Ruud UGPH-05eauer Furnace Problem

[Curranpg]

Hi;

I have a ruud furnace that wont stay running. The unit goes through the start up cycle. The electronic igniter will start sparking, and the flame will ignite. It will run good for about 5-7 seconds, then it it will go out like the unit cut the gas off. I think it is a flame sensor, but I am not sure what it is called.

This furnase has a circuit board with 3 leds. two are green and one is yellow. It says Flame. This light flashes, but the other two stay solid green. I cant find a manual to see how to read these. Any help or pointers would be appreciated.

[Sjouke Burry]

Get it checked out. It should mean incomplete burning, and CO production. That costs money and is dangerous to your health.

[The Daring Dufas]

Does your furnace have a draft inducer fan? There can be one or two safeties with a draft inducer. A centrifugal switch on the fan motor and a diaphragm operated pressure switch to detect the air pressure cause by the running fan. The diaphragm switch will be round plastic or metal with a silicone rubber tube connected to the draft inducer housing. The air line could be bad or the connection to the inducer housing could be clogged. A piece of wire can be used to clear the connection and you can blow gently on the tube and listen for a click from the diaphragm switch. You can jump out the safeties to test them but never leave the furnace running like that. There are several sites where you can post a question about your problem. You'll need to post the model number and such because the folks reading your question can be dealers for your specific equipment.

TDD

[hrhofmann]

Couold there also be a thermocouple to sense thast the flame is actually on?

[The Daring Dufas]

No, it has an electronic igniter. Most new NG furnaces use a hot surface igniter which is a silicon carbide or nitride resister which glows red hot and will ignite the pilot when gas hits the igniter.

The igniter is used in conjunction with a flame sensor which is a heat resistant metal electrode that sticks into the pilot flame. Both devices are hooked to the control module which will turn off the igniter when a flame is detected by the flame sensor circuitry.

TDD

[Peter]

Try this link:

I know the file name says "Rgph" but when you examine the file, it is the 40 page installation manual for GPH models as well. Might match your furnace, or be close enough to be helpful.

[Curranpg]

Thanks!!! I was searching for this installation manual and couldn't find it.

[Curranpg]

I was able to clean the flame sensor and all is well. Thanks for the advice. My Yellow Flame Led is flashing which means it is a weak signal. I will order a new flame sensor and install it when it arrives.