ReplyNot familiar on that unit, but as long as its setup for floating control, it should definitely be constant supply.
Professional Member
Performing PM's at a site today ran into an issue with a Trane Varitrac:
part# x13650529-01
My issue is that the bypass dampers(twined together) are not receiving 24VAC from the TB4 terminal, is this supposed to be a constant supply or is there another reason I would not be receiving power? It is a 3 wire control 24V,Open,Closed. I removed the connections from the board to see if that was an issue but still no power. The computer system show my modulation from 0-100% so I know that it should be modulating.
I'm not very proficient in controls so any help would be a appreciated.
Regular Guest
Not familiar on that unit, but as long as its setup for floating control, it should definitely be constant supply.
Professional Member
When you say "Varitrac" you are talking about VAVs and a RTU. I just want to be sure this isn't a CCP setup you are dealing with as they are two different things.
This says to me that it is a CCP set up. Normally in a CCP setup (at least the ones I set up for Trane) the bypass damper does need 24V as it does modulate to control duct static pressure for the VAVs to opperate correctly.My issue is that the bypass dampers(twined together)
Professional Member
Let me correct myself (proofread before posting...I am an idiot ~hangs head in shame~)...
No there may NOT always be 24V for the damper IF it is not spring loaded. The actuator controlling the damper will run for a set amount of time, i.e. a 90 second actuator will run for 45 seconds to get to 50% and may need calibration from time to time, then drop power to get it to stay in position.
David
Professional Member
A CCP is a Varitrac panel. They are called Varitrac CCPII(old) or CCPIII(new). Old talks to Tracker and Summit, new just talks to Tracker.
The output is a triac. It powers both sides during non run condition. When it needs to drive, it breaks common to one side to drive the other way for "X" amout of time. I think they are normally 90 seconds.
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wow, not sure if I should get involved in this mess....
Professional Member
I have started up several Varitrac(CCP) panels but it has been a while. If I am wrong, please post the correct info. I am trying to help the guy.Originally Posted by mallron
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The manual is on tranes webaite under literature. Search for CCP.
If the static/velocity sensor fails, the bypass will drive to its programmed "safe" condition and stop. Do you have a valid reading for static?
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The best way to test the operation of the bypass dampers is to turn off the power to the CCP (central control panel) than start it back up. When the CCP is powered up it will go into a calibration mode. First with the fan off it will open all vavs and bypass dampers. Than it will start the fan and close the bypass damper and after a few minutes it will resume normal operation.
The actuators should only have power when they are moving open or closed.
Professional Member
Sounds like dts2620 has been dealing with more CCPs and more recently than I. Hope things work out for you.
David
Professional Member*
You're right, my comment didn't help any, I should have kept it to myself or posted a comment that would have helped.
Anyhoo, some good advice has been given, so I guess it's all good.
Professional Member
Not sure if my comment did either. I wasn't trying to argue, just trying to help solve the problem. I thought that I remembered the output being a triac like a TUC but if it does not have power under off condition, I am wrong. It has been several years since I touched one.
New Guest
Hi, Was wondering if anyone came across this issue. Working on Trane Vari-trac 10 panel, having issues with the static pressure setpoint multiplier the range is 1.0 to 2.0 however fan static pressure setpoint won’t read pass .50 in w.g. Causes the bypass damper staying at 100%open.Any ideas thanks
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