Swimming Pool Filter pumps
The heart of your circulation system, your
pool pump pulls water from one or more suction ports (i.e., skimmer & main drain), and
then pushes it through the filter & heater (if you have one) and back to the pools'
How do I know what pump is right for
Contrary to the advice given when selecting
a filter, a bigger pump is not always a good thing. Unless you have been advised by a pool
pro, or someone in the know - that your existing pump was undersized, it would be wise to
keep the same horsepower and flow characteristics as you have now.
How do I know what Horsepower my pump motor
The horsepower should be listed on the nameplate
of the pump motor (in very tiny letters..hp). If the motor nameplate is burnt or worn off,
sometimes a part number of the impeller can tell us
which hp your pump motor is.
If the existing pump has done you well, it
is easiest to plumb and wire with the exact same pump. The heights and lengths are the
same, which makes the job a bit simpler.
Are all of swimming pool pumps the same?
All of the manufacturers of pumps
represented are Major Manufacturers; well respected, very large, international market
leaders. The motors used on the pumps are all nearly the same. There has not been any
really astounding inventions in pump technology in the last few years, so all innovations
have been implemented by most in one way or another. Each pump is slightly different in
its hydraulics, shape, basket and lid, and colors. But these may or may not matter a whole
lot. Read on for more substantial ways to discern between pumps.
You will find that there are low head
pumps for aboveground pools and medium and high head pumps for inground
pools. "head" refers to the flowrate, in a backwards kind of way.
- Aboveground filter systems and small inground
pools (under 10,000 gals) should use a Low Head pump like a Maxim, or Dynamo or Power-Flo.
- Pools from 10,000-20,000 gals can use a
Medium Head pump like a Superpump, a Pinnacle or Cygnet.
- Pools over 20,000 gals could possibly use the
High Head pumps like, Super II, Challenger, Ultra-Flo or the Sta-Rite pumps.
- Pool/Spa combos with at least 3 lines
influent and 2-3 back to the pool, 2" plumbing may be able to handle the Ultra High
Head pumps like Northstar and the Whisperflo.
Remember to match horsepower and pump type
and flow rate. Use the Flow Rate Charts, (see below) based on a sample feet of head
(vertical axis) of 40 or 50 feet. This is the only true way to compare pump to pump.
As Americans, it's natural to want the big
V8 powerplant, but a pump that is too powerful could actually prevent filtration while
damaging the filter and heater. Pipes or fittings could even be blown apart. When matching
pumps to filters, check the Design Flow Rate of the filter from the nameplate. The average
flow for the pump you select, should be within 10% of the filter's Design Flow Rate.
Remember also that a smaller hp motor is
going to draw fewer amps, which is going to cost less to operate. If you are careful to
match up flow charts, you could actually reduce the hp required, while increasing the head
of the pump. For instance, a 3/4 hp Whisperflo produces the same amount of flow as a 1.5
hp Superpump. So, you could replace one with the other, while electrical costs are nearly
cut in half!
So, when selecting a pump, keep it close to
the original specifications, and use the Flow Charts. Most systems could handle
a small increase in pump size, especially if you are replacing the filter with a larger
The water is moved by a brass or plastic
impeller that is shaft driven by an electric motor. On the way to the pump, the water is
under suction or vacuum. After the impeller the water is now under pressure until it is
released into the pool. The 3/4 - 2.0 hp motor is powered from a breaker on your electric
panel (or fuse box), at 115 or 230 volts. Usually motors over 2 hp need 230V power to
operate, and most smaller Hp pumps convert to accept either 115 or 230 volts. Above ground
units may plug into an 115V GFCI outlet. (Be sure to buy a Pump that will match the
correct voltage going to your existing power supply). Electrical consumption will vary by
area, however, manufacturers have been designing motors and pumps (the wet end) which are
more efficient and consume much less energy than older pumps. The smaller the Amp draw of
the motor, the less expensive it will be to operate.
How long do motors last?
Motors typically last an average of eight years
before needing either rebuilding or replacing. Noisy, screeching front and/or rear
bearings will let you know when you need to do something.
