gas furnace turns off at night???

[dcusack]

Hello, This I my first time on this sight, I heard great things about it and I am hoping I can get some answers to my questions here. This has been going on for a while and its is driving me crazy. My Heater seems to always go off at night. I turn it off then on at the thermostat and nothing happens, I have to go into the basement and turn the furnace off at the breaker and then back on. I do this maybe once or twice, then it kicks on and works great all day, going on and off like it should. but once we are in bed, it seems to turn off and never kick back on. It doesn't happened every night, but it does happen at least 3-4 time a week. Could the thermostat in my dinning room be bad? I replaced the battery the other day. Our home is 10 year old and I am not sure what brand I have, since there are no labels on it at all. I am guessing its a builders grade unit. Any help he would be great. It getting cooled and my 4 year old sons room gets really cold when this happens. This will be a another topic.

[HayZee518]

furnace

how many wires are connected to the thermostat? Two?

[dcusack]

how many wires are connected to the thermostat? Two?

I attached a picture of the unit and all the wires. there are 4 wires, Greenm Blue, white and red with a black jumper wire, from red ( RH) to (RC). I also noticed that the blue wire is connected to the Y. I am not sure why the picture cant be open to offer a better view.

[dcusack]

I came down today and my house was 61 degrees. So, went to the basement and flipped the breaker off then on and looked thru the clear eye port and noticed that not all 6 flames would started up, maybe 4 to 5 did. I also noticed it only tries to fire up the system 2 times and if all flames are not going, it shuts down and will not try to restart. I guess this is a safety feature. So, I flipped the breaker off then on 2 -3 more times and eventually all 6 flames finally started and the heat kicked on. Any ideas what would cause this ?

[HayZee518]

furnace

if you have access look at the flames and see if they are impinging on the thermocouple. the thermocouple is a safety device. if it don't detect a flame it will lockout your system. by shutting off your breaker and turning it on again you are resetting the whole control circuit which includes the lockout.
your system will have one or the other safety lockouts.
a thermopile generates a dc signal to the main gas valve.
a thermocouple detects a flame and keeps the fire going. what it does is monitor the space between the gas jet and ground. in the presence of a flame, the circuit changes its characteristics to produce a dc current which is readable by the safety circuit. no flame, no dc signal. It is important to have a good ground for which to reference the flame to.