D> A relative's central air condenser coil froze up completely with ice D>
and stopped working. Had to let it melt before it would work again
. D>
This was in very dry and very hot Phoenix. 115F at the time. They
D>
blamed it on the thermostat being set too low and the unit working
D>
too hard to cool the house down. Is this normal? I would think
D>
the A/C would shut itself off before the coils were allowed to ice
D>
up. Seems to me there is something wrong with the A/C, not that
D> the thermostat was set too low. Low on freon?
It could be that the thermostat was set too low. it could also be a dirty filter, refrigerant charge low or a dirty coil. and there are a few other reasons. it is alway good to have a regular maintenance done on any A/C
system.
Dick
It could just be low Freon, but most likely it is low Freon, coupled with low cooling load.
Low load can be caused by restricted air flow or too low an indoor temperature in the house.
I normally would measure the air flow with a flow hood, also called a capture hood. You should normally have around 400 CFM (Cubic Feet per Minute) per ton. Half of the systems I measure have 200 CFM per ton OR LESS. This will be agarvated by a dirty air filter, Restrictive high efficiency air filter or grilles closed in rooms that you are not using.
Normally, do not turn the thermostat down below 70 degrees.
If you find a dirty air filter or the thermostat turned down too low, these are easy fixes. Replace the filter ot turn the thermostst back up. Otherwise, you need aqualified proffessional. Ask if the contractor has NATE certified trechnicians.
Good Luck.
Stretch