Pool Pumps – Clogged Line

Clogged intake line

The first step is to verify that there is indeed a problem.  If we suspect a problem with a skimmer line, we will shut off the other
intakes and try to run the pool pump off of that skimmer line alone.  If the flow is completely cut off at that point, then the clog is obvious.  If there is
still a question, then try the same thing with the other skimmer or the main drain. 

Some higher HP pumps will not run very well off of one intake
alone, but comparing the flow of one intake versus the other should give a pretty fair idea of whether or not there is a clog.

The easiest way to remove a clog is to use a drain jet to force water against the clog to remove it. The direction of the flow of water
should be opposite to the normal flow.  In other words, reversing the flow of water is one key to removing the clog.

To remove a clog in a skimmer, turn off the pump and open up the skimmer line and close off the other intakes.  Remove the pump lid
and put the drain jet into the intake port on the pump and turn it on.  This should cause water to flow backwards through the pipe and may dislodge the clog. 
Make sure that water is coming up through the skimmer port and not returning through the other skimmers or main drain.

It is often necessary to allow pressure to build up in the lines to “blow” out the clog.  With water running through the
line, hold a tennis ball over the skimmer port in order to temporarily block off the flow.  When the pressure builds up in the pipe, remove the tennis ball and allow
the pressure to be released.  This blast of water pressure will help to dislodge the clog.  It may be necessary to repeat this process several times in order to
remove the clog.

If this process does not remove the clog, then it may be necessary to use a CO2 gun to blow out the clog.  This should only be done by
a pool professional.  The CO2 gun is capable of producing a 350 PSI blast of air pressure.  The line is filled with water, then the blast of air pressure is
released.  Since water does not compress, the “shock wave” is carried directly to the source of the clog.

There is not a lot of danger associated with this procedure, if it is done properly.  We usually do not use more than 120-150 lbs of
air pressure at one time.  The only possible problem that can develop is that it can blow apart a faulty (loose)  pipe joint underground.  This is not a
common occurrence, but it is a remote possibility and the homeowner would need to pay for a repair in such a scenario.

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