Hello All, I'm new here and have a question that I hope someone can help me with.

My A/C thermostat started acting weird a few days back. I have a simple digital stat, with a greenish-glow backlit screen, with settings for cool, heat, and fan. All of a sudden, the screen went blank, no light, and the A/C of course would not kick in. Initially I thought the stat must have gone bad, and I was going to get a new replacement. Decided to take it off the wall mount and check it out. Removed the green and red wires and put them together, the fan didn't kick on... no power? Tested it with a multi-meter, no power at all from any of the wires. So... it's not going to be a simple stat replacement after all.

The strange thing is, after messing with the wires on the stat, and turning the main A/C breaker on and off, suddenly the stat came back to life. Lighted up and settings displayed, A/C kicked in, and this lasted for a couple hours, before it went dead again. That was late last night. Early this morning, my wife said she saw the stat working. Late morning when I woke up, it was dead again.

From my recent research on this forum, as well as eleswhere on the internet, I suspect it could possibly be the transformer. But I have no idea where that is! Just to make one thing clear, I am not savvy with electrical stuff, I'm pretty handy mechanically, and can follow instructions well though. So, I opened up the air handler in the garage, looked inside at the bunch of wires, there were some similar thin wires as the wall mounted stat's. I tested those with the multi-meter and got positive readings around 18 V.

Now I'm thinking it must be somewhere else... so I opened up the panel in the condenser(?) at the back of the house (the noisy one with the fins and fan). Tested the terminals where the power enters (A & B) and is connected to some device (attached pic below) and got around 110-120V. Tested the other terminals (C & D) which look like where the power gets distributed to those familiar thin wires that I saw on the wall stat. No Power there... so I assume I've found the culprit! Well, being an amateur, I am not sure. And that's why I'm here.

Here are some pics of the panel in the condenser/compressor (sorry, I don't know the correct name for this noisy thing! LOL!). Can someone confirm if this is the transformer, if not, what is it called? There looks like a little contact point, I guess for the timer to kick the thing on/off. Judging from my description, is this the faulty part, and should I attempt to replace it myself since I have come this far?

I am one of the many unfortunate unemployed ones, and would rather do this myself, if I can. If I have to, I don't mind getting someone to do the job, if there are big risks involved.

Thank you all.


http://img39.imageshack.us/img39/4062/ac01.jpg


http://img39.imageshack.us/img39/3492/ac02.jpg


http://img39.imageshack.us/img39/8163/ac03.jpg


http://img39.imageshack.us/img39/9114/acmodellabel.jpg

Sorry, I left this note out... don't see an "Edit" button anywhere, so have to make another post to add:
There's no power at the terminals of those thin wires (bottom right corner of the first pic above) that look similar to (or leading to/from) the thermostat's inside the house.

First before we get into what the wires are and such I want to ask you, does the thermostat have batteries in it and does the LED light show you anything on the thermostat that says "Low Battery"

I see you are on line now so I will post this and wait for an answer.

But one warning, The things on the left side of your pictures are all high voltage and very dangerous. The small wires on the right side down low are the low voltage. The thing that you pointed out and ask what it is is called the contactor, and the two small wires on either side is what powers the contactor to make it contact to make the AC run.

I will wait for you answer.

Great answer from tellu. Yes the part in question is the contactor, not the transformer. My first thought would be a low or dead battery in the thrmostat also.

Sorry for the delay... just got this.

There is NO battery in the thermostat. I checked that first. There is a wire that goes in C - which I assume is for the power?

The thermostat just came back to life, and AC is running now. However, I scanned the vents and the air coming out is only 68 deg... ooops, I hope there isn't something else wrong.

Ken, look in your air handler for a small cube shaped object, the transformer. With power on it should be a little warm to the touch and even hum a little. Typical specs on those are 24VAC output, not 18VAC, but check the label on its side to be sure, if readable, and test its input voltage 110-120VAC and its output with your multimeter by backprobing etc.

A transformer on the edge of acceptable voltage could cause flakiness in your tstat. Here's (http://wiki.xtronics.com/index.php/Thermostat_signals_and_wiring)a link that may help explain the internals of your tstat and standard wiring color codes.

Let us know what you find and we'll take you from there.

Ken, look in your air handler for a small cube shaped object, the transformer. With power on it should be a little warm to the touch and even hum a little. Typical specs on those are 24VAC output, not 18VAC, but check the label on its side to be sure, if readable, and test its input voltage 110-120VAC and its output with your multimeter by backprobing etc.

A transformer on the edge of acceptable voltage could cause flakiness in your tstat. Here's (http://wiki.xtronics.com/index.php/Thermostat_signals_and_wiring)a link that may help explain the internals of your tstat and standard wiring color codes.

Let us know what you find and we'll take you from there.

Thanks dac, I will go look in the air handler again. I'll test with the meter and take some pics as well. I noticed that with the main A/C breaker on or off, the Air Handler makes the humming noise either way. Is this normal?

