Not every air conditioning problem needs a technician. A fair number of the
no-cooling calls we take in a Houston summer turn out to be one of four things a
homeowner can check in ten minutes, and knowing which is which saves you a service
fee and, in August, a wait.
Work through these before you call. If none of them is the answer, the problem
is beyond a homeowner fix and it is worth having someone look at it properly.
1. The filter
A clogged filter is the single most common cause of poor cooling, and in this
climate filters load faster than the box says. Restricted airflow makes the system
work harder, cool less, and eventually freeze the evaporator coil — at which point
you get warm air out of the vents and a puddle near the air handler.
Pull the filter and hold it up to a light. If you cannot see light through it,
change it. If the system has been running that way for weeks, give it a few hours
after the change before judging whether cooling has recovered; a frozen coil needs
time to thaw.
2. The thermostat
Check that it is set to cool and not fan only, and that the
temperature is actually below the room reading. It sounds obvious, and it is
regularly the answer — particularly after a power cut, which can return some
thermostats to a default schedule nobody chose.
If it is a battery model and the display is dim or blank, replace the batteries
before anything else.
3. The breaker and the disconnect
An air conditioner usually has two power supplies: a breaker in the panel and a
disconnect box outside near the condenser. Look at both. A breaker that has tripped
once can be reset, and if it holds, it may simply have been a surge.
If it trips again, stop. A repeatedly tripping breaker is telling you something
is drawing more current than it should, and resetting it over and over risks the
compressor and the wiring. That is a call, not a fix.
4. The condensate drain
This is the one most people have never heard of and the one that causes the most
damage. Your system pulls a great deal of water out of Houston air and sends it
down a drain line. When that line blocks with algae, the safety switch shuts the
system off — which is the system protecting your ceiling rather than a fault.
Look for standing water in the drain pan or a slow drip that has stopped. If the
pan is full, the drain is blocked. Clearing it is sometimes a shop-vac job at the
outside end of the line, and sometimes not.
When it is not one of these four
If the filter is clean, the thermostat is set correctly, the breaker holds and
the drain is clear, then the likely candidates are a failed capacitor, a
refrigerant leak, a contactor that is not pulling in, or a compressor that is not
starting. None of those is a homeowner repair, and two of them are made worse by
running the system while you wait.
What you want at that point is someone who measures rather than guesses — static
pressure, temperature split, refrigerant pressures against the manufacturer’s chart
for the day’s conditions — and who tells you what needs doing and what does not.
That is what our
air conditioning
contractor page sets out, including how we approach the repair-or-replace
decision on an older system.
If the system is more than a decade old and this is not the first failure of the
season, it is worth having that conversation now rather than in the middle of the
next heat wave.
We work across Houston and the southwest suburbs, including Sugar Land, Katy,
Missouri City, Stafford, Richmond and Rosenberg. Read more about
our HVAC repair service, or
get in touch if you have worked through
the list and the house is still warm.