[chhfsc]

Replaced old honeywell mechanical thermostat with white rodgers 1F82-261. Display only comes on with battery installed. AC or heat does not come on with changing temperature setting. The wiring is

R - red
G - green
O/B - orange
Y - yellow and black
C - blue
L - no connection
W2 - white, jumper to E
E - jumper to W2

What is the correct wiring? Please help

 

[Houston204]

Remove the panel to the air handler and write down the stat wiring connections that you see and post this information here.
Check the 5 amp blade type automotive fuse while in there.

Your common wire or fuse (or both) is probably the problem.

I usually take a picture of the existing wiring before removing any wires.

 

[rydan]

Replaced old honeywell mechanical thermostat with white rodgers 1F82-261. Display only comes on with battery installed. AC or heat does not come on with changing temperature setting. The wiring is

R - red
G - green
O/B - orange
Y - yellow and black
C - blue
L - no connection
W2 - white, jumper to E
E - jumper to W2

What is the correct wiring? Please help

Your wiring looks correct... for a typical thermostat install.. but HOUSTON is right, you probably have a wiring issue within your airhandler. Most likely a wiring issue & now, probably a blown fuse (if you have an inline fuse)... worst case a blown transformer

 

[chhfsc]

rydan, Houston204

Wiring in the unit outside the house is:
O - orange R - red W2 - white
Y - yellow C - black

Wiring in the unit in the attic (air handler?) is:
O - orange+light orange R - red+light red W1 - white+off white
Y - no wire C - black G - green W2 - no wire

Wiring and voltage in the thermostat with respect to R - red:
O/B - orange 31V W2 - white, jumper to E 31V
Y - yellow+black 31V C - blue 17V G - green 31V L -no wire 17V

Should the black wire be connected to C instead of Y in the thermostat?
If so, where should the blue wire goes?
Is the transformer blown? How to check?

 

[JScotty]

rydan, Houston204

Wiring in the unit outside the house is:
O - orange R - red W2 - white
Y - yellow C - black

Wiring in the unit in the attic (air handler?) is:
O - orange+light orange R - red+light red W1 - white+off white
Y - no wire C - black G - green W2 - no wire

Wiring and voltage in the thermostat with respect to R - red:
O/B - orange 31V W2 - white, jumper to E 31V
Y - yellow+black 31V C - blue 17V G - green 31V L -no wire 17V

Should the black wire be connected to C instead of Y in the thermostat?
If so, where should the blue wire goes?
Is the transformer blown? How to check?

OK yeah I think I see your problem Black should go to C, the Blue wire probably isn't used. I would think the way it was wired it would've blown the transformer if you tried to turn it on for regular heat or cool (power would pass from R to Y for heat pump, you have Black in Y terminal at stat, Black goes to common in board, sounds like a short from R to C) however the readings you post look like you have 24 volts to the stat so it appears to not be blown.

 

[chhfsc]

Connected the black wire to C, blue wire is disconnected, O/B terminal switch set to O.
Display is now working without battery. Heat and fan turns on/off according to thermostat temperature.
Wiring and voltage in the thermostat with respect to C:
R – red 30V, O/B - orange 0V, W2 - white with jumper to E 0V
Y - yellow 30V, G - green 30V, L -no wire 0V

But AC does not work. When switch to AC, the unit in the attic seems to come on, but no fan or cold air. The display goes blank after a few seconds.
The voltage on the thermostat with respect to C is:
R – red 30V, O/B - orange 0V, W2 - white with jumper to E 30V
Y - yellow 30V, G - green 30V, L -no wire 0V

When I change the O/B terminal switch to B, the AC would work, but the heat does not.
Any suggestion? Should the blue wire be connected, it has ~20V on it?

 

[beenthere]

What brand is your outdoor unit.

 

[chhfsc]

The outdoor unit is carrier 38ycc030300.

 

[beenthere]

Thermostat should be set to O for cooling on that unit.

 

[chhfsc]

Thermostat should be set to O for cooling on that unit.

