If I’m lucky, a pipe
broke near our
chicken coup and the
leak caused my
protection system to
shut down the pump.
It could also be the
worst case scenario:
The pump has failed.
Not a big deal with a
shallow well pump,
but our pump resides
500’ below ground
and replacing it is an
So, over the 32 years
we’ve lived here, I’ve
developed a system to
protect the pump as
much as possible.
While I’ve employed
five main protective
components in the
system, readers may build their own systems employing as
few as two. The system diagram is shown in Figure 1.
A word about safety: While the working voltage on
larger submerged residential pumps is 240 VAC, all of the
control circuitry on my system operates at low current at
120 VAC. The components are mounted in grounded
metal cabinets with wire routing via metal conduit. There
is a nearby in-view power disconnect. The control circuitry
is mounted to a copper-clad board which is
also grounded. While the pump is fed 240
VAC via a 15A dual breaker, all of the
control circuitry runs at 120 VAC and is
fused at 1A.
(also called a
The first step in taking control of your
pump is to add a contactor which is shown
in Figure 2 to the right of the pump control.
A contactor is really just a high-current relay,
but with some added design features such
as no-bounce contacts and overload
protection. Those made specifically for
Purpose Starters. Pumps up to 2 HP are
often switched directly at high current by
the pressure switch, which feeds the pump
control box. The diagram in Figure 3 shows
how adding a contactor allows you to isolate the pump
circuit from the pressure switch.
While a standard pressure switch can handle a 2 HP
motor load directly, adding a contactor will take most of
the current load off the pressure switch and — most
importantly — give you a low-current 120 VAC method of
controlling your pump. The contactor I used also has an
internal thermal over-current relay. I chose a 7A thermal
July 2016 35
■ FIGURE 2. Pump control (left) is powered by the contactor (right).
■ FIGURE 1. Protection