Thanks dac, I will go look in the air handler again. I'll test with the meter and take some pics as well. I noticed that with the main A/C breaker on or off, the Air Handler makes the humming noise either way. Is this normal?

It is likely you have two breakers, one for the outdoor unit and the other for your air handler. If there is humming from the transformer after you've presumably shut off the power you probably shut off the wrong breaker.

This reads well. Kind of interesting reading.

I'd focus your immediate attention on the following two terminals. R & C.

The next time it fails check R & C at the furnace first and R & C at the thermostat. There should be 25 VAC between these terminals at all times.

Those two terminals should go to the transformer in the air handler. There should be 4 terminals or wires. Two go to 120 VAC and two go to R &C.

Look for any loose connections in any of these wires.

There also may be a 3 A automotive type fuse on the control board. Re-seat that.

You need 24 VAC between R & C for the tstat to have power.

Dac, You are correct! I checked again in the main breaker panel, and there IS a separate breaker for AC and Heater. I assume Heater would control the Air Handler, and AC, the Condenser.

Here are some pics of the Air Handler. 1st pic shows the whole layout, just in case you need to point out any particular parts. 2nd pic shows the terminals I tested with the multi-meter. 1-2, 3-4, 5-6, 7-8 all showed 110V. The small panel on the far right, with those wires similar to the thermostat's, show NO power. I tested both inside and outside rows - Zero V. Is this the wire that leads to the thermostat?

Which one is the transformer? The beige color part directly on the left of the row of thin 24V wires... there is a small "switch" or so it looks like, I tried it but it doesn't seem like it switches anything. Perhaps it's just a release to remove the beige plastic casing? There's a closeup pic of it in the 3rd pic.

Thanks for the help.


http://img196.imageshack.us/img196/5477/airhandler01.jpg

http://img196.imageshack.us/img196/5989/airhandler02.jpg

http://img196.imageshack.us/img196/1158/airhandler03.jpg

This reads well. Kinda interesting reading.

I'd focus your immediate attention on the following two terminals. R & C.

The next time it fails check R & C at the furnace first and R & C at the thermostat. There should be 25 VAC between these terminals at all times.

Those two terminals should go to the transformer in the air handler. There should be 4 terminals or wires. Two go to 120 VAC and two go to R &C.

Look for any loose connections in any of these wires.

There also may be a 3 A automotive type fuse on the control board. Re-seat that.

You need 24 VAC between R & C for the tstat to have power.

Thanks for your input, I didn't see your post until after I posted the pics. Well, I guess I answered your questions. If it helps at all... the tstat and hence, the AC has been coming on and off randomly since last night, probably like 3-4 times. It won't stay for long when it comes on though... maybe for an hour or so.

Which one is the transformer? The beige color part directly on the left of the row of thin 24V wires...there is a small "switch" or so it looks like, I tried it but it doesn't seem like it switches anything. Perhaps it's just a release to remove the beige plastic casing? There's a closeup pic of it in the 3rd pic.


Looks to me like your transformer is just behind the terminal block on the right. It appear to have that switch mounted to it for some reason. I see 24VAC on its label peeking between wires, and has that telltale ridged solid block on the bottom. Hard to see from here but it should be feeding your R and C terminals for hot and common respectively. Now check the 120VAC input to the transformer.

Let us know what you find.

Looks to me like your transformer is just behind the terminal block on the right. It appear to have that switch mounted to it for some reason. I see 24VAC on its label peeking between wires, and has that telltale ridged solid block on the bottom. Hard to see from here but it should be feeding your R and C terminals for hot and common respectively. Now check the 120VAC input to the transformer.

Let us know what you find.

I wanted to do that, check the input to the transformer, but I didn't know which is it, and which terminals for sure. And with the power on and that bunch of live wires, I wanted to make sure first. Is the transformer the block with the label, right behind the beige plastic casing? Or is the beige casing part of the transformer itself?

It's kind of tight to get behind there to the terminals on the transformer without touching any of the wires in front... I'll try.

Is the transformer the block with the label, right behind the beige plastic casing? Or is the beige casing part of the transformer itself?

It's kinda tight to get behind there to the terminals on the transformer without touching any of the wires in front....I'll try.

Minimally the transformer is the block with the label. The beige casing might be part of it but it is hard to tell from here. On that block part look for two 120VAC wires going into that block part and two wires emerging from it. There might even be another label on the other side showing input and output, or if you read the label it might tell.

Regardless that's our puppy and you need to verify its working. If worried about all those wires then carefully place your probes on the connectors, pulling back any connectors to expose, or backproble them, or whatever you have to make a connection. Then power on and see. I agree maybe probing around that area while hot might be dangerous since I see 220VAC wires nearby.

Alternatively you could pull the whole transformer out and could bench test it with an extension cord. You seem to be handy enough. Just label everything or take good pics to remember how to rewire.