PUMP TROUBLESHOOTING GUIDE
Leaking pump? A very common problem is the threaded fitting carrying water out
of the pump shrinking and allowing water to drip, run and then spray. This can be replaced
with a high temp fitting to prevent its reoccurrence. Approximately $10 parts and one hour
labor. Water may also leak from a worn out mechanical seal. This seal is the separation
between the wet end and the dry end (motor) of the pump. This mechanical shaft seal should
be replaced. Approximately $12 for the seal and one hour labor.
Air in pump basket? The pump is meant to operate air free. After some time, you may
notice air in the basket, especially if you have a clear lid to observe such things. This
can reduce filtering efficiency, allow dangerous air to build up in filter, and sometimes
prevent your pump from catching prime (being able to move water). The problem is usually
located around the pump, aboveground. Occasionally, we have to look underground for the
source of the air. Air in the pump basket can be caused by something as simple as the
water level being too low in the pool. You might also want to check the skimmer weir. This
is a plastic flap at the throat of the skimmer that keeps the debris in the skimmer when
the pump is off. If the skimmer weir is stuck it can cause the skimmer to drain and take
in air. Also check that the pump basket lid is on tight and the o-ring is lubricated. See
below for more tips on locating air leaks in pool pumps.
Pump is not pumping water like usual?
Check your skimmer baskets for heavy debris. Make sure
the pump basket is clean and properly positioned. Some types of pumps have a pump basket
that locks into place to prevent the basket from floating and causing the pump to
cavitate.(starved for water) Sometimes when we get repair calls like this we'll find that
the pump basket is cracked and it is allowing debris to clog the pump's impeller. To check
the impeller, remove the pump basket and reach into the volute and feel if it is clogged
with debris. (turn motor off first! ;-) If you cannot feel for sure, you may need to
remove the motor from the pump to properly inspect the impeller.Many times you need only
remove a clamp band to separate the motor from the pump.
Noisy Motor? Inside of your pump's motor are a front bearing and a rear bearing. These
bearings are sealed and cannot be re-packed or re-lubricated. They are replaced when they
begin to scream and screech. Bearings can become damaged when the pump has run dry and
overheated, or if the pump is put under high loads. A local motor shop can replace the
bearings for you, usually for under $100. One test you can do is to remove the motor from
the pump, and turn it on. If it still screeches (while not pumping anything) it is going
to be the bearings. Rebuild it, or better yet, just replace the motor. A noisy pump can
also be cavitation. This sounds less like screeching and more like grinding. This
condition is caused by starving the pump for water. If possible, open more valves, or find
the cause of the obstruction that is blocking water flow into the pump. It may be the
impeller. Finally, noisy pumps can be the sound of components striking one another. The
impeller can, on stub shaft models, come loose, and hit against the impeller housing. The
internal fan can break and hit against the motor side. Both instances will resolve
themselves. At 3450 rpm, it won't take long for the fan to wear down or the impeller to
chew right through the housing. These conditions are rare, and probably will require a new
Motor will not start or turn on
First check that you have power. Is the breaker
on? Timeclock on? All switches on? Use an electric meter to be sure that voltage is
correct. Check that all electrical connections are tight and not corroded or shorted out
by bugs or debris. Again, the use of a meter or test lamp will check this with certainty.
If there is power going all the way to the motor, the motor may have become shorted across
Motor hums but will not start The impeller may be clogged with debris. Turn off the power,
and spin the impeller shaft. If it won't turn freely, remove the motor from
the pump and clean the impeller. If it does spin, check the capacitor. If it is a
stub shaft type motor, check that the impeller is not hitting the impeller housing.
The capacitor is the black cylinder on the
back of the motor, although sometimes it is silver and mounted on top of the motor. Check
the capacitor for white residue or oily discharge or for bulging. Sometimes even a fine
looking capacitor can be bad. Replace with a new capacitor of the same rating.
