Ask Me Help Desk - No Power to A/C Thermostat

Quote:

Originally Posted by Joshdta

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.

Quote:

Originally Posted by Joshdta

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?

Quote:

Originally Posted by Joshdta

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?

Quote:

Originally Posted by Joshdta

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

Quote:

Originally Posted by KeepItSimpleStupid

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

Quote:

Originally Posted by Joshdta

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?

Quote:

Originally Posted by Joshdta

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?

Quote:

Originally Posted by KenLoh

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??

Quote:

Originally Posted by Joshdta

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?

Quote:

Originally Posted by Joshdta

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/img194/8...rfusevac03.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?

Quote:

Originally Posted by KeepItSimpleStupid

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.

Quote:

Originally Posted by KeepItSimpleStupid

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.

Quote:

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.

Quote:

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.

Quote:

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.

Quote:

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.

Quote:

Originally Posted by KeepItSimpleStupid

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?

Quote:

Originally Posted by KeepItSimpleStupid

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?

Quote:

Originally Posted by KeepItSimpleStupid

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

Quote:

Originally Posted by Joshdta

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