[stitch626]

I have a SunTherm Electric heat and air system in my apartment and just bought a Ritetemp 6080 to replace the old out of date thermostat. In order to use the remote and other features you have to have the C wire connected and my system doesn't have that running through the wall. Does anyone know how to add a C wire or do I just put a jumper in the red wire over to the C port. I have a SunTherm Model 302-45-05-COB\CSA27-SB. Thank-you so much to anyone that can help me out with this.

[wmproop]

Run another set of tstat wires with what you need plus extra for the common/c wire///////is there something wrong with the tstat you are using now?

[stitch626]

No it's brand new just got it yesterday but the system I have doesn't have a wire for the c port it's a standard 4 wire run from the electric heat and air system. I'm sure it can have the c wire run from the unit to the thermostat but the apartment complex never installed that wire when they installed the units so I would need to run a new wire for it. I have the wire and I know where to attach it to the Thermostat but I'm not sure where I would need to attach the C wire on the a/c unit it's self as there are no diagrams I can find of where the common line out of the transformer is. I'm a little lost as to where I would attach the line is the main point and just need some advice on where that connection would be or how to find the right location to attach it.

[KC13]

If you have no interest in controlling the furnace blower for continuous operation, use the "Y" thermostat wire to control the "Y" and "G" circuits to the indoor unit, and use the thermostat wire that was previously controlling the "G" circuit for "C".

[stitch626]

OK so all I need to do is put the green wire to the c port and put a jumper wire between the y port and the g port and it will run like before just won't be able to turn on the fan without turning on the Heat or AC

[KISS]

Hey KC:

In AC mode the thermostat controls the fan, so, I think the idea of borrowing a wire is out. If the heat is electric and not a heat pump, then the thermostat controls the fan too.

There is a way to avoid running an extra wire, but it involves adding a complex kit.

I get the felling that the OP has no trouble running the extra cable. Just doesn't know where to connect it.

If this is a single stage AC, then there are two wires heading outside. One goes to Y and the other will end up at the low voltage transformer as common (C).

[stitch626]

Yeah I looked at the unit it's self and out of the top there are only 4 wires and when I open it I don't see the extra wire to connect to for C and am not real sure where I would add my own to run so I'm just trying to find where to link it at I have the extra wire for it already from the store just need to know where to connect it at

[KC13]

If you don't have a heat pump system (4 t-stat wires suggests you don't) and the blower is controlled by a sequencer for heating, my idea would work, although not ideal. If you already have the new wire and fishing it wouldn't be too difficult, then do so. If the indoor unit does not provide a "C" terminal, you would have to locate the low-voltage common circuit and tap into it somewhere. As K.I.S.S. mentioned, the outdoor unit would require 2 low-voltage wires, 1 to the "Y" circuit and the other to the "C" circuit. Locate them and you've probably found the best point to tap into the "C" circuit.

[stitch626]

OK I found the line running outside to the outside unit there is a red and a white line the white one is connected to the yellow wire coming out of the inside portion of the system and the red one is connected to the wire running to the thermostat it's the wire that is connected to the y port so to run the c wire I would just connect to the white wire or do I need to open the unit up and try to find the transformer and try to find where on that I need to connect to.

[KC13]

Based on your description, the white/yellow junction is the low-voltage common you are seeking. Turn off power to system and add your common wire to this point.

[stitch626]

Awesome you all are amazing thanks so much for your help.

[KC13]

Aw shucks, thanks. Spread the good word about us. Y'all come back now, you hear?

[stitch626]

Just to follow up I did that link and everything works awesome so again you all are great thanks so much and I deff will be letting everyone know about this site thanks again