I've found GregN had the same problem as me back in Nov 2005. I've read the all the posts, I don't understand how he wired the P474-1100REF with the 2 wire from old round thermostat.

I've try the 24vac on the R and the other wire on W, and the system works sometime and the receiver LED dimmed and it doesn't seem to recover and fail to response to the wirless remote.

Can someone explain to me how Greg resolved this.

Thanks

Peter

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. The thermostat is wired to switch the power from the red to the white 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.

''I went back and started over again. R to R and W to G and C to C and everything worked great. Thank you for patience and assistance. I hope this post will be of some service to others.''

It sounds like Greg had a furnace where the gas valve etc. was activated by power to the G terminal. Only Greg can give more details. You could try a PM or email, just click on his name.

Do the directions for your receiver explain how it gets its power, battery, transformer, voltage stealing? If it has a battery, make sure it is good. If it needs a connection to the common side of the transformer, that should be easy enough if it is at the furnace. Otherwise, connecting the wire from the transformer to the R and the wire to the gas valve to W should work.

Like I said in my original post, I am replacing the round thermostat with the Totaline P474-1100REC and wireless remote. Please refer the link below for Docs.

Thermostats USA - Totaline Residential

From the wall I have 2 wires, one is Red which is from the 24vac of the transformer, the other White is connected to the Gas valve at the furnace, continue from the gas valve back to the common of the transformer.

I have the Red wire connect to the R on the receiver, and the White wire connected to the W on the receiver, the receiver actually started the furnace a few times when the temperature in the remote was below the setting, however, when it triggered the furnace, all the LED on the receiver were dimmed (I measured the voltage between R & W was around 10vac), and when the temperature in the remote was higher than the setting, the receiver fail to response (seem like not enough voltage to drive the unit), the only way I can get it going again to reset the unit by disconnecting the 24vac.

I think I understand how Greg solved his problem; he actually introduced a third wire from the transformer common to the Common of the receiver terminal, the reason I bought the wireless remote is to avoid pulling wire. The only alternative to mount the receiver close to the furnace and hope the wireless remote still work from the other part of the house.

Thanks for your reply.