[dsabins]

Hello:

I saw your name on an internet search for thermostat wiring problems, so I thought I would try you for this one. I could not get help elsewhere.

I have an oil burner, and a separate a/c unit. I installed a programmable thermostat 2 years ago that works well, although the location is in a bad place since we did some remodeling and an addition. So, I bought a TOTALINE 1000RF wireless thermostat and 1100REC receiver. The plan was to put the receiver in the same place and put the transmitter near the bedrooms.

The current wiring scheme has these wires

RH,RC,Y,G,W

The new thermostat has R/RH,Y,G,W,C - the R/RH is one terminal and there is no mention of an RC whatsoever in the manual or sample wiring diagrams. No matter how I hook it up, it does not work. At the furnace end, it looks like I have 2 transformers, and one of them looks to control a relay of some sort. This transformer/relay set up is inside the furnace so I assume that is what it operates. The other transformer is external to the furnace. I tried to trace the wires, but they switch over to the wires that go to the thermostat somewhere in the walls.

Any help on this one? Of course the on line store I bought it from is absolutely no help (thermostatshop.com). No return calls nor will they give me an RMA to return it. If I can get it to work, it would be the perfect solution. And, no, there is no way to re-wire the run to the desired location.



Thanks in advance for any help.

Dean Sabins

[labman]

First the basics:

Usually there is a 24 volt AC transformer in the furnace with the secondary winding connected to a red wire running to the thermostat and a blue wire, common, to the gas valve, A/C relay, and fan relay. From the thermostat there will be white wire to the gas valve, yellow to the A/C, and green to the fan. The thermostat is wired to switch the power from the red to the white, yellow, and green as needed with the blue completing the circuit. Most thermostats and furnaces have the contacts labeled R, B or C, W, Y, and G for the corresponding wire colors. It may be wired to have the A/C control wires return to the furnace and its controls and then a second wire goes to the A/C unit. Internal wiring may replace the green wire if the thermostat does not give you the option of fan only or continuous fan. Digital or programmable thermostats may need the blue wire connected to them.

I do not understand why they add a second transformer in some cases. Did any of the wires from the external transformer run to the old thermostat? Of course the external one could be for a door bell or something and have nothing to do with the furnace. You should be able to mount the receiver near the furnace where you have access to all the wires. The W, Y, and G are no problem. Do you have a red wire coming from the transformer in the furnace that was connected to RC and RH? If so, connect it to the R/RH. It is power in. To run on power from the thermostat, the receiver needs a return to the thermostat. You need a blue or other wire running from the other terminal to the C contact of the receiver. You new thermostat should then work. The transmitter is battery powered or uses household current?

[dsabins]

Wow! Thanks for the quick reply. The transmitter is battery operated. It sounds like I should place the receiver at the furnace so I can get the wires straight. Both transformers are connected to wires that go to the current thermostat. They are spliced wher I can't see them. I am going out of town for the weekend, so I will see if I can decipher it when I come back. From what you explained, it seems that I should eliminate one transformer, and tie the RC and RH together. I notice that some thermostats have both an RC and RH which are normally jumpered.
Again, let's assume I do a continuity test on the existing wires to see where they wind up. The RH and RC are power, and the Y,W and G turn on the heat,a/c, and fan when connected to power. This means I am 'missing' a common to complete the circuit.
If I move the receiver to the furnace room, and use one transformer, one side of the transformer would be R, then other C, with the fan (G), heat (W) and a/c(Y). So without a thermostat, touching the G to the R would turn on the fan, W+R would turn on the heat and R+Y would turn on the A/C.
Is that correct? Thanks again for your help. Oh, and also, there is no wiring block at the furnace, per se, just a jumble of wires. So if my logic above is valid, I could probably firgure it out.

[labman]

You need to check whatever the second transformer is connected to at the furnace plus the pair of wires out to the A/C unit. Then make sure the same wires from the internal transformer connect to it instead. You should already have the red, white, yellow, and green coming out of the furnace. If there isn't a blue running from the transformer to the thermostat, you would have to add a wire to the C. You are correct about R+G etc. That is all the thermostat does besides sense temperature.

[dsabins]

:D Hello: Again, thanks for the help. I traced all the wires. The second 'mystery' transformer was connected to a defunct humidifier, so that is out of the picture. Here is what I have. There is a 5 place terminal block attached to the 'good' transformer that has the expected YWGCR connections, however, they are not hooked up that way.
There are two (2) 3 conductor wires going to the thermostat one with Red and White (blue not used)- I'll call these R1,and W1. The second is a red, blue and white called R2,B2 and W2. There is a red and white going to the outside a/c unit called R3 and W3

First of all, the transformer leads are connected to C and G on there terminal block. The first letter in each line below is what is on the transformer block:
Y is connected to nothing
W is connected to W3 and R2 (which is labeled Y at the thermo)
G is connected to W2 (which is labeled G at the thermo)
C is connected to R3
R is connected to B2 (which is labeled RC at the thermo)

There is also a Honeywell Intermittant Ignition device that has R1 (labled RH at the thermo) and W1 (labled W at the thermo).

Now I am more confused. I guess the best bet is to eliminate the wiring to the thermo and wire up the new thermo receiver at the furnace properly using the transformer terminal block with the conventional letter codes. Help me out one more time. Remember, there is no RC connection available on the new thermo receiver, only W1/O,W2,Y1,Y2,R,G,C
Thanks, Dean

[dsabins]

I originally said that the wires from the transformer are connected to G and C on the transformer terminal block. These now appear to be connected to a relay below the transformer. I guess this is the fan relay for the A/C. I believe there is also a temperature related device that turns the fan on/off when the air temp raises/falls to a certain level. I see the dial moving when the furnace heats up. I hope this makes more sense.

Dean

[labman]

Pick one red, white, and blue cable.

Then starting at the receiver/wire/terminal block/wire/furnace connection

R red R red Transformer
C blue C blue to the other transformer terminal
W1/O white W white to the ignitior, pump relay, etc. whatever the old W from the thermostat connected to.

You then need to pick 2 of the 3 wires in to other cable.
Run one from Y1 at the receiver to Y at the furnace. Also connect the red wire to the A/C unit to it.
Use a second wire to connect G to G
Connect the white wire from the A/C to the C terminal.

To make this work, you need to identify the wires at the furnace that were connected to Y, G, and W terminals of the old thermostat and connect them to the correct terminals on the block. You seem to have found the fan relay. All the relays need to have one side of the coil connected to the C side of the transformer. If the wires are long enough, it won't hurt to bypass the terminal block.

I hope the above works. If not, post back with what you find out, and I will try again.

[dsabins]

Thank you for decifering the riddle. This makes perfect sense.

If this works, can I send you a gift card or something?

Warmest regards for the Holiday Season.

In my house, we say Merry Christmas, Happy New Year!

And, thanks for your help (yet again).

Dean

[labman]

Best thing to do is to post back when you have it working and say so. That will make me feel good, and encourage others needing help.