I have an outside A/C unit that does not do anything, I replaced the thermostat over the winter, the heat kicks on with the furnace no problem, but at the thermostat you hear the click when setting the temperature below room temperature, but nothing happens out at the outside unit. I checked the ohms at the capacitor, they went from a high # to virtually 0, could it be the run/start capacitor?

So Help me get this fixed...

Do you have 24 volts and 220 volts at the contactor? Is the capasitor swollen at the top?

I did not check the voltage there, but it had the voltage there before, so I would assume nothing has changed. There seems to be NO swelling with the Capacitor.

Is the contactor pulled in? If not try pushing it with a screw driver and see if it comes on.


http://rocky.digikey.com/weblib/Potter%20Brumfield/Web%20Photo/P25P42D22P1-24.jpg

Press the botton in the middle.

When you replaced the t-stat did you put a jumper from rc to rc?

I rewired it the same way it was wired, they are both electronic T-stats, nothing changed at all. I hear the click in the T-Stat when putting the temp below room temp.

I will have to test the Contactor, I was not aware of this being an issue and I will check the voltage at the terminals, which ones should I test across?

Well usually the main 220 power comes to the bottom 2 termanals, ck for 220 volts at the bottom 2 and the top two. Then the 24 volts should be two small blue wires on the left and 1 on the right side of the contactor. Chack for 24 vollts between them two.

Does your indoor blower run when the t-stat clicks for ac?

No inside blower doesn't do anything for A/C, it works great for Furnace and the heat.

OK then is sounds like it is a t-stat problem then. If neither the indoor or out work.

Take the stat off the wall and jumper between red and yellow and see if anything comes on.

Also look for that jumper between rh and rc. Make sure it is there.

OK, I guess I am very confused as it works to kick the furnace (blower) on, it also "clicks" when the unit is on cool and you set the temp below room temp?

One thing I am confused on, again I rewired it the same way (5 wire) it was before, of course it had no issues other than the heat wasn't working before. There was no "jumper" wire then, so why would I need one now?

May be you old t-stst did not have a rh and a rc just a r. rh gives the heat power and rc gives the ac power. If you have the red on rh only the ac will not recive any power inless it is jumpered to rh. Same as if you only hook the red wire to rc the furnace would not get power.

I was able to check the contactor and the button was not pushed in, however when I pushed it in the outside fan came on, so it has power to the unit, I could not get any readings at the Capacitor, so what do you think?

Did you check to see if you had a wire on rc?

No I was not able to go inside the home at the time, I will do that, however my question would come as to how there would be power to the fan/compressor and when I hit the contactor it fires the fan up. Wouldn't that indicate there is power to the system at some point, but the capacitor is not kicking the contactor on? Or maybe the contactor isn't working as it didn't push in when the signal is sent from the inside unit?

Just asking

The contactor is supposed to be pulled in by the t-stat. by you pressing it in shows that there is 220 volts going to the unit, but not 24 volts. So the problem would be at the t-stst or the indoor unit not sending the power.

OK Thanks for the information, I will check the Jumper wire and if it isn't there will replace it with one. Afterwhich I will test the system and see if it will in fact kick on or not.

BTW, thanks for all the help and explanation.

No probem, if it has a jumper wire. Anouther thing you can do while you have the t-stat off the wall is to jump from r to y and see if it runs this will tell you if it is still a t-stat problem or if it is some where else.

Ok, I did go to see if it had the jumper, it did not, so I placed a jumper in, still nothing out at the unit. I can push the contactor in and the fan outside will kick on. I forgot to check about the R-Y and seeing if the unit would run, what other T-stat checks can be done. There is resistance at the capacitor and voltage at the contactor.

ok then is sounds like it is a t-stat problem then. if neither the indoor or out work.

I totally agree here. I just want to add that the jumper he is talking about is from Rh to Rc, a typo I'm sure. This is very common with stat replacements.

