Trane VAV Box Retrofit

Some of us may have customers who have encountered the pesky old Trane VariCone or air valve style VAV boxes.  This outdated technology often consists of worn or broken end switches and/or burnt out damper motors.  Due to an overpriced retrofit solution from Trane, end users generally learn to deal with some of these boxes in their building just not working.  Here at Stromquist we can provide our customers with a relatively painless and low cost retrofit solution using Honeywell D690 dampers and  Honeywell ML6161 floating actuators or the MARD zone control damper assembly.

These 9 easy steps will get the box up and running.  The first install should take about 4 hours, and once your customers are familiar with the process they will be able to cut the retrofit time down considerably.

Step 1.  Determine the diameter of the box being retrofitted.

Step 2.  Provide the customer with the proper size  Honeywell D690 and Honeywell ML6161 actuator or MARD damper assembly.

Step 3.  Power down the VAV box, open the access panel at the bottom of the box, and disconnect the wires going to the floating damper motor.

Step 4.  Remove the duct from the inlet side of the VAV box, revealing the attachment hardware for the air valve assembly.  Unbolt and remove the cone.

Step 4.  After the air valve has been removed carefully, detach the air flow ring from the assembly.  If the air flow ring has been damaged or is badly clogged you can provide a KMC SSS-series differential pressure air flow sensor as a replacement.

Step 5.  At this point there are two directions the installer can go to attach the Honeywell damper to the box:

a) Option one is to attach a piece of sheet metal to the inlet side of the box with a hole cut in it to match the outside diameter of the round damper. Then insert the damper and attach it to the back of the box with angle brackets and use duct mastic to seal the edge.

b) Option two is to have the installer fabricate a flanged ring with an inside diameter matching the outside diameter of the new damper assembly and a flange that is wide enough to cover the excess in the opening left by the air valve.  Use sheet metal screws to attach and duct mastic to seal.

Step 6.  Notch the inlet side of the Honeywell damper and install the air flow ring or cut a 1″ hole in the inlet side of the damper and install the KMC SSS-series differential pressure air flow sensor.  Then hook up the air flow pick up tubes.

Step 7.  Install and/or wire the  Honeywell ML6161 floating actuator on the newly installed round damper.

Step 8.  Reconnect the duct to the inlet side of the damper and re-seal.

Step 9.  Change the run time in the VAV controller from 360 seconds to 90 seconds to match the run time of the Honeywell ML6161, and reconfigure for new air flow sensor if needed.

That’s it!  Less than 10 easy steps to retrofit the antiquated Trane air valve without replacing the VAV box!

For competitive prices and great service the HVAC and building automation control pros trust Stromquist @ Company

7 Responses

  1. Congrats. Nice Honeywell advertisement… The 4 hours you say it takes to install the replacement unit more than eats the price differential between this kit and the “overpriced retrofit solution from Trane”
    Where’s the positive in changing brands?

  2. Hi Hector,
    Thanks for your comment. We actually have an updated solution that I have not had time to post yet. The new solution which includes a round damper with the airflow sensor already mounted in the damper ( installing this seemed to be what took the most time for contractors) has reduced the time down to twenty minutes or less for the contractors who have tried it. The four hour was a worse case for most contractors, but not gavin to deal with the cumbersome Trane bellows type internals and expensive velocity reset controller was what drove most people to look for a simpler solution in the first place.
    Hey, I am not locked into any one solution, so if you know a better way please share with our community. Thanks agin for your comments !

  3. lol, just buy the backplate rebuild and new motor,soft duct will let you pull the whole valve from the inlet side. If you cant access the inlet side cut a hole in the bottom for access. Repair the vav and patch the hole. 2 hours at best

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