409 and cap tubes....

[Diceman]

Doesn't seem to be as big as problem with clogging as with 404 and some other blends, or am I dreaming?

[Dad]

Originally posted by Diceman
Doesn't seem to be as big as problem with clogging as with 404 and some other blends, or am I dreaming?

Not sure why a refrigerant type would be more subjective to blockage than others unless it is POE oil type. It is the heat and oil now a days that you must watch. Dark compressor labels are a dead give away and POE is the worst.

We get just as many 404 units as 22 as 134 that block yet we change a cap tube with every compressor change too.

[Yuma]

Just like R-12, the cap tubes did not clog up as much as they do now with the newer oils... (It's the oils).


Yuma,

[James 3528]

409 is good on counter tops

[condenseddave]

'tis the lubricant.

[icemeister]

I've had the most plugged cap tube problems on equipment manufactured in the early-to-mid 1990s. I changed out more caps between 1995-2000 than in the 30+ years before that. The newer units don't appear to have as much of a problem.

While I still believe it's all POE oil-related, the posts that our very own in-house oil guru, Roby, made a while back explained a lot about these problems when he said paraffin wax was eliminated from motor windings around ten years ago......primarily as a result of the effects of the POE oils on it. At least that's my take on what he said.

Make your own conclusions:

http://hvac-talk.com/vbb/showthread.php?threadid=78710

[dietz]

I have seen cap tubes come across my counter that when knocked on the couter mats have a grit like sand coming out of them. Almost 99% of the time it seems to be on POE systems.

Slightly off the subject... but still on cap tubes. I have a lot of guys calling up for cap tubes for a particular manufacture. I have found that SUPCO carries 5 different cap sizes that fit 99% of the apps out there. Basiclly they have a chart that you find the HP of the comp, and then the app (low,med,high) and then refrig and intersect these and it will tell you to use so many inches of # whatever cap tube. I have sold probably over 150 of these over the years now, and knock on keyboard... nobody has every brought on back !!! so next time go to your local counter guy / gay and tell them you want to try one of those, so you dont have to pay top dollar and wait x amount of days for the OEM to be shipped in.

[RobY]

Originally posted by dietz
I have seen cap tubes come across my counter that when knocked on the couter mats have a grit like sand coming out of them. Almost 99% of the time it seems to be on POE systems.

If the systems have bullet dryers with loose fill desiccant beads, I bet the sand is particles coming off the beads. You are more likely to see this if the dryer is mounted with the refrigerant flow going up through the dryer. Gravity pushes the beads down and the flow pushes the beads up causing them to move against each other. The rubbing beads will generate particles that move to the inlet of the cap tube.

POE has nothing to do with this problem, except the binders holding the bead together are slightly different in the HFC compatible beads, than in the old beads used with R-12 and R-22. The beads are made from molecular sieve particles held together with a modified clay binder. Some clays are stronger than others when dry, but may get very weak when wet. Other clays may give more balanced mechanical properties both wet and dry.

Molded core driers are not as prone to generating particles because the binders are stronger and the core can't rub against anything else, but they are more expensive than loose fill bead driers.

[big al2]

The local guy that knows everything about everything refrigeration says that "sand" is burnt oil. I have seen it in old systems without bullet driers.