Furnace questions

[HELLSUNICORN]

My home furnace has been acting up this week. And of course it is -2 outside and my friend who has his own Heating and A/C company is burying his dad today. So I am at the mercy of other "professionals"

My furnace is 30 years old and it has never given me any problems. This week the fan stopped working. I talked to my friend and he said most likely it is the fan timer switch and he gave me on to replace it. I replaced it and the furnace worked great for 3 days. Now it is doing the same thing.

I turn on the heat and it starts the pilot light but never turns on the burners. The blower motor will work in the on position but not the auto position.

I had a company look at it and he said he found a hole in my pressure tube and they cleaned the flame sensor. Worked great for 20 minutes. He charged me $212 and left. 30 minutes later I have the same problem. So I am waiting for them to come back.

If I shut the furnace off at the switch and wait about 20 minutes it will work fine again. Then It may work for 10 minutes or an hour and it starts acting up again.

Any ideas?? Thanks

 

[cad70]

It a VERY likely the flame sensor. If he used sand paper, then he ruined it. Usually, you can get by for a while if you use very fine emery paper, or even a dollar bill to remove the build up on it.
The flame sensor has 1 wire and 1 screw...get in there and clean it with a dollar bill, and you should be back up and running...

CAD

 

[zmaxmotorsports]

What kind of furnace is it?

 

[cad70]

Keep your oily fingers off of it!!!

 

[Rockhead261]

My furnace is 30 years old

Any ideas?? Thanks

Enough said, I think.

Not enough information in the post to give any insight. Make and model would be a good start.

 

[dreasoner]

Would a ten dollar bill work to clean it?

 

[HELLSUNICORN]

Yes, I know the furnace is 30 years old but if its a simple fix why condemn the whole thing? And up until today I have NEVER had a single problem with it. Its a RHEEM RGDC-06EC1ES 80 plus

 

[theoldwizard1]

It a VERY likely the flame sensor.

I second this !

 

[Showkey]

If the info given is accurate ? OP says..... It's NOT lighting........flame sensor is not involved until it lights and short cycles or does not stay lit.

Does it have failure lights on the board ?

Does it have gas flow and no ignition ? If there is gas flow can you blow the gas around ( just a little) the burner area and get it to light ?
If yes.........I will say check and clean the gas jets, Venturi and burner especially the cross over plate.

 

[HELLSUNICORN]

Yes, the information is accurate. The burners do not ignite. If they do ignite the fan will come on and it will work fine. The pilot does light when you turn the thermostat to heat. It is hit or miss if the burners will ignite after that. This is the problem.

I do not have a circuit board only an electronic box. Its very basic with minimal electronics.

 

[Showkey]

^^^^^^^^^^^^^
Good.........then the flame sensor is very likely NOT the problem.
If you have a strong pilot light or igniter then confirm gas flow. If you have gas flow then Clean burners and inspect the area around pilot. No rust is important to allow gas flow and the proper fuel air mixture.
Be careful not break the igniter/pilot.

 

[theoldwizard1]

If I shut the furnace off at the switch and wait about 20 minutes it will work fine again. Then It may work for 10 minutes or an hour and it starts acting up again.

I still say it is the flame sensor. Turning it off resets something.

When mine was acting up, I would just flip the switch, wait 30 seconds and turn it back on. The furnace would fire and run until the temperature in the house was high enough for the thermostat to kick it off.

Wait until the temp drops. Flip switch off and on and heat would come on. Great for when it quits at 3 AM ! Cleaned the sensor the next day.

 

[zmaxmotorsports]

Keep your oily fingers off of it!!!

 

[dreasoner]

I agree with showkey. Is this a sparker, HSI or a spark to pilot ignition? Are you getting the ignition circuit to work constantly or could there be a problem in the inducer proving consistently not allowing the ignition circuit to work. Turning power off then on would simply clear any faults from the board but would not solve the problem. To troubleshoot, you need to know WHERE in the sequence there is a problem. Inducer comes on and proves. Ignition sequence is number 2. Flame proof is 3. Finally the blower will come on and allow heat to work.