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NJScott 05-29-2012 08:08 AM

Inside fan runs...outside unit does not
I checked the fuses in the box outside and they are ok. I found a contactor inside the unit that is not pulled in and when I press it the unit starts running but still co cold air.

Doc Holliday 05-29-2012 08:35 AM

You won't have any cold air unless both the inside fan and the outside condensing unit are running simultaneously.

You wanting to diagnose this yourself? Let me know, I'll walk you through it but you you're going to need a few tools such as a Philips screwdriver, some small wire like thermostat wire or gator clips and a meter.

NJScott 05-29-2012 09:05 AM

have a fluke 77 iv meter and screw driver....sure I could find some wire....might have to buy some clips

Doc Holliday 05-29-2012 09:16 AM

On call for cool the contactor should be pulled in on the condenser. You said it was not. Turn the stat onto cool. If digital stat wait for about a minute or two before following next steps as digital stats have a time delay to the condenser.

Check for 24 volts at the contactor on the low voltage side. Follow the two small thermostat wires into the condenser to where they attach onto each side of the contactor. Check across those two terminsals for voltage. Be careful to not touch the high voltage in the contactor, it hurts!

NJScott 05-29-2012 10:31 AM

Had to go to my day job. Will try this when I get home. Thanks

NJScott 05-29-2012 11:02 AM

And I am no stranger to testing contactors. Believe I can find the coil.
If you have time... Can you send a what next for yes there's 24v and no 24 v?

NJScott 05-29-2012 11:05 AM

Also.... 24 ac or dc

Doc Holliday 05-29-2012 11:33 AM

Just keep asking here, plenty of techs willing to assist.

Checking alternating current, not direct.

If there is 24 volts than that means the control boarrd and stat are sending the signal to the condenser (contactor). Now what you do is test continuity through those two low voltage terminals to see if the coil is open (OL) or not. Power to unit will need to be off and wires removed prior.

If the coil is broken and showing OL then the contactor is bad, it won't ever pull in. But if this were the case and your furnace has a control board most likely the fuse on the control board would blow, thus you'd not have 24 volts to the condenser.

Also, does your condenser have any pressure swiches on it? Google search 'condenser pressure switch' to find what to look for.

Then we'd work our way backwards, checking voltage in the thermostat and finally in on the control board itself.

More to check after that such as if a wire is broken or if a fuse is shot or a transformer burnt up or..

It sounds like a lot but it's really not. Keep asking.

biggles 05-29-2012 12:24 PM

shut the disconnect OFF out at the condenser the 24V comes from the furnace TR...need to read 24Vs right on the contactor coil with the stat calling...if you have it and it isn't pulling in the coil on the contactor might be open.go in shut the cooling signal down...remove the 2 wires tested and ring the coil out audible and or ohms...should be a resistive short with a value.if you see a value might not be enough to pull it in and draw the contact bar in.

NJScott 05-31-2012 07:54 AM

Ok I took a couple vacation days so I am working on the A/C. I turned the thermostat to cool. There is not 24V going to the contactor. There is something in series with the wire to one side of the coil. some kind of time delay. took a picture but don't see how to post. Anyway I checked the other side of coil with both wires to the device and no 24V.

NJScott 05-31-2012 07:59 AM

Ok I think I put a pic in the album.

NJScott 05-31-2012 08:27 AM

ok I kept looking and inside the unit where the fan is I found the item in the album. Wondering if that might be the pressure switch.

Doc Holliday 05-31-2012 09:16 AM

Where's the evaporator coil located? Does it have a drain pan underneath it? Check the drain pan or even the main drain line to see if you have a float safety switch. If there is and there's water in the pan, simply lift the switch up, meaning tilt it backwards so the float goes down.

Let us know.

NJScott 05-31-2012 09:25 AM

Theres a automatic condensate pump attached to the unit in the basement. looks like there is just power going to it and hs a hose to outside to drain

Doc Holliday 05-31-2012 09:27 AM

You need to post the pictures here or at the least give a link. It would help.

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