bottom access panels, which allows for access to the motor – after rotation -- from the bottom of the unit. All other Titus fan-powered boxes are unable to be accessed from the top, unless the unit is flipped.  

Parallel units cannot be flipped, due to the gravity-operated backdraft damper that is installed on the outlet of the fan deck. This backdraft damper remains open if the unit is rotated, which hinders the unit’s performance. The position sensitivity of pneumatic controls is applicable to fan-powered units as well.

Units with Electric Reheat:

When it comes to units that utilize electric reheat -- single duct or fan-powered -- careful consideration must be taken. The airflow switch used in Titus’ electric heaters is position sensitive. You can rotate a unit with electric reheat, but you are limited to a full 180°. 

Any other mounting orientation has the potential to impede performance. The airflow switch is an important safety component for the heater. It is better to err on the side of caution and not get too creative.

If ever there is uncertainty, please contact Titus Terminal Unit Applications for more clarification.

Units with Hot-Water Reheat:

With use of hot-water reheat coils trending, knowing whether you can flip one has become a very vital piece of information. The performance of how-water reheat coils is integral to the overall functionality of the unit, so there is concern that flipping a coil will adversely alter performance.

Counterflow is the cause for this concern. Our 1-row and 2-row water coils are of a cross-flow construction, and we do not recommend rotating these coils. Titus does make left-hand and right-hand coils available for 3-row and 4-row. The thing to remember when flipping a water coil is the water always enters through the bottom and exits through the top.

A terminal unit that arrives on site with the wrong handing is not the end of the world. If you find yourself in this situation, remember it may be alright to flip-out!

Please direct questions toward Titus Communications ( and/or Titus' Terminal Unit, UnderFloor Air Distribution Product Manager Derrick Smith (

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