My AC is not working. I tried switching the breaker and tried
replacing the fuses on the outside box. The key to all of this is that
the thermostat refuses to even turn on. It is digital, not batter
powered, and it does not have a read out. Does this mean a simple
power problem somewhere along the way?

Is there an inside unit and an outside unit? There usually is a separate
plug in for systems where the inside unit is. This would power the
thermostat.

May want to check that the inside unit is plugged in and that the outlet is
working. Plug a lamp into the outlet to test.

Other than that, call for service...

"Samuel" wrote in message
My AC is not working. I tried switching the breaker and tried
replacing the fuses on the outside box. The key to all of this is that
the thermostat refuses to even turn on. It is digital, not batter
powered, and it does not have a read out. Does this mean a simple
power problem somewhere along the way?

I tried fooling with the outside unit some more. The helpful guys down
at Ace hardware suggested I reset the compressor and see if that helps.
I am having trouble finding the compressor reset button from the view
I have now, but I am taking a break for a bit (I live in AZ and it's
crazy hot outside, espescially right in the sun) and will remove
another panel of the unit so I can see what's going on.

My next thought is to go buy a ladder and go into the attic and check
the power. But I don't know what would make it stop working suddenly
if it is merely a power problem. I'm betting on the compressor, but
don't know why the thermostat would not have power, then.

If this reset doesn't work, I'm going to see if I can replace the
thermostat for cheap. Good luck, right?

Could it be a bad breaker then? I tried replacing the fuses, which did
not work. I checked the old fuses at ACE when i returned the new ones
and they said they are working fine. The only easy-to-fix thing I can
imagine is the breaker. But when the AC first shut down, we checked
the breaker and the AC breaker was not tripped. We reset it anyway,
and that did nothing. So we did all these things. I'm out of ideas,
but hate to have to wait two or three days so an AC guy out here can
charge me a couple of hundred - the peak season rate, of course - to
fix what seems to be a simple problem.

On 10 May 2006 10:09:15 -0700, "Samuel"
wrote:

My AC is not working. I tried switching the breaker and tried
replacing the fuses on the outside box. The key to all of this is that
the thermostat refuses to even turn on. It is digital, not batter
powered, and it does not have a read out. Does this mean a simple
power problem somewhere along the way?

It does indicate a power problem but it could be any one of several
things. even a bad Tstat.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

Samuel wrote:
The key to all of this is that
the thermostat refuses to even turn on. It is digital, not batter
powered, and it does not have a read out.

If the the thermostat was working, and now it does not have
a display, that seems to indicate that the thermostat is not
getting power.

As others have indicated, the thermostat usually runs off of
24 volts AC, which usually comes from a line voltage-to-24v
transformer in the air conditioning unit.

If the thermostat has power coming in, but doesn't
light up, I would suspect the thermostat. If there is no power
to the thermostat, the problem is further upstream.

Could be a broken or bad connection from the transformer
to the thermostat, or a transformer failure.

If you're not comfortable reading schematics, using a volt-
meter, and poking around electricity, it's time to call in a
professional.

Jerry

Samuel wrote:

Could it be a bad breaker then? I tried replacing the fuses, which did
not work. I checked the old fuses at ACE when i returned the new ones
and they said they are working fine. The only easy-to-fix thing I can
imagine is the breaker. But when the AC first shut down, we checked
the breaker and the AC breaker was not tripped. We reset it anyway,
and that did nothing. So we did all these things. I'm out of ideas,
but hate to have to wait two or three days so an AC guy out here can
charge me a couple of hundred - the peak season rate, of course - to
fix what seems to be a simple problem.



Only do what is outlined below, if you are certain you can work around
240- volts safely!
If not find someone that has a lot of experience working o electrical
circuits!
Buy a multitester, "Set it at 250-volts AC" and check for 220 to
240-Volts on the control contactor in the condenser.

If there is 220 to 240-volts AC there, leave the tester set at 250-volts
until you know you are on low voltage then set it to a lower AC voltage.
Then check for 24-volt there and at the furnace. If there is NO
24-volts there, it could be a manual reset cutout open in the 24-volt
circuit open.
Turn the beaker off and on, on the condensing unit too. Some units have
two Transformers, and there and one at the furnace.

Do NOT take any chances, 115-volt circuits can kill you deader than a
hammer! - Darrell

--
Air-Conditioning Trouble Shooting Chart
http://www.udarrell.com/ac-trouble-shooting-chart.html

Samuel wrote:

My AC is not working. I tried switching the breaker and tried
replacing the fuses on the outside box. The key to all of this is that
the thermostat refuses to even turn on. It is digital, not batter
powered, and it does not have a read out. Does this mean a simple
power problem somewhere along the way?

Are you _sure_ it's not battery powered? If so, then it's almost
certainly powered by a 24V transformer somewhere. Find that transformer
and confirm _it_ is getting power, and that it is outputting 24V to
the low voltage circuitry. It is probably on a different circuit from
the AC compressor itself, so will be associated with a different
breaker.

Assuming you have the manual for the thermostat, you might be able
to figure out which wires control the AC and see whether the AC starts
if you short them together. That would clearly point to the thermostat
as the culprit. But don't proceed unless you're sure you've got the
right wires. :-)

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

On 10 May 2006 10:09:15 -0700, "Samuel"
wrote:

My AC is not working. I tried switching the breaker and tried
replacing the fuses on the outside box. The key to all of this is that
the thermostat refuses to even turn on. It is digital, not batter
powered, and it does not have a read out.