Finally, low voltage can be a cause of a
humming but not starting motor. New motors are wired 220 volts, so if you hook it up to
110 volts, it will only hum, or cycle. Or perhaps one of the power leads is loose, or
shorted. Check with a Multimeter to verify the correct voltage, with a variance of 10%
Motor Cycling If the motor runs for a short while, shuts itself off, and
turns itself back on later, it may be overheating. Normal motor temperature is over 140
degrees, so all motors run hot. But a cycling motor may indicate that the thermal overload
is kicking it off. If this motor was just replaced, make sure that the electrical supply
connections are correct and the wire size is correct for the voltage it is carrying. Low
voltage can cause overheating. Inadequate ventilation can cause overheating, so make sure
that the air vents are unobstructed. Usually, old motors that suddenly begin to overheat
will need to be replaced. They usually have a short inside, across the windings. And
motors are just not rewound anymore like they were in the old days.
Swimming Pool Pump Installation
Plumbing in a new pump motor...
Cut the pipes going into the front of the
existing (old) pump, and the pipe
coming out of the top. Choose your cut location so as to allow room on
either side of the cut to glue on a repair coupling. Remove the wires and
the conduit adapter from the rear of the motor. Remove the MTA fittings
threaded into the front and top of the old pump. Using Teflon tape and
perhaps also silicone sealant, thread in the fittings you removed from the
old pump. Note: Do Not Overtighten. Only 1 1/2 turns past hand tight. Using
rubber mission couplings, pvc unions or simple slip x slip couplings,
reconnect the pipe you cut. On pvc fittings, use a good primer, and good,
fresh pvc glue for pressure applications.
Wiring up a new pump motor...
First, screw in the conduit adapter onto the
back of the motor. This
adapter is usually removed from the old pump and screwed into the 3/4"
threaded hole where the wires enter the back of the motor. Some motors offer
an additional port of entry on the top for wiring flexibility. Remove the
back of the motor and run the wires in through the adapter, and tighten down
the threaded connector to secure the wires and keep out moisture and
insects. Notice where the wires enter the back of the motor, on the right
side, a terminal board that has 2 brass screws for clamping down the 2
wires (lines) coming in. It doesn't matter which wire goes to which screw.
Above the terminal board there is a green screw that is for clamping down
the ground wire.
All pump motors are wired to receive 230 Volts from the factory. That is, 2
lines (wires) carrying 115 Volts each. So, you need to know if you have 115
Volts coming in, or if it's 230 V. Usually 230 Volt service will have 2
wires of the same color, (and one green ground wire), while 115 V service
will have perhaps one red (hot) and one white (neutral), and one green. You
should use a meter to be sure, but you could just look at the breaker. If 2
of the wires come off of one breaker, then you have 230 V. If one is
connected to a breaker, and the other to the 'neutral' Buss bar, then it is
115 V service. Or look at the voltage plate on the old motor and see how it
was hooked up. Matching the Low Voltage diagram (115 V), or matching the
high voltage diagram (230 V)?
If you have 230 V service, hook up the wires coming into the motor to the
brass terminals described above. If you have 115 V service, follow the
instructions on the motor label to switch the motor to receive 115 V. This
is a very easy switch of only one wire. Again, the motor comes factory wired
for 230 V. If you are connecting 115 V to it, then switch the motor first.
Putting 230 V into a 115 V motor can damage the windings, and perhaps fail
the motor. After switching the motor to 115 V, then connect the power wires
to the brass terminals as described above (again it doesn't matter which
wire goes to which screw).
To replace or rebuild your motor? For most all rebuilds of your motor,
expect charges of $100 to have a motor shop rebuild a motor (which you bring to them and
pick up later). Theoretically, the motor will last another eight years, but the warranty
is only 90 days. ;-} Replacing the motor with new would cost $131 at poolcenter.com for a 1 hp AO Smith motor. The warranty on a
new pump motor is 2-3 years for most manufacturers. Whether rebuilding or replacing
the motor, the Mechanical Shaft Seal should also be replaced (see below).