Hi Beenthere, the thermostat is set to O.
Connected the black wire to C, blue wire is disconnected, O/B terminal switch set to O.
Display is now working without battery. With switch set to Heat, the heat and fan turns on/off according to thermostat temperature.
Wiring and voltage in the thermostat with respect to C:
R – red 30V, O/B - orange 0V, W2 - white with jumper to E 0V
Y - yellow 30V, G - green 30V, L -no wire 0V

When switch to Cool, AC does not work, the unit in the attic seems to come on, but no fan or cold air. The display goes blank after a few seconds.
The voltage on the thermostat with respect to C is:
R – red 30V, O/B - orange 0V, W2 - white with jumper to E 30V
Y - yellow 30V, G - green 30V, L -no wire 0V
When I change the O/B terminal switch to B, the AC would work, but the heat does not.

Should the blue wire be connected? Does it control the change over relay?

 

[JScotty]

Hi Beenthere, the thermostat is set to O.
Connected the black wire to C, blue wire is disconnected, O/B terminal switch set to O.
Display is now working without battery. With switch set to Heat, the heat and fan turns on/off according to thermostat temperature.
Wiring and voltage in the thermostat with respect to C:
R – red 30V, O/B - orange 0V, W2 - white with jumper to E 0V
Y - yellow 30V, G - green 30V, L -no wire 0V

When switch to Cool, AC does not work, the unit in the attic seems to come on, but no fan or cold air. The display goes blank after a few seconds.
The voltage on the thermostat with respect to C is:
R – red 30V, O/B - orange 0V, W2 - white with jumper to E 30V
Y - yellow 30V, G - green 30V, L -no wire 0V
When I change the O/B terminal switch to B, the AC would work, but the heat does not.

Should the blue wire be connected? Does it control the change over relay?

No the orange wire that connects to O in your outside unit should be doing that. If I'm reading your descriptions correctly you're saying the blue wire isn't connected to anything in either the furnace or the outside unit. Therefore it shouldn't do anything. Unless there are other connections made somewhere outside your furnace. And the fact that you say there is no wire connected to Y in the furnace would be an indicator that some wires are connected outside the furnace. As Y from the thermostat has to connect to the wires going to the outside unit.

 

[beenthere]

Post pic of wire connections in outdoor unit, and indoor unit.

 

[chhfsc]

attached are pics of attic unit and outdoor unit.

 

[beenthere]

Can't see which thermostat wires connect where in outdoor unit. But there is a chance that your new stat is the problem if you didn't change any wires outside.

 

[chhfsc]

Can't see which thermostat wires connect where in outdoor unit. But there is a chance that your new stat is the problem if you didn't change any wires outside.

The thermostat connection pic is attached.

Thermostat wire...... outdoor unit wire
Red......................... Red
White.......................White
Black........................Black
Orange.....................Orange, yellow

 

[beenthere]

It looks like both yellow and both orange wires are in the same wire nut. If so, they shouldn't be.

 

[chhfsc]

It looks like both yellow and both orange wires are in the same wire nut. If so, they shouldn't be.

After the yellow and orange wires are separated, the heat worked properly. But when the thermostat is set to AC, the fan in the attic comes on, but the outdoor heat pump does not come on.
Checked the connection from thermostat to Attic to Outdoor units, the connection is:

******************************
Thermostat____Attic_______ Outdoor
R -------------------Red-------------Red
G-------------------Orange
O/B----------------------------------Orange
C-------------------------------------Yellow
W2----------------Purple----------White
E jumper to W2
Y no connect
*********************************
There is black wire from the Attic unit connected to a black wire from the outdoor unit, but not connected to the thermostat. Should these 2 black wires be connected to the C terminal of the thermostat?
And the yellow wire from the outdoor unit connected to the Y terminal of the thermostat instead of C?

 

[Houston204]

Connect black to thermostat C.
Connect Yellow to thermostat Y.
Blue is not used.


Looks like stat black also needs to be connected to the air handler C.
I only see one black wire there, when I should see two.



Thermostat__________Attic_______ Outdoor
R (red) -------------------R-------------Red
G (green)-----------------G
O/B (orange)------------------------------Orange
C (black)-----------------C----------------black
W2 (white)----------------W1----------White
Y (yellow)-----------------Y------------Yellow
E jumper to W2

Your yellow wires do not connect to the air handler Y.
I would have made this connection, but it probably does not affect anything with this older air handler.

 

[chhfsc]

:thumbup:A late thank you for all your advice.
Re-wired the thermostat, air handler, heat pump per the last input, it works!!!!