Ok, here are some closeup pics. I can't seem to find terminals to test. As described in the pics, the wires go into the box itself. Can I test on that part on the top of the transformer? I've also attached a closeup of the label.
I'll wait for advice...

http://img199.imageshack.us/img199/4345/airhandler05.jpg

http://img199.imageshack.us/img199/6180/airhandler06.jpg

Here's some New Discoveries! I traced the wires and A1 and A2 looks like they came from the main input (120V), and they showed 120V on the meter. B1 and B2 seems to lead down to the compartment below (check the earlier pics of larger view angle). That leaves C1 and C2 which seem to lead into the transformer (beige box). Both B's and C's pairs showed 0V on the meter.

I opened up the beige box, and the wires are soldered on. I didn't test those terminals as there's no output anyway on C1 and C2.

So... have I found it yet?? What is that part called? It's a transparent casing, if you need to have a closeup shot, I can go get one.

http://img31.imageshack.us/img31/3632/airhandler07.jpg

..... B1 and B2 seems to lead down to the compartment below (check the earlier pics of larger view angle).....

Sorry guys, I forgot the overall view pic. Here it is:


http://img31.imageshack.us/img31/5477/airhandler01.jpg

On the right picture, you will see this symbol: http://images4.wikia.nocookie.net/howto/en/images/thumb/9/9d/Transformer_electric_symbol.svg/750px-Transformer_electric_symbol.svg.png

That's the symbol for a transfomer. Two of the terminals should be labeled R and C.

The thing that you last pointed too is an enclosed relay.
It does the same function as the contator, except you can't see the contacts.

The thing that's shaped like a "S" is the fuse. It's likely about 3 A and on the low voltage side.

You can post directly to this forum using "Go Advanced/Manage attachements". If you need to resize the images, you can use the free program IrfanView - Official Homepage - one of the most popular viewers worldwide (http://www.irfanview.com)

The transformer may be the obscured object with the white label on the far right of your picture. The Red wire-nutted wire may be going to a fuseholder. I just can't tell with the resolution of the pictures.

On the right picture, you will see this symbol: http://images4.wikia.nocookie.net/howto/en/images/thumb/9/9d/Transformer_electric_symbol.svg/750px-Transformer_electric_symbol.svg.png

That's the symbol for a transfomer. Two of the terminals should be labeled R and C.Thanks, that's good info. I'll look for that symbol to confirm.


The thing that you last pointed too is an enclosed relay.
It does the same function as the contator, except you can't see the contacts.So which means it's normal that there is no power at those B1-B2 and C1-C2 terminals? If the contacts are not on, then there's no power. Is this correct?


The thing that's shaped like a "S" is the fuse. It's likely about 3 A and on the low voltage side.I am lost here, which "S" shaped thing are you referring to?

Here are some pics of the Air Handler. 1st pic shows the whole layout, just in case you need to point out any particular parts. 2nd pic shows the terminals I tested with the multi-meter. 1-2, 3-4, 5-6, 7-8 all showed 110V. The small panel on the far right, with those wires similar to the thermostat's, show NO power. I tested both inside and outside rows - Zero V. Is this the wire that leads to the thermostat?

Which one is the transformer? The beige color part directly on the left of the row of thin 24V wires... there is a small "switch" or so it looks like, I tried it but it doesn't seem like it switches anything. Perhaps it's just a release to remove the beige plastic casing? There's a closeup pic of it in the 3rd pic.

Thanks for the help.


http://img196.imageshack.us/img196/5477/airhandler01.jpg

http://img196.imageshack.us/img196/5989/airhandler02.jpg

http://img196.imageshack.us/img196/1158/airhandler03.jpg

OOOPS! I accidentally made a repost somehow. Can a moderator please remove the above post to avoid confusion?

Sorry, and Thanks!

This thing is a fuse:

http://www.geocities.com/SiliconValley/2072/fuse.gif

This is a DPDT relay. http://www.techitoutuk.com/knowledge/electronics/symbols/relaydpdt.gif The object you labeled.

Who knows what it's function is, but two terminals, like the ones nearest to RL1 in the picture are the coil. When you apply power to the coil, the common contacts move from the unpowered state (Normally closed) to the powered state (Normally open).

Right now, that device is out of the picture.

You need to concentrate on locating the thermostat wires and following particularly the red one.

Right now, that device is out of the picture.

You need to concentrate on locating the thermostat wires and following particularly the red one.

So, the condenser is out.
Now you are saying the Relay is out.
You think there is something wrong with the wire running from the transformer to the thermostat?
What about the transformer? How should I test that now, without being able to activate the Relay/contacts?

The thing you labeled as a "switch "can be either a switch, fuseholder or breaker. I think it's one of the latter two.

Now that I can clearly see the laminations (stacked pieces of grey/black metal), the white section is attached to the transformer. Because your "switch" is enclosed in the plastic case, it is likely on the primary side of the transformer. This isn't guaranteed.

Note, it has markings like 24 VAC and probably sec. or secondary. And 120 VAC pri. Or primary.

Look at how mechanically sound, the tin read and the thin blue connections are.

