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-   -   Ignitor glows brightly and shuts down or glows dim and sometimes works (http://www.diychatroom.com/f17/ignitor-glows-brightly-shuts-down-glows-dim-sometimes-works-131200/)

pumpkin321 01-24-2012 02:31 AM

Ignitor glows brightly and shuts down or glows dim and sometimes works
 
I have and American Standard Model #AUD1B080A9481AA. Problem #1 unit calls for heat, inducer motor comes on, ignitor glows brightly for 4 to 5 seconds, inducer motor goes off and blower comes on. Diagnostic code said to check flame igniter. I replaced flame igniter. After I replaced igniter another issue came up which I will call Problem #2. Furnace only workes about 80% of the time. 20% of the time there is a call for heat, inducer motor comes on, igniter glows dimly, gas hisses, but burners do not light and gas and igniter both go off. It will do this a few time, sometimes burners come on and sometimes not. Furnace then goes back to Problem #1 for about half a day and then back again to Problem #2 (works well 80% of the time). Unit currently is going back and forth from Problem #1 and Problem #2. During problem #1 I get a 120 volt reading where ignitor is wired, but during problem #2 I only get a 70 volt reading.
Inducer motor sensor is not clogged, I cleaned flame sensor, and safety switches all seem to be working OK. Ignitor, control board, and pressure switch have all been replaced. Help.

plummen 01-24-2012 07:28 AM

Gas valve? :)

Tator1076 01-24-2012 09:39 AM

Burners maybe dirty or Ignitor is not inline with burner

pumpkin321 01-24-2012 01:03 PM

ignitor sometimes is bright and sometimes not
 
I think burners wont come on because ignitor is not hot enough, but I don't know why it sometimes gets hot and sometimes not. But when it gets hot unit locks out.

yuri 01-24-2012 01:33 PM

check the furnace grounding. should have O ohms between the ground from the furnace and the board mounting plate to a copper water line, use a cheater wire if necessary. check from C on the board to the neutral wire to the furnace with a volt meter with the power on and door switch pressed in with duct tape, should be 0 or less than .5 volts. if poorly grounded the board will malfunction.

harleyrider 01-24-2012 02:12 PM

Quote:

Originally Posted by pumpkin321 (Post 832977)
I have and American Standard Model #AUD1B080A9481AA. Problem #1 unit calls for heat, inducer motor comes on, ignitor glows brightly for 4 to 5 seconds, inducer motor goes off and blower comes on. Diagnostic code said to check flame igniter. I replaced flame igniter. After I replaced igniter another issue came up which I will call Problem #2. Furnace only workes about 80% of the time. 20% of the time there is a call for heat, inducer motor comes on, igniter glows dimly, gas hisses, but burners do not light and gas and igniter both go off. It will do this a few time, sometimes burners come on and sometimes not. Furnace then goes back to Problem #1 for about half a day and then back again to Problem #2 (works well 80% of the time). Unit currently is going back and forth from Problem #1 and Problem #2. During problem #1 I get a 120 volt reading where ignitor is wired, but during problem #2 I only get a 70 volt reading.
Inducer motor sensor is not clogged, I cleaned flame sensor, and safety switches all seem to be working OK. Ignitor, control board, and pressure switch have all been replaced. Help.

sounds like a bad board, or a bad gas valve......

hvac5646 01-24-2012 03:03 PM

Hes only getting 70 volts. Could be a bad board or a bad supply voltage connection.

seen a lot of that when the neutral wire connection is loose.

How do yoou guys figure a bad gas valve with 70 volts at igniter but no voltage reading posted for the valve ?.

plummen 01-24-2012 06:06 PM

I didnt see the 70 volts part,yeah check neutrals first :)

pumpkin321 01-24-2012 07:55 PM

ignitor sometimes bright sometimes not
 
As you suggested I checked grounding, everything ok except ohms are very irratic (242 to 1) when contacting copper water line only. Also, end of wire (Green) that is wrapped around copper line is not connected to anything on furnace side (cannot see other side - in the attic). This cord (wrapped around copper tube) has 3 wires (red, green, and white). White goes to thermostat, Red goes to "Y", and Green is not attached to anything. Error code is 9 which says check ignitor and line "N" to 24VAC "Common" voltage [possible grounding problem].

Tator1076 01-24-2012 09:04 PM

"Green is not attached to anything".Green should be to ground. Green is color coded for ground. Wire it some were to metal. Most the time on one of the screws hold burner cross bar

harleyrider 01-24-2012 10:37 PM

Quote:

Originally Posted by hvac5646 (Post 833411)
Hes only getting 70 volts. Could be a bad board or a bad supply voltage connection.

seen a lot of that when the neutral wire connection is loose.

How do yoou guys figure a bad gas valve with 70 volts at igniter but no voltage reading posted for the valve ?.

thats all it takes for a trane or american standard ignitor to energize...........the boards vary the voltage to the ignitor, sending only whats needed to get the job done.sonds like the valve may be causing a voltage drop from a internal short.

Baldrick 01-25-2012 02:18 AM

Been there and done this too many times, you are right that the board uses a logarithm to regulate how much power goes to the ignitor. If the ignitor is not lighing up and the gas is coming on it is for sure a board issue. The gas valve should not energize with no source of ignition. If the ignitor is glowing but not igniting the gas then I would say the gas is not hitting the ignitor either something in the burner blocked or incorrect positioning of the ignitor. Could be a bad ignitor but I doubt it.

hvac5646 01-25-2012 08:58 AM

Quote:

Originally Posted by harleyrider (Post 833894)
thats all it takes for a trane or american standard ignitor to energize...........the boards vary the voltage to the ignitor, sending only whats needed to get the job done.sonds like the valve may be causing a voltage drop from a internal short.

HHMM.. I don't get much work on AS or Trane. The dealers pretty much have that sown up around here.

My Nordyne brands varies the voltage too, but they don't go to 70 volts as a normal part of the voltage variance.

But thanks for that input it's appreciated.:thumbsup:

Baldrick 01-25-2012 10:43 AM

American Standard Nitride ignitors are only rated for 80volts and less on some models. Put one of these in a regular 120v and they only work for about 2 cycles. LOL:yes:


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