Tuesday, September 11, 2012

Tubing Clogs

Quite a few central vacuum service calls involve removing clogs from the tubing system.  While the biggest symptom of a clog is poor suction, that doesn’t mean that poor suction is always caused by a clog.  Check out this article for more information on some other causes of low suction, as well as a few home fixes to try. 
Properly installed systems, in my experience, rarely develop clogs.  Proper power unit sizing, careful fitting selection and tubing layout, as well as neat, methodical installation practices will all make it very unlikely that a clog will occur.  This is why JCV offers a lifetime guarantee against clogs in our installations.
Here are a few photos of installation errors that led to clogs:

This is a section of tubing removed from a vacuum system in a restaurant.  The power unit was located to the left, with inlet branch lines extending from the right and top.  The assembly consists of two 45-degree elbows, one 90-degree elbow, a tee and a coupling.  This would appear to be a proper installation, but the demanding use of a restaurant reveals a weak point…

Here is what the inside of the tee looks like from the right side.  Plainly visible is the large buildup of solidified grease deposited over the years.  The nature of the tee fitting means that debris is introduced to the main line at a 90 degree angle, and momentum causes it to hit the back wall of the tee before making the turn to go through the rest of the system.  Restaurant vacuum systems ingest small particles of food, as well as airborne grease, in addition to common dust and dirt.  This mixture adheres to areas in the tubing system where the air is forced to make a sudden turn, and over time hardens and builds up.  It’s easy to see how restricted the passage has become, leading to repeated clogs. 
The solution was to replace this section with a wye fitting, which introduces debris from the branch line at a 45-degree angle facing the main line.  This type of fitting is much less susceptible to this type of buildup, and will definitely decrease the need for future service on this system.  I also took the opportunity to use 30 degree fittings instead of 45 degree fittings on the left side of the assembly, and I installed the 45 degree wye in a horizontal position, which eliminated the need for the 90 degree elbow.  I don’t have an “after” photo, but needless to say, this system now works better than it ever has!


his section was removed from a residential system only a few years old.  Hairpins are just long enough to become wedged sideways in the tubing, and thus are a common culprit for clogs.  Even so, it took a sloppy connection to create the potential for this clog to occur.  Let’s look a little closer:

Notice how the end of the hairpin has lodged between the end of the pipe and the shoulder of the fitting, due to the pipe not being pushed far enough into the fitting.  When replacing this fitting, extra care was taken to push and twist the end of the pipe (after cutting it squarely with a tubing cutter, and deburring it for a smooth finish) completely into the fitting.  You can vacuum up hairpins all day long and they won’t get hung up in a properly installed system.

This last example wasn’t clogged, but it certainly needed to be replaced.  A child’s toy Matchbox car had been inserted into one of the inlets, and the momentum it gained while traveling through the pipe caused it to blow the side of this tee completely out!  It’s a pretty dramatic and unusual failure, but serves to reinforce the benefit of using a wye instead of a tee.  By forcing the object to make only a 45 degree turn instead of a full 90 degrees all at once, the impact on the back wall of the fitting is lessened.  There’s a good chance that a wye would have survived this treatment, and the customer could have avoided the need for a service call.