There is green, brown and black wrapped around the thermostat brown jacket. Look at that cable. Follow the red and blue wires. Remove the wirenut, but not the connection to the red wire. Measure between the red and blue in that cable.

Green is normally used for the fan, but it seems unconnected. I'm assuming blue goes to the C wire of the thermostat.

Look at how mechanically sound, the tin read and the thin blue connections are.

There is green, brown and black wrapped around the thermostat brown jacket. Look at that cable. Follow the red and blue wires. Remove the wirenut, but not the connection to the red wire. Measure between the red and blue in that cable.

Green is normally used for the fan, but it seems unconnected. I'm assuming blue goes to the C wire of the thermostat.

I looked at the wires, they all look good, and secured. However, I can't run it's length to the wall thermostat, it's behind walls! When I test them on the meter, there is no power to any of the 24V wires.

Yes, Blue is on C at the thermostat end. NO power at that end either. I also did connect Red and Green, no response to fan.

Hang on... I opened the beige box in the transformer and took some pics, looks like a fuse. BRB...

Here are pics of that beige plastic cover removed from the transformer. It looks like a fuse, I can't open that black casing up, didn't want to try too hard and break the solder on those wires. I did a connectivity test on the meter on F1 and F2 and it was positive, needle went all the way to the right of the scale. (Sorry, not sure how to read the units for this test, told you I'm an amateur! :D). Anyway, so does that mean the fuse is good?


http://img268.imageshack.us/img268/7241/transformerfuse01.jpg

http://img268.imageshack.us/img268/2302/transformerfuse02.jpg

http://img268.imageshack.us/img268/4602/transformerfuse03.jpg

Yep, circuit breaker: http://www.onlinecomponents.com/productfiles/mf-PB/w28.pdf

The 32 V and the lines mean 32 VDC so it's on the low voltage side.

Measure the voltage across the terminals F1 and F2?

Yep, circuit breaker: http://www.onlinecomponents.com/productfiles/mf-PB/w28.pdf

The 32 V and the lines mean 32 VDC so it's on the low voltage side.

So, is this circuit breaker good and can be put out of the picture here? Did I test it correctly to determine that it's good, if not, how should I test it?

Can I assume that the problem lies somewhere between this circuit breaker and the row of 24V terminals R. W. G. C ?

OK. The red coil of the thick wire should be the low voltage winding. If you can find the two ends, you should have 24 VAC there at all times.

That should be white braid to blue. (24 VAC)

Now look at Blue to white braid + CB + Yellow.
... (C)... (#1)... (#2)

What is C to #1?
What is C to #2

What is the voltage across F1 and F2?

Circuit breaker may still be in the picture, may not. The above tests will help.

Measure the voltage across the terminals F1 and F2?

No I did not, when I had that opened up, I didn't turn on the power.
I just did the connectivity test to see if the fuse was good.
Should I? I can do it if it will prove something to help with the troubleshoot.

Yep, do these with the power on:

Refer to post #32.

What is voltage from C to #1?
What is voltage from C to #2

What is the voltage across F1 and F2?

OK. The red coil of the thick wire should be the low voltage winding. If you can find the two ends, you should have 24 VAC there at all times.

That should be white braid to blue. (24 VAC)

Now look at Blue to white braid + CB + Yellow.
.....................(C)..............(#1)........ ..........(#2)

What is C to #1?
What is C to #2

What is the voltage across F1 and F2?

Circuit breaker may still be in the picture, may not. The above tests will help.

Pardon my dumbness... I'm trying to understand your instructions. I'm completely lost.

What do you mean by "red coil of the thick wire"?
What is "white braid to blue"
What is "Blue to white braid + CB + Yellow"
What is "C to #1"
What is "C to #2"

Here is the post:

OK. The red coil of the thick wire should be the low voltage winding. If you can find the two ends, you should have 24 VAC there at all times.

That should be white braid to blue. (24 VAC) I can see these wires with the coil in the middle

This was my way of drawing a circuit. There is a blue that connects to a red coil and then a white braided wire and then to a circuit breaker and then to a yellow wire. The terminals are paths along it's way

Now look at Blue to white braid + CB + Yellow.
... (C)... (#1).. . (#2)

What is voltage fromC to #1?
What is the voltage fromC to #2

I added the italics.

Point C is the blue wire. Point #1 is the white braid and point #2 is the yellow wire.

Circuit goes like Blue (C) to transformer to a (#1) white braded wire to a circuit breaker to a (#3) yellow wire.

Ok, I think I got you now. The red coil is the Actual Coil (literally) inside the opened white fuse cover, right? So you want me to measure across that short braided white wire, blue wire, yellow wire, etc... right?
Which are you referring to as #1 and #2?

I'm going out to do what I understand right now, and will be back with some numbers.

