Bryant / Day & Night / Payne 376C Downflow Furnace...

[kbanas]

Hello!

I posted a question about my furnace over at Metafilter.com, and one of the fine folks there recommended I come with it here if I hoped to find an answer, so, I here I am!

I'll repost my comments from there to here: 

I don't know things about furnaces. I have the the user manual here, and best I can figure it's a Model 376C Downflow Horizontal Furnace from Bryant / Day & Night / Payne. It operates on natural gas.  Other gas appliances in the house, like the oven, function normally.  The manual opens by welcoming me to a new generation of comfort, and I must say, based on my current level of cold, I find this suspect.

So, things that I know / have done follow:

This is a furnace with an electronic ignition. It doesn't have the pilot light like the furnace we had when I was a kid. Instead, the pilot light appears to be a filament. The furnace turns on and the fan runs, and when the thermostat is activated, the pilot light (which is located behind the 'gas burners') clicks on with a welcoming orange glow.

As I understand it, after this happens then the main burner should activate with a gratifying "Fwooosh." However, it does not. Instead, the pilot 'light' stays on for a couple seconds, and then powers down. It then attempts to activate and light the main burner twice more. After it fails at these attempts, the furnace goes into a "lock down" mode, where it will not function again until I turn it off and turn it back on.

I have put in new filters. This has had no effect. I have tried turning off the gas valve, turning off the gas valve control knob, cutting power to the unit, and then letting it sit for ten minutes before restarting it. This has had no effect. I have tried cleaning out the relief box and the gas burner with compressed air, based on something I read in the manual. This has had no effect.

So, barring that, is there a "fix me" switch or some other maintenance step I might perform that will not blow me up but might resolve this issue? Or, ok, maybe not resolve it, but might point me down the right path?

Thank you for your time.

[appl.tech.29501]

I'm not a heating and air guy, but here's some things to check

check the connector at the main board for a secure fit once verified, check voltage at the gas valve when the ignitor lites...not sure what the voltage should be, but if you have voltage then most likely your valve is bad, if you don't have voltage most like your board is bad.

do you have a digital or mercury thermostat?

[kbanas]

I don't mean to sound like a total doof, but I'm not sure as to the nature of the thermostat.  I mean, it's not digital - I've seen fancy numbers where you can program different temperatures based on time, etc, etc - this is not that - it's just a dome on the wall with a dial that points to where you want the temperature to be and a little dot that shows you what the temperature actually *is*.  So, I mean, that's not digital, but it's also not mercury in the way that I think about mercury - maybe it has an internal mercury component.

When you say to check the voltage on the gas valve - you mean like with a multimeter or some such?  And, like, where?  I mean, the gas line has a a couple of components - there's a red 'open/close' valve, there's a 'on/off' knob for the gas on the furnace itself, and then there look to be three places where the gas line empties into the 'gas burners'...

Oy.. I'm over my head..!

[dkpd1581]

Lets start with some of the very basics:

1. is the gas meter pinned closed by the gas company or is it open?

2. is the gas cock on the gas line before he unit open/on?

3. have you bled the gas line of any air?

4. after the hot surface ignitor glows red, do you hear any clicking sound from the gas valve or can you place your hand on it and feel it click to open and close?

5. have you looked inside the cabinet where the gas valve is to see if there are any small penny sized switches with one wire in and one wire out that have the little reset button on them.  If so, press it and feel for a click indicating it was tripped

Barring these simple fixes you will need a multimeter and some basic understandings of electricity.  If not, you might be best to get someone who does to help out with further explanations.