A/C guys......need some help here please.

[Goldeneagle]

I've got an appointment with Walker Air Conditioning tomorrow for a Spring check up. Well this morning I noticed an alarm on the thermostat. The code is 405. This is a Lennox set up. Can this wait until tomorrow?

[Charles]

flashes
then pause
Off
Critical Alert
Code 405
Open circuit
Compressor has
an open circuit
due to power dis-
connection, fuse
is open or other
similar conditions.
1
Outdoor unit power disconnect is open.
2
Unit circuit breaker or fuse(s) is open.
3
Unit contactor has failed to close.
S
Check compressor contactor wiring and
connectors
S
Check for compressor contactor failure
(burned,
pitted or open)
S
Check wiring and connectors between supply
and compressor
S
Check for low pilot voltage at compressor
contactor
coil
4
High pressure switch is open and requires manual
reset.
5
Open circuit in compressor supply wiring or
connections.
6
Unusually long compressor protector reset time
due to extreme ambient temperature.
7
Compressor windings are damaged.
S
Check compressor motor winding resistance

[Goldeneagle]

Thanks Charles, but I have no idea what all that is. I'm a machinist not an A/C guy.

[cwbow]

Check your breakers, in electric panel inside and out by unit.

[Goldeneagle]

Check your breakers, in electric panel inside and out by unit.

Can this wait until I get home this afternoon? I'm at work.

[125Dad]

Sounds like you will not have any cool air when you get home.

Yes I think it could wait. I’m not a A/C guy

[Goldeneagle]

Sounds like you will not have any cool air when you get home.

Yes I think it could wait. I’m not a A/C guy

At least the weather ain't that bad.

[Rat]

1) Outdoor unit power disconnect is open.
Check the disconnect to make sure it is closed, if it is a breaker type push all the way to the off position and then back to the on position.
2) Unit circuit breaker or fuse(s) is open.
Check the breaker for the outdoor unit for a trip or open condition.
3) Unit contactor has failed to close.
Compressor contactor is bad or now low voltage signal to close contactor. Check to insure you have low voltage to the contactor coil, if not troubleshoot contactor, if you do you have a bad contactor.
4) High pressure switch is open and requires manual reset.
If high pressure switch is open you will not have low voltage to the contactor. Reset switch if resettable, hook up manifold, check for high head pressure. If switch is not resettable do the same thing but jump out the high pressure switch.
5) Open circuit in compressor supply wiring or connections.
Check the wiring harness from the capacitor and contactor for a break or short in the wires. Check all connections
6) Unusually long compressor protector reset time due to extreme ambient temperature.
Ambient temperature is not extreme, if equipped with a separate delay on break timer the timer may be bad. Jump out timer and see if compressor starts.
7) Compressor windings are damaged.
Using a multi meter or megaohm meter check for an open winging.


If you don't know what half of this means, just check the breakers and see if that is the problem and let your A/C professional do the rest.

Also, there may be fuses in the disconnect, pull the disconnect to check.

[Goldeneagle]

If you don't know what half of this means, just check the breakers and see if that is the problem and let your A/C professional do the rest.

This is what I'm going to do. I know just enough about electricity to get myself hurt.

[elliscountyhog]

Call my office lady and see if we can bump you up to today. Id be willing to bet we can and if not you let me know and i will put the boss foot down lol. 214-388-0707 Christi is the dispatch.

[Goldeneagle]

Call my office lady and see if we can bump you up to today. Id be willing to bet we can and if not you let me know and i will put the boss foot down lol. 214-388-0707 Christi is the dispatch.

Thanks! I give her a call here in a few.

[bowhntrmatt]

Call my office lady and see if we can bump you up to today. Id be willing to bet we can and if not you let me know and i will put the boss foot down lol. 214-388-0707 Christi is the dispatch.

Now that's service!

[125Dad]

Now that's service!

One I hope I never need. Lol

Heard a lot of good things about him and will be my go to for sure.

[Charles]

Update plz.

[elliscountyhog]

Update plz.

You have the same code on your tstat? In the DFW area? I will be glad to help you out as well