Here you go:

Blue - Braided White - 26V
Blue - Yellow - 26V
Yellow - Braided White - Nothing

I also tested the row of R. W. G. C terminals...
R-C, R-G, R-W... they all showed the same 26V

Here you go:

Blue - Braided White - 26V
Blue - Yellow - 26V
Yellow - Braided White - Nothing

I also tested the row of R. W. G. C terminals...
R-C, R-G, R-W....they all showed the same 26V

Refer to pics below for a clearer description. Hope I understood you correctly, KeepItSimpleStupid. So, are we there yet? What's the verdict? Wife wants me to call someone in tomorrow, but I've come this far... really don't want to give up at this point. The pressure is on, as Saturday is the last work day, won't be able to get any parts or anyone in on Sunday. And it's getting uncomfortably warm in the house!

http://img194.imageshack.us/img194/7237/transformerfusevac01.jpg

http://img194.imageshack.us/img194/5642/transformerfusevac02.jpg

http://img194.imageshack.us/img194/802/transformerfusevac03.jpg

Do you get power on both lines after you reset the trip out switch?

do you get power on both lines after you reset the trip out switch?

If you are talking about that little reset switch on the fuse, I did try pushing that a couple of times, then tested white-yellow again... No reading.

Question: That row of terminals, R,W1,G,C on the far right inside the Air Handler... if there is power on those terminals, shouldn't there be power leading to the thermostat? Does that wire lead to the thermostat?

When I tested those terminals last night, and saw power on them, I immediately went to the wall thermostat, removed the stat cover and tested the wires from the wall. No power there.

If you have power on r you should have power to the stat. that reset is supposed to click back into place if it is triped, also it may have a little with mark or red showing it is out.

if you have power on r you should have power to the stat. that reset is suposed to click back into place if it is triped, aslo it may have a little with mark or red showing it is out.
Questions:

Does that wire from the air handler (R,W,G,C) lead directly to the thermostat?

If Yes, and If there Is power at R,W,G,C and NO power at thermostat, does that mean there's a problem somewhere along the wire behind the walls??

You should have two wires hooked to the board at the air handler. 1 set to the ac unit, and 1 set to the t-stat. and yes it should go directly from the board to the stat. you have power from r to c at the board now? But not at the stat?

you should have two wires hooked to the board at the air handler. 1 set to the ac unit, and 1 set to the t-stat. and yes it should go driectly from the board to the stat. you have power from r to c at the board now? but not at the stat?

That is correct. Power at air handler side, no power at wall for thermostat.
Check my pics for clarity.

Do you think I should try putting in a new tstat?

You have 24 VAC and the transformer is good and so is the circuit breaker in your tests.

I'm looking at the pic in post #39. It appears that you have a 3 stage heat and cool of some sort.

There is something fishy with the three reds twisted together and the black wire connected to terminal R. That other thermostat wire going to the outside unit seems connected way wrong.

On the strip:

Jumping R to G should make the fan come on.
Jumping R to W1 should make the heat come on.
W2 and W3 are not connected and this is 2nd and third stage heat.

R and C should have 24 VAC on them. They do, so the tstst should light up

R is either not going to the tstat? It's also black and not red. This raises some real wiring flags.

1. Wrong thermostat - not 3 stage heat
2. The AC contactor coil being wired totally wrong.

Too confused at this point.

Not if you have no power at the stat. I would say you have a broken wire somewhere. How many volts are you getting between r and c at the board? 28 volts??

If you jump wires at the control board in the air handler does anything work? Fan? outdoor unit? Heat?

not if you have no power at the stat. i would say you have a broken wire somewhere. how many volts are you getting between r and c at the board? 28 volts?????

Yes... 26-28V

You have 24 VAC and the transformer is good and so is the circuit breaker in your tests.

I'm looking at the pic in post #39. It appears that you have a 3 stage heat and cool of some sort.

There is something fishy with the three reds twisted together and the black wire connected to terminal R. That other thermostat wire going to the outside unit seems connected way wrong.

On the strip:

Jumping R to G should make the fan come on.
Jumping R to W1 should make the heat come on.
W2 and W3 are not connected and this is 2nd and third stage heat.

R and C should have 24 VAC on them. They do, so the tstst should light up

R is either not going to the tstat? It's also black and not red. This raises some real wiring flags.

1. Wrong thermostat - not 3 stage heat
2. The AC contactor coil being wired totally wrong.

Too confused at this point.

It's not likely the issue with the wiring or how it's set up, (although I understand, sometimes things are not set up the way it should be!) as everything has been running fine since I bought the house end of 2002, so the house is about 6-1/2yrs now. This issue just popped up now.

You need to check for 28 volts between the 3 buged red wires and C at the board

if you jump wires at the control board in the air handler does anything work? fan?, outdoor unit? heat?

Nope... I put the green(G) to black(R)... nothing happened.

Is that black tied in with the 3 red? I can not see it from the pic?

you need to check for 28 volts between the 3 buged red wires and and C at the board

You mean check for 28V between the 3 red wires in the wirenut, and the blue wire at C?

Yes, and where does the black go that is hooked to r on the board, and where doe that blue go that is hooked to r on the board?

You mean check for 28V between the 3 red wires in the wirenut, and the blue wire at C?