It never has a read out? Or it usually has one and doesn't have one
now?

Does this mean a simple
power problem somewhere along the way?

If the latter, maybe. Nothing from ##### down is relevant unles the
problem is the latter.

Do you have a furnace too, in the same unit? Try turning your furnace
on.

As to the AC, try changing the temp that the AC is set for. First
down, then up, then down again. (I would suggest different things if
you seemed to be used to using a meter, etc.)

If you have the manual for the AC or the thermostat, or you search the
archives of this group, it will say what the colors of the wires to
the thermostat are. Out of several, you connect two, and the AC
should go on.

#######
If the AC thermostat depends on power from the AC, I had that 2 months
after I moved in. No AC, no 24 volts. The 24 volt transformer was
built into the end of the controller box (the unit is now 27 years
old. It was 4 years old then.) and they wanted iirc more than 200
dollars for the controller box. At the AC supply store, I asked if
they had just the transformer, and he didn't have one as small as
mine, but he did have one that was bigger. Maybe 20 dollars. But I
don't know if your controller is made like mine, and if it is, you
have to be able to find the transformer, find the output places on the
circuit board, use a meter to verify that the 24 volts isn't there
(while the AC is on, but not a risk if you don't cut into the 110volt
wire that is on the other side of the transformer ),

Stop here. You have to verify that their is 110 to the input of the
transformer and no voltage out. If both of those aren't true, it's
probably not the transformer. I only have one house, and in my
limited experience, that's the only part that you can replace that
might be the problem. But if it's not the problem, replacing it is a
waste of time and money. Get a digital volt-ohmmeter (multimeter)
maybe at Radio Shack. Don't get the once that are especially small.
Get the one that costs between 15 and 20 dollars iirc.


..... then buy a 110volt to 24 volt transformer of sufficent size, turn
off the power, mark all the wires by color and location, remove the
control unit, remove the old transformer, mount the new transformer
somewhere in the AC box, and run two pairs of wires from the new
transfromer to the places where the old transformer was connected. 2
wires with 110 volts and 2 wires that get connected to the circuit
board where the old transformer had its output wires connected. make
sure you don't connect the transformer backwards, that you have the
110 volt side connected to 110 volts.

I used the last one's advice and it totally worked. Replaced the
transformer and it's back on! Thank god, it was getting hot in Tucson
this week. No idea why it did that or what happened, but this house is
something like ten years old and the outside unit was replaced last
summer, but the transformer was our old one, so it's probably something
to do with that.

Thanks everyone -- awesome group!

First, you should post this on alt.hvac, the guys on that group can
give you what you need.

Second, replace the thermostat sounds like exactly the right thing to
do. Be sure to ask for help on color codes for the wiring.

--

Christopher A. Young
You can't shout down a troll.
You have to starve them.
..

"Samuel" wrote in message
oups.com...

If this reset doesn't work, I'm going to see if I can replace the
thermostat for cheap. Good luck, right?

From your several posts, you don't have the skills to troubleshoot
and diagnose. An AC guy may be your only answr. Or go to Walmart and
buy a couple window units.

--

Christopher A. Young
You can't shout down a troll.
You have to starve them.
..

"Samuel" wrote in message
oups.com...
Could it be a bad breaker then? I tried replacing the fuses, which
did
not work. I checked the old fuses at ACE when i returned the new ones
and they said they are working fine. The only easy-to-fix thing I can
imagine is the breaker. But when the AC first shut down, we checked
the breaker and the AC breaker was not tripped. We reset it anyway,
and that did nothing. So we did all these things. I'm out of ideas,
but hate to have to wait two or three days so an AC guy out here can
charge me a couple of hundred - the peak season rate, of course - to
fix what seems to be a simple problem.

Stormin Mormon wrote:
From your several posts, you don't have the skills to troubleshoot
and diagnose. An AC guy may be your only answr. Or go to Walmart and
buy a couple window units.

================================================== ============
Samuel" wrote in message
oups.com...
Could it be a bad breaker then? I tried replacing the fuses, which
did
not work. I checked the old fuses at ACE when i returned the new ones
and they said they are working fine. The only easy-to-fix thing I can
imagine is the breaker. But when the AC first shut down, we checked
the breaker and the AC breaker was not tripped. We reset it anyway,
and that did nothing. So we did all these things. I'm out of ideas,
but hate to have to wait two or three days so an AC guy out here can
charge me a couple of hundred - the peak season rate, of course - to
fix what seems to be a simple problem.

================================================== ============

Strange electrical system with BOTH fuses and breakers!!!!

Contactor in compressor could be bad. In mine, the original installer
had left a pair of of pliers inside the contactor compartment. 10 years
later, something bumped the cabinet and the pliers fell onto the contacts.

Lots of reasons why no cold air. If fan doesn't start and compressor
doesn't start, its 24vac for thermostat and contactor coil, or a bad
thermostat.

If compressor runs and fan doesn't, then bad thermostat. If fan runs
but compressor doesn't, less clear whether that is thermostat or
something outside in the compressor case.

Robert Gammon wrote:



Strange electrical system with BOTH fuses and breakers!!!!


Nope, not so strange. In my experience, there is usually a
manual disconnect near the AC unit with cartridge
fuses inside.

Jerry

wrote:
Robert Gammon wrote:



Strange electrical system with BOTH fuses and breakers!!!!



Nope, not so strange. In my experience, there is usually a
manual disconnect near the AC unit with cartridge
fuses inside.

Jerry


Here we have manual disconnect only, no fuses