There are
many reasons and causes of how air can get into the pool system and damage the
pump. This can happen over a period of time and might not be noticed
immediately. Over time this causes the pump to run dry causing damage
internally. Eventually the pump will start showing signs, some of which may
initially be loose top and front fittings on the pump, water leaking from the
mechanical shaft seal inside the pump, or the pump tripping the inside
electrical distribution board.
What is a dry running pump?
A pump
running dry causes the water left in the pump pot to literally boil. If the
pump is left to run, the boiling water becomes ‘super heated’ and turns to
steam. This steam melts plastic components inside the pump as well as fittings
and pipe work connected outside the pump. Boiling water is not as damaging as
steam, but over time can be just as devastating to the pump.
Low Water Level
If the
water level in the pool is too low, the skimmer box/weir and pipes could draw
air in, and the pump would also then draw in air. This could cause the pump to
run dry and overheat, causing numerous problems with the pump and fittings.
We are
finding that with the current water restrictions in the Western Cape, that many
people are continuing to run their swimming pools with the water level running
low, assuming that the water comes through from the bottom of the swimming pool
cleaner through the hoses and into the pool pump. This is unfortunately NOT the
case. The minute the water drops below the vacuum lid in the weir you are
allowing air into the system, which may result in your pool pump being damaged
internally.
An
overground suction line can be installed, which completely bypasses the weir
and runs directly from the pool into the pump. By installing this, along with
an inline hose basket, you can still run the pool system as per normal.
Loss of suction
If you
notice that the pool cleaner is not working very well, you might have air
getting into the system and this will in turn cause the pump to suck in air,
run dry, over heat and again cause numerous problems with the pump and
fittings. Causes could be low water, broken hoses, broken pipe work underground
(i.e. underground suction leak), a damaged or broken weir/skimmer box or even a
failed pump shaft seal. Debris in the skimmer/weir or pump baskets, as well as
in the pump’s impeller
If you
have a large amount of leaves or other debris in the pool, the baskets can overfill
and this can block the water flow causing the pump to run dry. If the impeller
is blocked by stones, leaves or other debris then the water flow through the
pump is also affected this could lead to the pump running dry as well.
Loose unions, fittings and o-rings
If your
pool pump is sucking air through the pump lid or o-ring then air is also
getting into the system, causing it to run dry. Air can also be drawn in
through loose unions or other fittings on the pump. Your pump can also draw in
air through a worn mechanical shaft seal while trying to prime. Once primed,
water can then be pushed the other way, into the electrics causing the pump to
trip. However, it can also be a slow leak that would not be seen from the
outside of the pump.
If the pump
has over heated external fittings need to be replumbed and the system then
retested to ensure there are no further issues with the pump.
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We hope
that this information is helpful and if any further assistance is required
please do not hesitate to contact us.
