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ericblis · Mar 2, 2006, 12:43 PM

I removed my thermostat to paint this winter, think I wired it wrong when I hooked it back up--- Now when I try my AC, it comes on (blower and outside unit) for a few minutes, then turns off. Then it doesn't come back on (outside unit). The heat works, although I can only seem to get it to run when the thermostat is set on emergency heat, rather than regular heat.

(see wiring diagram at http://www.dvmemories.us/hvacdiagram.jpg )

Here's what I have:
Thermostat:
Robertshaw 9620 (digital programmable)
Terminals available are C L R Y2 Y1 E G W2 O B

Furnace Blower Unit:
York Diamond 80 with White Rodgers 50a50-230 control board
Terminals available are C G R W Y

AC Unit:
Lennox HS14-511V-79P
Not sure about terminals yet... I know it is 2 stage, but I can't tell how to hook up the second stage to Y2 or how it is connected at the furnace...

The wire that comes to my thermostat goes like this
Wire Color Hooked to Control Board at
Blue Twisted w/fat blue to transformer and white to AC Unit
Orange C (along w/ other blue to xformer and orange to AC Unit)
Green G
Red R
White W
Yellow Y (along w/ yellow going to AC unit)

Can you help me hook it up right? Please? I've read about 50 posts online and some are similar, but I just can't decipher what I need to.
Thanks-

Eric.

labman · Mar 2, 2006, 01:29 PM

Y1 and Y2 should be the low and high cooling rates. They need to go out to the compressor unit. White wires normally connect the W terminals for heat. Often a blue wire runs for the C terminal out to the other side of the relay coils from the yellow.

Orange is most often part of the mode switching wiring on a heat pump.

The coil of the blower relay must be powered too for A/C. Normally the yellow wire does that, but in some cases it is the green. Normally the green is used for the fan on function.

If somebody else was giving good answers on heat pump wiring, I would quit trying.

Looking at your question again. Everything should be right except the thermostat. See if the outside unit has Y1 and Y2. If so, connect the same wires to them at the thermostat.

ericblis · Mar 2, 2006, 03:01 PM

Why is there a W2 but no W1 on the thermostat?

I'm not sure what to do with L, Y2, E, O, or B at the thermostat, and I assume the white goes to W2. Doesn't something need to be jumpered as well?

I'll check to see what is on the AC Unit itself, but even if it does have a Y2, would it go straight to the thermostat, or hookup at the furnace control board somewhere else since there is no Y2 at the control board?

What about the emergency heat?

labman · Mar 2, 2006, 03:19 PM

I am sure the connections at the furnace are the standard transformer common, fan relay, transformer hot, heat and A/C. The controls at the furnace may switch into emergency heat if the regular heat takes too long to heat the house.

Well you could try orange to O, white to W2, and yellow to Y1 and the small blue to Y2 and the fat blue to C.

ericblis · Mar 2, 2006, 05:57 PM

Ok, I think everything seems to be working, I traced everything out and checked everything- but one problem.
The orange (hooked up to C with the other power wire at the furnace control board) does not go to O at the thermostat. If I hook that up, the AC doesn't work at all. If I leave the O disconnected, it seems to work for now... at least for the past 10 minutes. On the thermosat, the O is for cool active reversing valve connection, and It seems that it should be hooked up to something? The Orange wire with power on it seems that it should be hooked to something as well.

Also wondering why the Y2 is not used on the thermostat, especially since an HVAC tech that came out when I had a different thermostat on there told me it was wrong, and I needed one that supported 2 stage cooling.

I have created a wiring diagram and placed it online at http://www.dvmemories.us/hvacdiagram.jpg
Maybe you can make some sense of it and let me know if it is right or not?

I think my thermostat is bad because the air ran for 20 minutes and the temp said 76, while 2 other thermometers said 73.
I blew a fuse when the orange wire was hooked up to O on the thermostat, so left it disconnected.

Still confused, but I'm making progress.

ericblis · Mar 6, 2006, 07:04 AM

Does this diagram look correct to you? What about the orange wire?

labman · Mar 6, 2006, 07:23 AM

The white wire is going have power constantly that way. Try disconnecting it from the furnace and running it directly from one Y2 to the other.

Understand I am not the top HVAC person we need here. Since nobody else is giving better answers on it, I am doing what I can.

ericblis · Mar 6, 2006, 07:43 AM

My concern is with the Y2 terminal at the thermostat (bottom of diagram) and the ORANGE wire that is coming down to the thermostat from C at the control box.

labman · Mar 7, 2006, 07:53 PM

Are you sure you drew the connections at the furnace right? Ordinarily one side of the transformer is connected to C terminal at the furnace and has blue wires connecting to the C at the thermostat and one side of the outside compressor relay coil. The other side of the transformer connects to the R terminal at the furnace and then connects to the R terminal at the thermostat. The orange wire would then run from the O terminal at the thermostat to the O terminal at the reversing valves.

ericblis · Mar 8, 2006, 05:09 AM

Yes, I double checked the drawing, and it is drawn exactly as wired.
I don't see anwwhere that the O wire would go to a reversing valve connection; is it possible that I do not even have a reversing valve? If so, there is no option to hook it up. I have not changed any wiring anywhere except for at the thermostat.

I wonder if I called my local HVAC folks that installed the system if they would take a look at the diagram, and then answer my question of Why did they tell me that I needed to purchase a 2 stage thermostat, when the Y2 is not even used? Were they just trying to sell me one at $175?

ericblis · Mar 28, 2006, 11:46 PM

My hvac friend looked over the diagram and told me to rewire it so the y2 on the thermostat goes to the y2 on the ac unit, also to bypass the transformer thing on the side of the control box.