No heat from furnace


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Old 12-29-08, 11:17 AM
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No heat from furnace

When the thermostat calls for heat the furnace kicks on, the draft motor starts and i hear a seperate click (im guessing this is the pilot trying to light), and i smell a tiny bit of gas. The click and the gas smell repeats every 30seconds or so but it does it more than 3 times in a row(i read that its supposed to lockout for a while after 3 failed attempts). it has a White-Rodgers 50e47-140 ignition pack and upon powering on the furnace the led light glows red for about 2 seconds but never again after that. I'm guessing that maybe i should take a look at the flame sensor, does that sound like my best bet? Any other ideas/tips are greatly appreciated.
 
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Old 12-29-08, 11:24 AM
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You need to take the cover off the furnace and observe carefully what is happening. You don't have a pilot with that control, you have a hot surface ignitor which you should see glow white hot. Then the gas valve should click on and the gas should be lit by the HSI.

It sounds like the HSI is probably burned out. Usually you can see a crack in it with a fringe of a whitish powder if you remove the HSI.

If so, it needs to be replaced.
 
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Old 12-29-08, 11:53 AM
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please forgive me, as im not too familiar with much of this. is the HSI on the other side of the wires i pointed to in the picture?
its behind a panel that was sealed, is there a special type of hi-temp caulk/sealer i need before i open it up? there is a small window at the bottom of the panel(about 1x2 inches), i peeked in there with a flashlight but could see no activity inside.

Thanks
 
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Old 12-29-08, 01:11 PM
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I think where it actually is is just out of the picture. Below the picture. Yes, your arrow points toward the wires for it.

On your control module you have 2 black wires at the top of it in one jack. That likely incoming line voltage and HSI together. Then at the HSI it returns through the white wire at your arrow.

I have a feeling that out of the picture, below the photo, are the screws to the cover for the combustion chamber. You will have to access that by removing those screws to get at the HSI.

Before you do, do two things first:

1. Unplug the 2-black wires jack from module and I think you will find instead of spades - split pin connections. Use a thin knife and open those spits a tad to enlarge the pins diameters. You have the same looking module I recently had where opening those pin connectors fixed the furnace for me!!

2. You could turn off the furnace and unplug that 2-black wire jack and do ohms test between a black wire and the return white wire. Test between black IGN wire and white wire. Not black LINE wire. If you get no reading, then you can rest assured the HSI is burned per Seatle's description.
 
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Old 12-29-08, 01:20 PM
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That looks like an Arco Air brand furnace --- or at least that's one of the brand names for this furnace.

Yes, take the screws out of the front cover to get access to the burners and hot surface ignitor. You are probably going to find it needs to be replaced.

The furnace burners on this furnace should be taken out and cleaned with a wire brush every couple of years or you risk getting the furnace plugged with soot.

Also, there are baffles that need to be removed after you remove that cover plate. Pay careful attention to how you remove them or you will find it difficult to reinstall them correctly.

Use your camera and take pictures of the parts as you remove them, and pay attention to how they fit back in.
 
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Old 12-29-08, 01:39 PM
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thanks guys



Thanks guys, it was the HSI. didn't know if i shoulda taken off that panel, it was stuck on there pretty good. also cleaned off the flame sensor and vacuumed while i was in there, after putting the panel back on and firing it up i could notice the HSI glowing hot through that small window... it was hard to miss, wasnt glowing like that before for sure. yay for $30 repairs!

thanks againBeer 4U2
 
 

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