Swimming Pool Motor Replacement (not
the plastic wet end, just the motor)
Having learned how to remove and break down
a pump and motor in the previous sections, replacing any of the components is simply a
matter of disassembling the pump down to the component that needs replacement, getting a
replacement part, and reassembling the unit. Of course, if the entire pump and motor is to
be replaced, you purchase the replacement as a unit and plumb it in as previously
Sometimes the motor will trip the circuit
breaker when you try to start it. If this happens it is usually because there is something
wrong with the motor; however, it could be a bad breaker or one that is simply undersized
for the job and has finally worn out. To replace the motor here is the procedure:
- Break down the unit as described in the
section on changing a seal. Remove the shaft extender by removing the Allen-head setscrews
and pulling the extender off the motor shaft. Sometimes this might need persuasion. Use
your large flat-blade screwdriver to pry the extender away from the motor body. Sometimes
corrosion will eat away at the setscrews and extender-if it is too tough to remove,
- Before sliding the shaft extender on the new
motor, clean the motor shaft with a fine emery cloth such as you might have in your copper
pipe solder kit. Apply a light coat of silicone lube to the shaft. When you put the
extender on the motor shaft, the setscrews go into a groove that runs along the shaft.
This groove allows the screws to grip and not slide around the shaft.
- Now slide the new extender in place, lining
up the setscrews along the channel, but do not tighten the setscrews. When you have
reassembled the bracket and seal plate, seal, and impeller, you can adjust the impeller to
just barely clear the seal plate face, then tighten the setscrews. Be sure the impeller is
screwed tightly onto the shaft extender before making this adjustment. If it is loose,
when the motor starts it will tighten the impeller, by turning it tighter against the
extender, thereby tightening it against the seal plate, seizing up the unit.
- Secure the shaft extender with your pliers or
3/8-inch box wrench and lay a rag over the impeller. Firmly hand tighten it. Reassemble
the remaining pump parts and/or replumb the entire unit back into place.
- Follow wiring instructions above, in previous
section on installing new pumps.
Lubrication...I always try to stress to pool
owners that a lot of air in the pump or loss of prime problems are due to lack of
lubrication on the pump lid o-ring. Lubricants like Magic Lube (Teflon based) or Jack's
Lube are always a great choice. Remember that a little dab will do the job. Never use a
petroleum based product (i.e. Vaseline) for lubrication on o-rings. Inspect the pump
o-ring for cracks, splits, or pinch marks. Finding little problems can prevent big
problems from occurring.
All pumps have seals to prevent water from
leaking out along the motor shaft. When these wear out due to overheating, they are easy
to replace. The first thing to do is to turn off the electricity to the motor at the
- 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 volute. Wiggle it slightly from side to side as you pull back to help break
- 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. Note 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 flatblade 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
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
Remember to use only non-hardening silicone
lube like Magic Lube on all pool and spa work. Vaseline or other lubricants are made of
petroleum, which eats away some plastics and papers.
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:
- 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 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 called "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 $9.95 + 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.
Make sure the water level in the pool is
high enough, and that the skimmer weir is not stuck in the up position. Make sure that the
incoming and outgoing valves are in the open position. If you suspect a clogged line, you
can purchase a Drain King at a local hardware store to pressurize the line backwards from
the skimmer towards the pump and remove leaf/debris obstructions.
You may have an automatic pool cleaner (a Polaris) that requires a booster pump. It looks different from
your filter pump because it doesn't have a strainer basket. All else is the same, however
it should last longer if it's being used only a few hours per day.
Never operate the booster pump without the
filter operating and providing it a constant flow of water. If you have time clocks,
synchronize them to ensure this doesn't happen. Otherwise, you will probably burn up the
shaft seal, and possibly damage the bearings.
If your pool has an attached spa, you may
have a forced air blower motor sticking up above water level. This is connected into the
spa jets (return lines) to provide turbulence and air therapy. If your blower motor isn't
working or is very noisy, it may need rebuilding or replacing. Prices and warranties are
very similar to filter motors. Before calling for service on any motor, check that
switches on the motor are on, breakers are on, spa side or indoor remote controls are on,
and the timer is on.
information provided courtesy of poolcenter.com