3 Red wirenutted wires to C shows no power
To G or W1 - same thing - no power

To R - 26V
To W2 or W3 (even though empty) - 26V

This is why your stat is not lighting up 1 of the 3 red wires sends power up to the stat, and it has no power. The other one goes to the outdoor unit? Where is the 3rd one going??

yes, and where does the black go that is hooked to r on the board, and where doe that blue go that is hooked to r on the board?

The black on R goes into that brown jacket wire. Also on that brown wire, you can see a single red wirenutted to the other 2 reds. Okay, this brown wire with the black and red leads to 2 thin black wires that goes into a white pvc pipe that goes into the ground of the garage floor. I am thinking it leads to the back to the AC condenser.

The blue at the rear row of R, that gets capped (clear plastic cap) with the darker blue that leads to the transformer (red coil).

Ok where is the third red wire going? From the wire bug?

Ok where is the third red wire going? from the wire bug?

The 3rd red wire goes into one of the 3 brown wires you see in the pic.

1st brown wire goes into the ceiling, which I believe leads to the tstat.

2nd brown wire only has a black and a red (the rest are cut off) that goes to the white pvc pipe going into the floor, which I described earlier. This could be a sensor, or something... I don't know.

3rd brown wire also goes into the floor, this one I believe goes to the rear condenser.

I'm puzzled here, if there is 26V between R and W1, G, C
And R is connected to the wirenutted 3 reds
Why is there no power between the 3 reds and W1, G, C?

http://img194.imageshack.us/img194/802/transformerfusevac03.jpg

[QUOTE=KenLoh;1739209]I'm puzzled here, if there is 26V between R and W1, G, C
And R is connected to the wirenutted 3 reds
Why is there no power between the 3 reds and W1, G, C?

Never mind... my bad... black is not connected to the 3 reds, Let me double check.

Josh is on the right track. I'll not be available for much of today.

At this point I see a serious thermostat wiring problem and you may just have to chase them down.

You have:

The air handler terminals and colors to two different cables. 1: ouside, 2 thermostat

The thermostat has colors and terminals.

There should be one loose end at the air handler.

Terminal Y of the stat heads outside, so it jumps cables. In real system, this would be the yellow wire. So, it alone would have a wire nut.

This looks like an electric furnace and not a heat pump.

You should have a table like:

Tstat
1-Red to R
1-Blue-to C

Etc

Outside unit (only two wires are connected)
2-Red to ouside contactor
2-yellow to outside contactor
2- Brown (No connection(

Air handler
R to 2-Red
R to 1- Red
C to 2-blue

1-brown (wrapped or not connected)

The 1 refers to the cable to the stat
The 2 refers to the cable to the AC unit

If you can put this together Josh should be able to help you figure it out.

The wires on my tstat are
Red-R
Green-G
Yellow-Y1
White-W2
Orange-W1/O/B
Nothing-Y2
Blue-C

In reality, you need a 3 stage heat, and probably 1 stage cool. The tstat is a 2 stage heat and 2 stage cool.

It can be made to work with a couple of jumpers, but the right stat might be more energy efficient.

Generally, you can have more stages than required, but you should not have less.

I think you have an electric furnace with 3 stage heat and one stage cool. Am I correct?

Jumping the terminals at the furnace should cause things to happen.

I think in an electric furnace, I'm not sure what controls the fan, It's eitier the furnace or the thermostat.

At the furnace:

R jumped to G; turns on fan
R jumped to W; turns on heat and may turn on fan sometime later.

Check that as it stands.

Also go outside and follow the thermostat wires and take a picture of that. There should be two wires and two power wires going to the same object.

Make sure the new thermostat has an electric furnace option in it's setup.

It looks like you had the wrong thermostat from the get go.

I think that power is not getting to the stat because the R wire is out of place. It's also why the AC doesn't work.

I'm getting ready to start over.

If the tsat has:
1) an electric option
2) R to G at the furnace turns on the fan
... R to W1 turns on the heat (note fan behavior, it may be delayed) Connect for no more than about 5 minutes

Are you ready to rip all of the t-stat wires out and start over?

I hope you don't have a heat pump with emergency heat. If that were the case the outside unit would run in heating and cooling mode.

Am I correct that the outside unit doesn't run when heating?

I hope you don't have a heat pump with emergency heat. If that were the case the outside unit would run in heating and cooling mode.

Am I correct that the outside unit doesn't run when heating?
I can't recall... I think the outside unit runs when heat is on. I thought it did, until you ask, I'm not sure.

I have tried jumping wires at the tsat, nothing happens. R to G, R to Y... even waited a few minutes... nothing, not even fan.

I have also connected the R(black) to Green at the air handler... nothing, no fan.
Or should it be Green to C instead?

OK, time to take a picture of the outside unit where the tstat wires go.

In reality, you need a 3 stage heat, and probably 1 stage cool. The tstat is a 2 stage heat and 2 stage cool.

It can be made to work with a couple of jumpers, but the right stat might be more energy efficient. There is no power at the wires coming out of the wall to the tstat.


