ReplyIf your changing your sheaves every 6 months, Then you have a serious misalignment going on. Sheaves aligned correctly should easily last 3-4 years.
Regular Guest
Hello,
I have a problem with a Trane YSC120A4RMA39D00000000000 D. The problem with it is when the blower kicks on it sounds like a ton of bricks is dropped on the roof. I've observed the operation for about a year and the belt and pulleys have to replaced every 6 months. The cycle times aren't short. It runs pretty good in that sense. I'm wondering if I can install a soft start relay or even a small Hitachi VFD would be an option to ease the starting to prolong belt and pulley life. What do you think?
I was trying to do some research on the matter and was hoping Trane had something but, it seems they don't. I saw something online about "Soft Start Capacitor" but, googling that only yields soft start relays. Could I get some info on this item? Would that be the best seeing as a VFD inside a RT unit probably won't last in summer and winter temps.
Professional Member
If your changing your sheaves every 6 months, Then you have a serious misalignment going on. Sheaves aligned correctly should easily last 3-4 years.
Professional Member*
I would first check into what has been stated. I also wonder about the cycle time that you referred to. I would think the supply fan would run continuous during occupied mode and then fan starts during unoccupied to maintain lo or high night setpoints. I think VFDs are a great upgrade for many applications. Noise at start would be eliminated wear reduced and starting amps greatly reduced. I would consider VFDs. Speeds can be adjusted for filter loading.Originally Posted by 1SikLBZ
ckartson
I didn't write the book I just read it!
Professional Member
If its not cycling much but parts are getting chewed, its misaligned like ckartson said or the tension isn't right and its slipping.
Professional Member*
if it is one of many up there might be counter rotating in the off mode from the building pressure rising up thru it
"when in doubt...jump it out" http://www.youtube.com/watch?v=U1qEZHhJubY
AOP Committee/Professional Member*
Is this unit using an "a" or "b" belt?
Professional Member*
Verify alignment, Check for counter rotation, Quote a soft start and a VFD drive. Had a cooling tower once that liked to throw the drive shaft and people in the parking structure crapped their pants if they were near it. Soft start made repairs go away.
Economy - Quality - Speed <---- pick two
Regular Guest
if you go with a drive you can mount it in the blower compartment and add a remote panel for the lcd in the electrical cabinet. the factory mounts them in this manner and I have done a few retrofits this way. the blower compartment will have better temps for the drive than mounting it outside in a electrical cabinet.
forgot to mention, drives produce 3phase outputs. if you have a single phase unit you will need to change the blower motor and get the appropriate drive to run it on single phase.
AOP Committee/Professional Member*
Have you removed the rear panel and checked the rear bearing? That panel is a SOB to take off, so no one ever checks it.
Regular Guest
Trane puts VFDs on most newer larger RTUs. You can pick up a TR200 from your local Trane parts center, and as someone posted earlier you mount it in the supply cabinet and run the display to the control cabinet. But in all honesty its sounds more likely that you have an alignment issue.
Regular Guest
Did we come to a conclusion on this issue? From reading posts I would be checking mechanical first? Good luck!
Regular Guest
Looking at the control display for that Trane VFD, that looks exactly like a Danfoss FC300 series display or LCP as Danfoss calls them. Since Danfoss is about an hour away, I'd like to see what they offer.
No solution even 2 years later. It's not a high priority for anyone since the unit is only used for cooling since there's a condensing boiler and radiators for heating. We just figured out a different issue with the roof top unit. Everytime it would rain or outside had high humidity, indoors was swampy south Florida like. Turns out the OAD system i guess was set up for place like Arizona so, we would always be pulling outside air in regardless of outside humidity. I didn't personally change the setting but I guess there are different environment settings on the controller that were not set up correctly in the first place.
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