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Texasbill 10-30-2012 06:43 PM

Furance comes on then goes off after
Furance comes on then goes off after a few second started after I change the white rodgers 50M56U-843 control kit I have rheem furance about 10 years old..The air condition works fine.:(

Doc Holliday 10-30-2012 06:48 PM

Ground wire needs to be connected and tight for the flame sensor to properly sense micro amps. The furnace lights for about 3-5 seconds and then shuts off? The flame senor may also need to be cleaned. Use a scotch brite dish pad, the green ones.

how 10-30-2012 09:47 PM

If the fault diagnostic light on the 50M56U-843 is not showing you the problem then either it's faulty or you need to test your thermostat circuit. Turn off furnace power. Remove the stat wires in furnace from R & W and put a jumper between R & W and turn the power back on.
Let us know what happens.

Texasbill 10-31-2012 02:01 PM

It comes on then goes off
I jumper R&W the same thing it comes on then goes off and the air condition works fine ..

JJboy 10-31-2012 02:26 PM

Does the small fan turn on? the igniter glow??? how about flame at the burners?

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Texasbill 10-31-2012 03:01 PM

Comes on then goes out
yes they all turn on Fan ,glow plug,and the flame comes on at the burner on all three tubes.

JJboy 10-31-2012 04:48 PM

check ground, clean flame sensor.....can you take a picture of igniter

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Texasbill 10-31-2012 05:50 PM

Comes on goes out
1 Attachment(s)
Attachment 59792it is an universal nitride igintorit part number 21dD64-2 it was install at the time the 50M56U-843 was installed it came with the before the Air condition went out ,the furance was ok i had a bad control panel it was (burnt out) i changed the panel and now the furance will not work I will clean the flame senor and let you know,

Texasbill 10-31-2012 05:55 PM

come on goes off
1 Attachment(s)
Here is the panel connections

JJboy 10-31-2012 07:28 PM

Even if the igniter glows it doesn't mean it will be hot enough to light the gas....I would check the voltage across the connector first....check the resistance also.... replace the igniter......

ben's plumbing 10-31-2012 08:03 PM

do you have a flame sensor on your furnace...I did not see one...that kit the w/r 50m56u-843 I believe requires you add a flame sensor for rheem furnaces...check instructions i could be wrong..ben sr

how 10-31-2012 08:27 PM

Board diagnostic's not working.
Replace board.

Texasbill 10-31-2012 09:35 PM

Comes on and flame out
2 Attachment(s)
The start up is normal will not stay lit has a nice blue flame flames then goes out ,yes there is a flame senor. I may have not gave the correct problem with the unit I hope this help.

JJboy 10-31-2012 09:40 PM

if you have a multimeter with DC miliamp, connect the meter in serie with the flame sensor. the measure should be 2.0 - 4.5milliamp

ben's plumbing 10-31-2012 10:25 PM

looks like you could clean that sensor ....worth a try...

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