Generally, you can have more stages than required, but you should not have less.

I think you have an electric furnace with 3 stage heat and one stage cool. Am I correct? I don't understand what a 3 stage heat or 1 stage cool mean, sorry.


Jumping the terminals at the furnace should cause things to happen.

I think in an electric furnace, I'm not sure what controls the fan, It's eitier the furnace or the thermostat.

At the furnace:

R jumped to G; turns on fan
R jumped to W; turns on heat and may turn on fan sometime later.

Check that as it stands. I've tried R to G - nothing happened. I'll try again. Will the fan work with the air handler panel open? I did jump then close the panel just to be sure. Nothing happened either.


Also go outside and follow the thermostat wires and take a picture of that. There should be two wires and two power wires going to the same object.The tstat wires that go to the rear condenser unit, runs underground, I think. If you look at the first few pics I posted of the condenser, you should be able to see them in there.


Make sure the new thermostat has an electric furnace option in it's setup.

It looks like you had the wrong thermostat from the get go.

I think that power is not getting to the stat because the R wire is out of place. It's also why the AC doesn't work.

But everything was working fine for 6-1/2 yrs.

IT looks like you have a Heat Pump and you did take a pic of th ouside unit. I just missed it. There are a BUNCH of wires connected to a terminal strip.

What are the designations and colors.

I hope you bought a heat pump thermostat with the right amount of stages.

OK, time to take a picture of the outside unit where the tstat wires go.

The first pic that I posted in this thread, does that help? IF not I'll go take a closeup.
I tested there, no power at those 24V terminals.

I kind of got diverted to focus on the air handler side, and ruled out the outside condenser. Could that circuit board where the 24V terminals are on, be faulty?

IT looks like you have a Heat Pump and you did take a pic of th ouside unit. I just missed it. There are a BUNCH of wires connected to a terminal strip.

what are the designations and colors.

I hope you bought a heat pump thermostat with the right amount of stages.

KISS... I think you misunderstood. I did not buy a new tsat. Was going to, but since there is no power from the wires off the wall, I ruled out a faulty tsat.

Should I get a new tstat?

There are a BUNCH of wires connected to a terminal strip.

what are the designations and colors.


Do you mean this terminal strip? Can you see from this larger pic?

http://img36.imageshack.us/img36/3148/condenser04.jpg

I think you are going to find that wherever the black wire and the 3rd red wire goes is going to be your problem. A temp sensor, or a pressure swith maybe

I think you are going to find that where evre the black wire and the 3rd red wire goes is going to be your problem. a temp sensor, or a pressure swith maybe

Josh, I just found out that black and red (split from 3 red wirenut) that leads to the pvc pipe is a switch/sensor for overflow.

Hold on, I just took some pics of the air handler and pipes etc. Should give a better idea of what kind of heater/system I have.

For like drain water? This could defentally be your problem

for like drain water? This could defentally be your problem

Maybe I have a clogged pipe there and it's shutting the system down? Hmm.. let me take a look and see if I can dig in that pipe where the wire goes in...

These should help answer some questions:


http://img194.imageshack.us/img194/1664/airhandler08.jpg

http://img194.imageshack.us/img194/604/airhandler09.jpg

http://img194.imageshack.us/img194/787/airhandler10.jpg

http://img194.imageshack.us/img194/3663/airhandler11.jpg

I bet this is your problem this is a drain safety. That is why after awhile your t-stat will light back up after the water drains. You can jumper this switch to make sure it is the pproblem. Then if it is unclocge the drain.

Yessss!!!!! Bingo!!!!!
:D :D :D :D :D

http://img41.imageshack.us/img41/6392/yeababyyea5mn.gif

Great!! Glad we finally got to the bottom of this problem.

Josh, I want to thank both you and KISS (what's your name! ) for hanging in there with me. You guys been very helpful. Mann... a simple thing like that and I went on the wild goose chase, LOL!
But I have learned a lot from this experience. Before this I had no knowledge or experience with the HVAC system at all.

Thank you once again! Appreciate the help and support Greatly! I hope someone else in the future will benefit from this long thread... hey, lots of pictures!! LOL!

Yes I am sure someone will have this same issue with ac season coming on strong. Now all you have to do is put everything back the way it was lol. Have a great weekend.

I regret doing something in the haste and excitement... when I opened up the cap to the pvc pipe, saw the water, I used a thin dowel and gently pushed it into the pvc pipe. The water globbed and drained down. I should have used a wire to fish up whatever that's clogged in the pipe!

Oh Well... I'll keep an eye on it. Hope it was just a ball of lint or something.

Hey Josh and KISS... I'll buy you both a beer! Let's Go!:D

Sounds good, you should be good for awhile now. Just rember if this ever happens again. If you have enough points you can rate mine and kiss's answers. Would really be apreaciated. If you ever need anything else look me up. Josh

sounds good, you should be good for awhile now. Just rember if this ever happens again. if you have enough points you can rate mine and kiss's answers. would really be apreaciated. If you ever need anything else look me up. Josh

How do I rate answers for you and KISS? There are only "Rate this answer" buttons on my own posts. I don't see any option on other's posts. This is different than those on other forums I'm on.
Please elaborate on how to...

