Most contactors cost no more than $25 and can be installed in 15 Minutes or less.  
Total Job:  $65-$85
This is a contactor that has seen its last days.  I would
replace this now to save trouble in the future, and that future
would most likely fall on the hottest day of the year!

The contactor has both 24volt connections as well as high
voltage 240 volt connections.

If you are having a problem with ants in the contacts you may
want to think about getting a contactor which has sealed
contact points.  It only cost a few dollars more but will save
you time and money in the future because it is impossible for
ants or bugs to make their home there.
few minutes to replace and are actually designed to eventually ware out across the contact points.  Any type of pitting or
though, so be careful if someone tells you they need to be replaced more often than that.

called a two pole contactor.  This means that there are two sets of contact points and when the thermostat is NOT
calling for heating or cooling, no electricity at all is sent to the unit.

This would seem to make sense but on a heat pump it is important that one leg of voltage always be sent to the
compressor's sump heater to keep the oil warm in winter.

The picture above shows a single pole contactor for a heat pump.  You will notice the red wire on the right side goes to
a screw terminal.  If you keep moving to the left you will see the contacts.  These consist of the oval piece of metal with
the rectangular piece of plastic in the center.  This floats on a spring until the thermostat sends 24 volts to the contactor
and pulls the contact in allowing voltage to travel across to the terminal screw on the left.

On a two pole contactor, this set up is on both sides of the contactor.  The one in the picture just has one set of
contacts.  If you look to the right again at the blue wire you will notice as you move across the contactor from left to right
it does not go through a set of contacts.  It provides constant electricity to the unit which is vital in the winter so your
compressor will not be damaged.

Most companies will replace this contactor with a two pole so they don't have to carry two kinds on the truck.  You can
do this but a jumper wire must be installed across one side of the contactor to ensure the sump heater remains
energized.  YOU DO NOT WANT to damage your compressor... that IS an expensive repair!
Phone: (757) 506-6488
This is a sealed contactor.  
Notice how you cannot see the
contacts.  Bugs and dirt cannot
get into the contact area and
cause trouble.
Full Load Amps-Inductive 30
Full Load Amps-Resistive 40
HP @ 1 Phase - 120 Volts 2
HP @ 1 Phase - 230 Volts 5
Number of Poles 2
Package Quantity 1
Type Definite Purpose Contactor
Unit Depth 2.22 inches
Unit Height 3.29 inches
Unit Width 2.16 inches
This contactor replaces most contactors in
residential units