Trane Rooftop Systems and VFDs | EMA Inc.
EMA Inc.

Trane Rooftop Systems and VFDs

Trane Rooftop Units can be seen on numerous buildings as a means for single or multizone heating, cooling and ventilation. With various options to meet building requirements it’s no surprise that the Trane Units are so popular.

Most Trane Systems have a built in VFD to control the supply and exhaust fan motors. The units typically utilize a 0-10VDC signal and a pressure transducer which measures duct static pressure. The duct static pressure is used to control the VFD as required to maintain the set point static pressure.

So what happens when the VFD fails?

What many don’t realize is that when the VFD fails, along with repair options there are retrofit options where a different VFD manufacturer can be incorporated and still allow the Trane system to operate as intended. There is some engineering that goes into this and not all VFDs will work. However, EMA has for many years successfully removed the existing VFDs in the Trane Units and replaced them with new VFDs.

Recently the EMA NY Technical Team removed the existing drives from eleven Trane units and incorporated new Yaskawa Z1000 Series Drives into the existing system enclosure. After confirming the existing relays, capacitors and connection terminals were all in proper working condition the new Yaskawa Z1000 Series Drive was installed, tied into the Building Automation System (BAS) and the units made fully operational. (See image below)

Trane Rooftop Unit

Another thing many don’t realize is that routine preventive maintenance typically consists of work on the system including

  • Cleaning dirt and debris from inside the Trane cabinet,
  • Inspecting the Trane base pan for proper draining and restricted drain openings
  • Inspecting coils and cleaning if required
  • Inspecting the fan motor including the blades and belts for visible wear and lubricating if required
  • Inspecting the control box including wiring and connections on relays

(the above from the Trane Maintenance Checklist)

Many of our customers tell us the VFDs have not been a focus during these PM Services. Like any piece of electronic equipment, regular PM is required to ensure connections are tight, and debris is cleaned as a means to spot potential issues, reduce unnecessary failures, and extend the VFD’s life span.

If you would like to read more about EMA’s Preventive/Predictive Maintenance click the link below to read Top 5 reasons to PM your HVAC VFD or contact me for more information at

No One, Anywhere, is Better at Drives than We are.


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