20 T Voyager cap tubes restricted

[david j]

Hi folks
On Tuesday I'm scheduled to change out a coil in a 20 Voyager. As I understand it, lightning hit the unit about 2 years ago and the compressers were replaced. I went on a call for it freezing up and found the 24 captubes restricted. We have put in shell dryers in the suction lines and added acid neutralizer, and no improvement.It occurs to me that the carbon molecules from the burnout are too small to be caught by the filters. Any thoughts on this? And, since the unit didn't get a good cleanup after the burnout is this likely to happen again? I'm starting to get nervous.

Thanks
dave

[rob10]

We have done changeouts like this. But we fabricated a header with a TXV to replace the original.

[sonc]

A 20 ton unit with cap tubes? You mean distributors?

[david j]

The unit has cap tubes. It's about 10 years old. And Trane's cost for two cap tube assemblies is about the same as a new coil with the cap tube assemblies already installed.

[freonrick]

most of the tranes are using an orfice at each inlet of the coil, the tube before it looks like a cap tube. when you make the repair install a liquid line drier that can remove acid and wax from a burn out. from the drier run new copper to the new metering device whatever your machine will have when your done. replace the suction core drier with the burnout core. after a few days remove suction drier core and leave out. replace liquid line drier once more.

[airworx]

you needed to install high acid driers in liquid line.
did you take out the suction driers after 24 hours.
driers in the suction line are not needed and you are supposed to remove them after a day or 2.
when you have a burn out hi acid liquid driersare sufficient.
the captubes are probabley stopped up because of the windings breaking down. did yall install liquid driers or just suction.

[david j]

Just to be clear the tubes are about 1/8 inch OD, no crimped-in pistons like most Tranes. When the compressers were changed liquid line filters were installed but not suction. I can't remember now but they were probably standard filters. And I don't know who did this repair other than it was one of "us". I don't think any of our (current) guys would have left the unit with a 40 degree SH. So this problem took at least a little time to develop. And to get to the cap tubes this stuff had to get past a filter. Also, the restriction is either uniformly distributed along the cap tube or consentrated at the exit end where the liquid flashes. So the stuff must be VERY small.
Do I just worry too much?
I hadn't thought of changeing the liquid line. I'll probably do that.
I plan to do a little exploritory surgery on the old coil after its out. If I find anything of interest I'll post.
Thanks.

[Edited by david j on 07-25-2004 at 10:08 PM]