I have a Bryant gas heater I had installed in 1991. It is a model 394 and the model number is 394GAZ203675. From time to time the heater stops coming on and of course I don't notice it until I start to get cold. As soon as I turn off the furnace and turn it back on it immediately starts up and works fine. In the past this might happen every week, every few months, etc. Lately about 2x per day. I have also noticed that the spark would time out before the heater would light. Again, it was fine after the heater was switched on and off. I haven't called a repair man up until now because I know how terrifically difficult it is to diagnose an intermittent fault and I don't want to pay for having parts taken off and replaced until the right one is finally discovered. Then I would get charged for all the parts including all the ones that were unnecessary. I checked this out with a heater repair outfit.

By the way sorry about the username. It gives me a fit of laughter every time I see it. By the way, I'm not.

This furnace has a diagnostic light that will indicate what the problem could be. There is a viewing port in the lower section of the furnace just below the mid point of the furnace. When you experience your next outage, look for a blinking light that will blink quickly a number of times then blink longer for a couple of times. Record this code and then remove the access panel to look for a sticker that says "LED CODE". This will steer you toward the issue and you may be able to figure out what is going on.

Without knowing this code, there is not much else I can tell you.

Get back to us!

I was away for most of the day and came home a short while ago. The temperature was down to 60° so I knew that the heater had stopped cycling. I looked for the viewing port, but there isn't any. The top part of the access panel is for air intake and the bottom part covers the fan motor compartment and has no openings in it. I looked through the slots in the upper access panel carefully, but could see no light. I took off the panel and looked around thoroughly to see if I could find anything. Unfortunately, I had no luck. Could there be anywhere else to look for the error code? There is no sticker inside mentioning "LED CODES." So that's the update. Anything else that I might do? Could error codes require some kind of device to read?

Find the control module. There should ba a small LED on it and maybe on the control itself a diagnostic chart.

If not, follow this sequence of operation to help diagnose it. Tape the door switch closed.
On a call for heat, Control module starts blinking, Inducer fan starts operating. A pressure switch closes allowing the Igniter to glow or light a small pilot. A few seconds later the gas valve will open allowing the main burner to ignite. The flame should spread to all burners and hit a small flame sensor. The flame should be dark blue with light blue tips. Some orange flicks at the flame tips may be seen. The flame should be steady and within 90 seconds, the room blower should turn on.

All of the above has to happen. Miss one step and you don't get heat.

I cannot believe that I found this on the internet! This is the Same thing I am going through. I do have the LED display, but when I go downstairs to check what is happening because I realize it is 60% in my house, the LED is not flashing at all. In other words, "All is Well". So, just as described above, I flip off and then on the power to the unit, and then I get an LED display code of "blower will run for 60 seconds if power is turned of during a call for heat" - or something very close to that.

The fan will kick on for the 60 seconds, then the gas begins and the pilot lights up bright and full, and then all of a sudden everything stops, the ignitor cools, the blower stops, and the LED goes back to solid (ALL is Well).

As with the first post, about 2 months ago, this would do the trick for a week or 2. It has slowly become more prevalent to the point where it is nearly every day. If I turn power off and on again, it may do the same thing, or I might get lucky and it turns on. Sometimes if I mess with the thermostat, it seems to help but I may just be imaging that piece... I can't confirm it. But, there has been at least one instance where although the actual room temp was way below the thermostat setting and the 'switch' inside was definitely tripped which should turn the heat on, it wasn't until I cranked the thermostat setting to as high as it would go that the heat came on. Or, I sometimes crank it down so that the switch trips back off, then crank it up all of the way, and I get lucky that way.

A definite pain and as with the first post, if I call someone in, I know I will be paying out of my you know what

Try this: remove thermostat, disconnect wires from "R" and "W" terminals, and connect them together. If the unit sustains operation, the problem is in the thermostat.

Quote:

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Originally Posted by KC13

Try this: remove thermostat, disconnect wires from "R" and "W" terminals, and connect them together. If the unit sustains operation, the problem is in the thermostat.

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Great... will try and see... fingers crossed - its cold here tonight :)