As stated in above posts, your problem is not at the outdoor unit. Forget about the outdoor unit for now. The problem occurred when new stat was installed. Double check to make sure there is a jumper between rh, and rc. Then if this doesn't work, do the rh to why jump and see if indoor blower comes on. This is most important at this point. Don't worry about the outdoor unit for now. Do your test and see if indoor blower comes on, if it doesn't come on, then neither will the outdoor unit. IF jumping rh to why at stat doesn't work, then go to the inside unit and jump are to why at the control board on furnace, let us know what you find and we will help you get this thing licked. Good luck and hope to hear from you soon.

Why do so many D.I.Y. thermostat replacements go wrong? :confused:

Ok sounds good, I will check, the problem I have it that the furnace worked for 4 months since I changed the T-Stat. However once I put the jumper wire in, the furnace didn't kick on either?

Does anything work on the furnace now? May have blown a 3amp fuse. Its just hard sometimes for us to help fix a problem when we can't see the things you are doing. Just do one thing at a time and let us know. Start by jumping r to y at furnace control board. Also let us know if blower on furnace kicks on when thermostat is set to fan on.

Did you turn the power off while installing the jumper??

I did NOT turn the power off as it was simply adding a jumper, did I possibly fry the circuit board or something to that T-Stat? Because the Furnace had worked before.

Check the contol board for a small 3 amp car type fuse

OK, where might that control board be located? On or near the furnace?

Bottom door of the furnace.

OK, Replaced T-Stat, looked for the fuse on the Circuit board and could not find one? The unit is a Trane TUE060A936K3.

HELP!

Nothing kicks on, you can hear the T-Stat Click to activate either one and nothing.

Before installing the jumper wire the Furnace worked, after nothing works (did not shut power off when installing jumper wire, of course there were sparks) all circuits in main circuit breaker are on and good.

If the power supply to the furnace has been on for some time, the transformer should feel warm to the touch. Turn power off before checking. If it's cool, uh-oh... something is wired wrong or shorted and burned the transformer.

Ok, and this transformer you speak of is there on the circuit board? I take it this particular circuit board does not consist of the "automotive" style fuse that can easily be replaced, it will most likely need a new Control Board, right?

Manual:
http://www.trane.com/webcache/un/split%20system%20air%20conditioners%20(ss)/product/22-1624-05%20en_01011999.pdf

OK, with this manual you have provided, what am I looking for in these? I mean it has schematics and such, but really isn't leading me into the whole solution realm.

If you're not getting it yet, it may be time to call in a pro.

Yes it could be, however I have only done what has been suggested. I installed the JUmper wire, when I did that I failed to shut the power off, so I might have either fried the Control board since I can't seem to locate a "quick" change fuse, I am supposing I will need to change the whole control board?

Well, maybe now you are getting it. "Supposing" as opposed to effective troubleshooting usually results in unnecessary parts changing to solve a problem. It's not likely that you "fried a board", but on-site diagnostics will almost always be more effective than internet help. Did you try my earlier suggestion (checking the transformer for warmth)?

No I was not able to go inside the home at the time, I will do that, however my question would come as to how there would be power to the fan/compressor and when I hit the contactor it fires the fan up. Wouldn't that indicate there is power to the system at some point, but the capacitor is not kicking the contactor on? Or maybe the contactor isn't working as it didn't push in when the signal is sent from the inside unit?

Just asking

Is this not your home your working on? If not just think about the liability if something goes wrong. Its time to call some one who knows.

Luckily this is my rental home, so I have a little time to work the problem. (IT hasn't gotten too warm yet)

No I have not been able to test or touch the Transformer, my original question to that was "where is that transformer?" is that one of the black boxes on the circuit board. There is a picture posted above in the thread.

The transformer is not hooked to the control board.

http://www.mobilehomerepair.com/media/img/nordyne/621299.jpg

Josh,

Ok, so will this be mounted on the furnace somewhere? Also, from the picture I posted earlier, you can see that I don't have that quick fuse on the control board (or if there is one, I can't find it)

Thanks for all your help.

