Coleman DGAE080CDK making noise, takes a long time to start

[WildIrish]

We have a Coleman DGAE080CDK (serial no. W0F6557001). Over the past year, it seems to be taking longer and longer to start. We've had technicians out here twice, but I'm not sure they know what they're doing. So I'd like some advice to see whether my hunch is right or wrong.

Now, it's not just that the start-up time is longer, the furnace is also making some odd rattling noises as it starts up.

I recorded the sound, and uploaded it in mp3 form. The "full version" includes the 58 seconds it takes for the furnace to kick in, after we hear it trying to start.

Furnace (full version):
http://www.mediafire.com/?e0gckml5dvm

The short version is for people on dial-up. It only includes the sound of the furnace actually starting to blow air.

Furnace (short version):
http://www.mediafire.com/?nyc01zmyjny

The sound is much louder than the recording. It wakes us up at night, and it's something that just started recently.


Any idea of what this might be? I'm going to call another furnace repair company, but I want to have some idea of what's going on...so that I'll understand what the repairman's talking about when he gets here.


Thanks!

[Mark]

Hi,

Sorry for the slow response. Guess we needed to find a minute to figure out how the sound bit files worked. But I got them working. Here's what it sounds like is happening to me.

When the furnace first starts, the booster motor comes on. That I can here. Once it brings the burner chamber up to pressure, it trips a pressure switch. This starts the lighting process of the burners. If the burners light and go right out, it'll try again. After so many times, it may quit trying. If it is trying to light, and goes out, and tries again, you then need to clean or replace the flame sensor. I mention this because it could be one reason it's taking longer and longer for your furnace to start-up.

Once the burners are lit, then the blower motor will kick in after so many seconds. This is the noise I hear in your sound bite. The blower wheel is either out of balanced or rubbing on the cage or something. The blower assembly should be inspected.

For a semi-competent hvac tech, this is all basic stuff. But I understand there's a lot of non-competent techs out there.

Mark

[WildIrish]

Here's what it sounds like is happening to me.

When the furnace first starts, the booster motor comes on. That I can here. Once it brings the burner chamber up to pressure, it trips a pressure switch. This starts the lighting process of the burners. If the burners light and go right out, it'll try again. After so many times, it may quit trying. If it is trying to light, and goes out, and tries again, you then need to clean or replace the flame sensor. I mention this because it could be one reason it's taking longer and longer for your furnace to start-up.

Sounds like our furnace repairman doesn't know too much, because we had been complaining about the furnace taking longer and longer to start. I *thought* we had reason to worry about it!

Once the burners are lit, then the blower motor will kick in after so many seconds. This is the noise I hear in your sound bite. The blower wheel is either out of balanced or rubbing on the cage or something. The blower assembly should be inspected.

I'll print out what you've posted, and show it to the next repairman who comes out here.

For a semi-competent hvac tech, this is all basic stuff. But I understand there's a lot of non-competent techs out there.

You can say that again!

Thanks for your help,
WildIrish

Mark[/quote]