I clicked on the green reputation icon, it doesn't give me the option to give points. Weird. Maybe one has to be a member for a certain period, or after a certain number of posts before this function is enabled?

Btw, Thanks for your points, Josh! :)

Mann... it sure feels good to have AC again... something we all take for granted sometimes. And it feels even better to have finally nailed the problem!:D


For general knowledge, and for future reference, what kind of system/unit do I have? (heat pump/electric furnace/what stage? Etc). How should I describe it? The last few pics I posted should help I hope.

You have a heatpump with 2 stage electric heat.

you have a heatpump with 2 stage electric heat.

Thanks!

Did you figure out how or why I can't give rep points?

I disagree, your system is a 3 stage heat heat pump with backup electric heat and 1 cool.

Your thermostat is 1 heat/1cool heat pump with 3 stage electric aux heat

You might want to consider connecting a jumper between W2 and W3 at the furnace.

Right now, you are not using the 3rd stage aux heating.

You might actually have a 4 stage heating system:

Y, Y+W1, Y+W1W2, Y+W1+W2+W3

The thermostat is not the right one. You can get a lot better energy savings if a sensor and the proper thermostat is placed outside.

The sensor determines when the Heat Pump is allowed to run.

On the transformer you should have 120v one side and the other side you should have 24v. Something is causing the power to go out.IT might be your fan motor/run cap.

I disagree, your system is a 3 stage heat heat pump with backup electric heat and 1 cool.

Your thermostat is 1 heat/1cool heat pump with 3 stage electric aux heat

You might want to consider connecting a jumper between W2 and W3 at the furnace.

Right now, you are not using the 3rd stage aux heating.

You might actually have a 4 stage heating system:

Y, Y+W1, Y+W1W2, Y+W1+W2+W3

The thermostat is not the right one. You can get a lot better energy savings if a sensor and the proper thermostat is placed outside.

The sensor determines when the Heat Pump is allowed to run.


There are only 2 heating elements how can it be 3 or 4 stage? Inless I missed something in the picture.

There are only 2 heating elements how can it be 3 or 4 stage? Inless i missed something in the picture.

If I'm not mistaken, I think the fins below the fan cools or heats, and there is an additional set of heat elements above the fan?

How do I rate answers for you and KISS? There are only "Rate this answer" buttons on my own posts. I don't see any option on other's posts. This is different than those on other forums I'm on.
Please elaborate on how to....

I clicked on the green reputation icon, it doesn't give me the option to give points. Weird. Maybe one has to be a member for a certain period of time, or after a certain number of posts before this function is enabled?


Now I see the "Rate This Answer" option appear in all the posts. Incidentally, my "New Member" has been upgraded to "Junior Member". So I think it must have been a feature made available only after a certain number of posts.

I need to come back to this. Take a look at:

http://www.white-rodgers.com/wrdhom/pdfs/instruction_sheets/37-4244E.pdf

In this system W2 and W3 are not connected, so those stages are not used or are not present.

W1 could mean heat strip #1
W2 could mean heat strip #2 (not connected)
W3 could mean heat strip #1 and #2 (not connected)

Y + O/B can mean heat pump

Right now, confused.

Ken: That's how you can have 3 stages with two strips.

It's also how you can have 4 total heat sages.

Something is difficult to understand here.

W1 evidently is not connected to Y1 or O/B and therefore W1 isn't part of the heat pump circuit.

More reading...

Here is a 4 heat/2 cool stat.

Buy Honeywell VisionPro IAQ Programmable Universal Thermostat with Total Home Comfort Control | Honeywell YTH9421C1002 (http://www.iaqsource.com/product.php?p=honeywell_yth9421c1002&product=110092&category=554)

I need to look at it a bit more.

Got some advice. Best one can tell there are 4 stages of heat.

You might consider jumping W1 to W2 to W3 assuming you have a 2 stage heating stat. From my advice, the air handler will sequence stage if the thermostat doesn't. It might provide better recovery on cold days.

I have a similar setup and problem. My question is: if there is no 24 VAC between R & C. the fuse is good, and there are no loose wire or connections that I have found. Is it most likely the board that is blown?

I have no fan when I switch tstat to fan on, and of course no a/c at all.

Thanks
Sgtaxe



This reads well. Kinda interesting reading.

I'd focus your immediate attention on the following two terminals. R & C.

The next time it fails check R & C at the furnace first and R & C at the thermostat. There should be 25 VAC between these terminals at all times.

Those two terminals should go to the transformer in the air handler. There should be 4 terminals or wires. Two go to 120 VAC and two go to R &C.

Look for any loose connections in any of these wires.

There also may be a 3 A automotive type fuse on the control board. Re-seat that.

You need 24 VAC between R & C for the tstat to have power.