If it is not on the board itself then it may be inline on on the wire coming from the transformer to the board. Usually the transformer is mounted very close to the control board. It may even have a reset on it.

Ok, and if the transformer is not warm and doesn't have a reset on it, then it will most likely need replaced?

What if it is warm then where do we go?

If it blew it will no longer be warm. Inless it just blew out. What you will have to do is locate it. And remove the 2 screws that hold it and just smell it for a electricial burn smell. That is the only way to tell with out a volt meter, same with the control board if you turn it over you can look for a burn mark on the diodes. Make sure to turn the power off before doing so.

Ok sounds pretty easy, I do have a volt meter, what do I need to check with that?

I am trying to recall on the furnace, but it does have a switch, probably the main switch on the side of the unit, then I am trying to recall if it had any "transformers" in sight.

Thanks for all your help.

There are 2 power wire to the transformer that should have 120 volts then the 2 other lead are the low voltage that go to the contol board you should get 28 volts from them.

Now when I was there last I did check for voltage going into the control board and there was nothing, of course I didn't check near the Transformer, so once I locate it I will do so, hopefully I will get up there this afternoon.

OK, checked at the transformer, nothing, no voltage whatsoever. (I made sure I pushed the button in and checked)

No 110 volts or 28 volts? Or just no low voltage?

There was nothing at the transformer. Looking at the wiring it appears that the wires go from the furnace and the A/C unit to the control board, from the control board of course there are the wires that go to the Transformer, the Red,Blue, Black and White, I checked the voltage there was nothing.

I can't recall at this moment whether I depressed the switch or not, I am most certain I did, there has to be power getting there at least on the 110 V side. If the switch isn't depressed it will not allow any voltage through I assume.

Correct if you do not press the safety door switch you will get nothing.

OK I think we are almost there. I went back to the unit last night and tested the voltage at the Transformer. I had 120V on the line coming in and nothing on the line going out, I have ordered the new transformer, will pick up later today and should have it installed this evening.

Sounds like this is your probem if you have no power coming out.

Yes, I will get it replaced and hopefully late tonight or tomorrow I will have good news on the furnace and A/C units functioning properly.

Ok replaced the Transformer, it warms up, has 120 + V coming in, but nothing coming out still? I hear the T-Stat kick in to switch the A/C or Furnace on, but at the control board there is nothing. Again there is no output at the Transformer.

If it's a universal transformer 115v,208v or 230v do you have the line voltage right. You can wire it up using the wrong wires and it will not produce 24v. If you have 4 wires on the line voltage side check them.

The transformer showed as an OEM replacement 120v - 24v. I think I reversed the wires at first, but then changed it to the correct and still nothing.

You have a transformer for a 115v system(gas furnace), and you don't have a electric fan coil that needs 230v to work right. If all is true and you have a 115v to the two wires going to the transformer and you don't have 24v at the two that are leaving it you blew another transformer.

Yep that is what I figured, so what could cause that? The wiring at the T-Stat was a 5 wire configuration, would adding the/a jumper wire cause this or would it have happened due to putting the wires on the Transformer incorrectly or both?

Ok,

Here is the newest discovery... The new part # for the Transformer has the wires or at least the connections reversed. There are male end connectors on the Transformer for V-in(115v) and V-out(24v), on the old Transformer the 115 went to the large male connector while the 24 went to the small. On the circuit board the connector (which can be seen in the picture on page 4) shows the wires coming out, my NEWEST question is do those wires just pull out of that connector? If so I am going to reroute the wires to the appropriate locations, (small end to the right one) noting the schematic on the door and such.

Any issues with this idea and will they simply pull straight out of that connector with a pair of needle-nose pliers? A/C guy wants $120 to "rewire" if that is all it needs?