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Pumps & Motors
(cont.)
All pumps have seals to
prevent water from leaking out along the
motor shaft. When these wear out due to
overheating, vibration or a sudden
change in water pressure - you will need
to replace your
pump shaft seal. The first thing to do is to turn off the electricity to the motor at the
circuit breaker.
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To access this seal for replacement, remove
the four bolts that hold the pump halves together, it is not necessary to remove the
entire pump from the plumbing system.
-
Grasp the motor and pull it and the bracket
away from the pump volute. Wiggle it slightly from side to side as you pull back to help break
this joint.
-
Take
your pliers or a wrench and hold the
shaft extender to prevent it from
turning. Unscrew the impeller from
the shaft extender using an impeller
wrench. You can also wrap a rag over
the face of the impeller so you
don't cut yourself and twist it off
by hand. As a last resort, hold a
large screwdriver against the
impeller and tap it gently with a
hammer. Use care not to damage the
impeller. Use even more care that
the screwdriver doesn't slip and
damage you.
-
Remove the four bolts
that hold the bracket on the motor.
If needed, use a hammer to gently
tap the bracket away from the motor.
-
Remove
both halves of the old seal. Notice
how each half is installed so you
get the new one back in the same
way. One half is in the back of the
impeller and is easily popped out
with a flat-blade screwdriver. The
other half is in the seal plate and
motor bracket unit. Lay the bracket
on your workbench with the seal on
the bottom. You will see the back of
the seal through the hole in the
seal plate. Using the flat-blade
screwdriver once again, put the tip
on the back of the seal and tap it
with a hammer. It will pop out
easily.
-
Install the new seal.
First, look up your pump in the
manufacturer's literature or supply
house (Poolcenter.com!) catalog to
determine what model seal you need.
Clean out the seal plate and
impeller where you have just removed
the old seal. Use an emery cloth or
a small wire brush and water. Dry
each area and apply a small amount
of silicone lubricant to help the
new seal slide into place. Install
each half of the seal the same way
you removed the old one, white
ceramic of one half facing the
glazed carbon ridge of the other
half. Use care in installing not to
damage, nick or soil the face of
either seal half.
-
Gaskets. When you
break apart a pump, the old gasket
usually won't reseal. Clean all of
the old gasket off of the seal plate
and volute. Scrape it clean if
needed with a flat blade
screwdriver. Now reassemble the pump
the same way you took it apart,
placing a
new gasket between the pump
halves.
-
Check for leaks by
starting the pump and let it run
several minutes. A fresh paper
gasket might leak for a few minutes
until it becomes wet and swells to
fill all the gaps, but it should
stop leaking after a short time. If
your job does leak, take it apart
and go over each step again, making
sure the seal halves are seated all
the way and that there is no
corrosion or debris left in the
impeller or seal plate that might
prevent the new seal from seating
completely. You may add some Blue
RTV silicone sealant to help a paper
gasket.
In some
pumps where the parts are assembled
differently, you follow the same steps.
The clamp is removed to disassemble the
pump halves, and you must remove the
diffuser to get to the impeller. To
remove the impeller you can grip it with
your hand and twist it off, but the
trick with these units is to stop the
shaft from spinning as you twist off the
impeller. There are air vents in the
motor on the end closest to the pump
itself. Look in and you will see the
motor shaft. Place a flat-blade
screwdriver in one of the air vents and
wedge it against the shaft to keep it
from turning.
Alternatively, you can remove the end cap
and look inside as you twist the impeller. You will see the back end of the shaft, with
the start switch attached. Since this switch is fragile, you must remove it (one screw) to
access the slotted screw in the back end of the shaft. Place the screwdriver in this screw
to keep the shaft from turning as you remove the impeller. Or use a 7/16" wrench on
the back of the shaft.
Instead of a
gasket, some pumps use an
O-ring. Clean this and
lubricate it before reassemble. If it has stretched and it seems
like there is too much O-ring for the channel in the volute, try soaking the gasket in ice
water for a few minutes to make it shrink a bit.
Some pumps use a plastic impeller with a
housing that holds half the seal in place. If the pump has run dry and overheated the pot,
this housing might be warped and the seal will not fit tightly. The only solution is to
replace the impeller. This is a common problem with automatic cleaner pumps, which are not
self-priming.
Remember to use only non-hardening silicone
lube like
Magic Lube on all pool and spa work.
Make Sure not to use Vaseline or other lubricants that are made of
petroleum, which eat away some plastics and papers.
Clogged
Impeller?
When your pressure is high, your filter is
dirty, right? When your pressure is lower than normal, your pump basket is dirty. If the
basket is clean, yet pressure and flow is still low or surging, you may have an air
problem or the impeller may be clogged. Something prior to the filter is obstructed. To
unclog an impeller follow these steps:
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Shut off power, remove motor and seal plate
from pump. Sometimes this is one clamp that holds the motor to the pump, or some pumps
have nuts or bolts to remove.
-
Stand motor on it's end, remove any diffuser
or impeller shroud, and using needle nose pliers or a thin screwdriver, remove the clog.
Run some heavy wire through the vanes of the impeller.
-
Reassemble pump snugly and tightly. Fill pump
pot with water. Restart pump. Pressure then should rise.
Locating
an Air Leak...
Make sure the strainer lid is on tight, with a
clean, lubed o-ring. Also check that all plugs are tight. A good trick in
locating an air leak is to shut off the motor when it's under full
pumping head pressure, and look for water to spray back out of the void
where the air was entering. You have to
be quick to catch this spray-back! This
void will always be before the impeller.
After the impeller is what we call "the pressure side." Any
leak or void here will leak water out. Any leak or void prior to the impeller (in front of
the pump impeller) will draw air in when the pump is on. The pump will "pump"
air if it can, it is the path of least resistance. So, your system needs to be almost
airtight to run properly. When you find this void, patch with
epoxy putty or
silicone, or
replace the part if needed.
If that didn't work, you can do this...buy a
Drain
King at your local hardware store (or we can send one for $20.95 + S & H). This
connects to a garden hose and puts the line under pressure. Putting this in the skimmer,
you can turn on the hose and pressurize the line backwards (Also Great for clearing clogged
pipes). Remove the pump lid and use a plug at the pump entrance. This will allow
pressure to build up in the line and squirt out at the leak. Many suction side leaks found
in this manner are then repaired with
pool putty, or a more permanent plumbing repair /
pipe replacement can be made. (continued........)
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