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Matthew
Matthew, HVAC Technician
Category: HVAC
Satisfied Customers: 2014
Experience:  14 years experience in the HVAC field of service, installation, Manual J & D calculations
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I have a Trane XL14i ac it is not coming on outside. We just

Resolved Question:

I have a Trane XL14i ac it is not coming on outside. We just bought the house 3 weeks ago. I do not know how old it is or when it was last serviced. This was the first day it was hot enough to turn on the air and of course it's not working. The unit in the attic is running and warm air is coming out of the ducts. Nothing running outside. I checked breakers. Nothing tripped. I cannot find a reset button on the outside unit.
Submitted: 6 years ago.
Category: HVAC
Expert:  Matthew replied 6 years ago.

Matthew :

Hello, My name is XXXXX XXXXX I will do my best to help you today.

Matthew :

If the outdoor unit isn't coming on with a call for cooling then one of three things is happening.

Matthew :

1. There is no high voltage to the unit

Matthew :

This could be because of a tripped breaker, a bad breaker, a loose high voltage wire, the disconnect switch outside next to the unit is not in

Matthew :

2. There is no low voltage being sent to the unit.

Matthew :

This could be a bad thermostat, a loose thermostat wire, a safety device open like a condensate pump or float switch.

Matthew :

3. The duel capacitor inside the outdoor unit is bad and not starting up the fan motor or the compressor.

Matthew :

In order to determine what it is you need a voltage meter, some experience dealing with voltages, and the ability to take the panels off the outdoor unit, thermostat, and possibly the furnace.

Matthew :

Let me know what you are capable of and we will go from there.

Customer:

Oh boy...Let me grab a meter. Be back in a min

Customer:

I have a volt meter. What do you want me to check first?

Matthew :

take the cover off the outdoor unit and find the contacts. I'll send a picture. At the contacts there will be two wires that hook to one end that come from a disconnect box that hangs on the side of the house. With one test lead on one of these lugs on the bottom of the contact and one test lead on the other lug you should read 240v. See if you do.

Matthew :

Full Size Image

Matthew :

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Matthew :

40 Amp 2 Pole Standard Duty Contactor Used in units ( 3-1/2 Ton up to 5 Ton
Full Size Image

Matthew :

One end is the high voltage coming into the unit from the house the other end is the wires leading to all the parts inside the unit

Matthew :

while you are there checking take notice of the small plunger in the middle. See if it is up and not making contact with the metal below it or if it is down and touching the metal below it.

Customer:

ok, I have 240 at the lugs

Customer:

if what I am looking at is correct the plunger appears to be up

Matthew :

if it is up then that means no low voltage to the unit.

Customer:

actually, after a second look. the plunger may be in the down position. It looks like the whole carraige inside slides up and down. My part resembles the middle pic you sent

Matthew :

right there is a black middle holder with a copper bar through it. When engaged the copper points on this are down touching the metal below

Matthew :

there would be a slight hum when it is down

Customer:

there is a slight hum

Matthew :

your capacitor is bad. Very common service part

Matthew :

here is a picture

Matthew :

Full Size Image

Matthew :

When they are bad most of the time it will be swollen and disfigured.

Matthew :

They can still be bad without being disfigured but most often the top will be bulged up at the very least.

Matthew :

to test the charge on this capacitor you need a setting on your multi meter labeled MFD.

Matthew :

is this unit surrounded closely by bushes, a fence, covered by a porch, or anything like that?

Customer:

pic did not come through. Is the capacitor the silver colored fit in the palm of your hand?

Customer:

yes bushes

Matthew :

Full Size Image

Matthew :

This is a swollen top on one

Matthew :

Full Size Image

Matthew :

that pic come through?

Customer:

got the pics. i will go check it now.

Matthew :

these capacitors will go bad with just time, but the xl14i is a fairly new model so I can't imagine the unit is very old. Heat build up around the unit caused by smothering it with bushes, fences, or other things will cause the life of these capacitors to be cut short. make sure the coil on the outdoor unit doesn't have build up of dirt and pollen you may want to wash it down with a water hose.

Customer:

I don't see any visible signs of swelling or discoloration. Nice shiny and new looking

Matthew :

can you find me the actual model number of the unit it will be a 2TX######

Customer:

2TTX4030B 1000AA

Matthew :

There is a hard start kit on this model it has an orange wire off of it leading to the capacitor. This could be shorted out but this would just prevent the compressor from coming on the condenser fan motor should still come on.

Matthew :

If the contacts are pulled down and there is 240v to the contacts from the house then the only thing that would prevent the condenser fan motor and the compressor from coming on is this capacitor. It may look fine but it has to be it.

Matthew :

you could try unhooking the hard start and see if it works. just unhook the orange, black/blue, and red wire coming off the hard start and then try the system again.

Matthew :

page 2 shows this hard start kit with the relay and other capacitor looking thing

Customer:

I will give it a shot

Customer:

I give up. The hard start and other capacitor looking thing appear to be mounted on the otherside of the service area. The wire are going through the wall in the unit. I can see them through the fins on the back panel. It's dark, I'm aggravated. I will try it in the morning. Then I guess I will go buy a capacitor.

Customer:

Thank you very much for your time and patience

Matthew and other HVAC Specialists are ready to help you

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