11VAV-SLM005-EN
Parallel
Fan-Powered
Feature
Evaluation
Factory-Commissioning
Factory-commissioning is more than just factory-installed controls! Trane takes great
pride in being the industry leader in factory-commissioned DDC controls. The
following table differentiates these concepts and indicates where options can be
obtained (either the field, or the factory):
Factory-installed Factory-commissioned
Transformer optionally installed X X
Wires terminated in reliable/ consistent setting X X
Controller mounted X X
Electric heat contactors and fan relay wired X X
Testing of heater contactors and fan relay X
Controller addressing and associated testing X
Minimum & Maximum airflows (occupied/unoccupied) X
Minimum & Maximum temperature setpoints
(occupied/unoccupied) X
Minimum ventilation requirements
(used to calculate ventilation fraction) X
Thumbwheel enable/ disable X
Heating offset X
Factory-commissioned controllers provide the highest quality and most reliable
controllers for your VAV system. Additional testing verifies proper unit operation
including occupied/unoccupied airflow, temperature setpoints, communication link
functionality, and output device functionality. The benefits of factory-commissioning
are standard on VariTrane terminal units with Trane DDC controls.
Perforated Liners
The intended use of perforated liners was for units that had a Mylar or Tedlar
insulation. Mylar and Tedlar insulation was found to have long-term durability
problems and would erode into the airstream over time. The perforated liner was
designed to hold the insulation with the idea to improve acoustical performance over
a dual-wall construction.
Today, if a perforated liner is specified, it is generally used to prevent possible tearing
of the insulation during installation. However, the perforated liner will still allow air to
penetrate the insulation and loft fibers into the air stream. The best solution is to use a
foil-face or dual-wall insulation option.
SCR Electric Heat Control
Trane does not offer an option for SCR electric heat control. Our competitors use SCR
electric heat control, which is very costly. We can achieve a modulating kW operation
using our DDC controls. Using pulse-width modulation, our DDC UCM calculates
how far from setpoint the temperature is and what percentage of the electric heat is
needed. The heater is then pulsed for a specific time period to satisfy the zone.
Suggested Spec
PULSE-WIDTH MODULATION (PWM)—At heating setpoint, energize first stage of
heat. The second stage of heating shall be energized based on time and temperature
deviation from setpoint. Duty cycle these stages on a three-minute window. Stage 1
shall modulate from 0–50 percent deviation and be on continuously above 50%. Stage
2 shall modulate from 50–100 percent deviation.
Lower Damper Leakage
Our damper leakage rate is 1% @ 3 in. wg and Nailor’s leakage rate is 2% @
3 in. wg.
Nailor’s higher rate is the result of an opposed blade damper design, which generally
has a higher leakage rate.
