York 80 Diamond doesnt fire up


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Old 12-01-11, 03:04 PM
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York 80 Diamond doesnt fire up

Greetings,

I have a York 80 diamond that isnt working correctly. It gives me 7 flash error indicating an ignition lockout.

I call for heat, inducer comes on, HSI glows bright red, click then hsi fades. Repeats until error code. At some point during this the main blower comes on. Nothing fires up.

Im thinking this may be a (white-rodgers) gas valve issue not allowing the gas to flow over the HSI to ignite.

I havent checked for 24v to valve (will when i get home), but is there any other ways of checking the valve to isolate problem?

In troubleshooting--ive read alot that the 7flashes usually indicated a flame sensor. Is my thinking correct that the error is a step BEFORE the flame sensor even comes into play? (in other words, im reading that the sensor is suppose to detect the gas-fire and not the heat from the HSI)
 
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Old 12-01-11, 03:57 PM
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The flame sensor detects FLAME not heat. An AC voltage is applied to the flame sensor and when flame engulfs the flame sensor a small DC current flows which is detected by the ignition module.

What should happen in your furnace is that the hot surface ignitor gets white hot, the gas valve is switched on and gas from the gas valve ignites. The flame sensor would verify that the burners lit, and the gas would therefore be left on.

If I am understanding your description correctly, the HSI is heating up but no gas comes from the gas valve.

1. check to be sure all the gas valves to the furnace are on and that the valve on the electric gas valve is switched on.

Is this natural gas or propane? Do you have other gas appliances, and if so are they operating normally?

2. Use an AC voltmeter across the wire to the electric gas valve to see if you have 24 VAC being switched on to the gas valve after the HSI heats up.
 
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Old 12-01-11, 03:58 PM
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if no flame at all then it cant be the flame sensor. You need to check voltage at the gas valve shortly after the HSI glows. If voltage then you need to make sure you have gas at the furnace.
 
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Old 12-02-11, 07:54 AM
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I get the 24vac to the gas valve. Im leaning towards the gas valve being the problem(and i can find a replacement for under 100).

It is natural gas and the water heater, gas fireplace etc work fine.

I was just making sure my thinking was correct about the flame sensor and that it had no affect on whether the gas valve was to open up.

Ill repost my progress to hopefully help others with similar problems.

btw: here's an edited version of my wiring schematics of the york 80 for others--ive added some notes, pics, and colored in some wires as i researched my problem.






Link: ImageShackŪ]ImageShackŪ - Online Photo and Video Hosting - Online Photo and Video Hosting
 

Last edited by trancers21; 12-02-11 at 08:00 AM. Reason: added image
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Old 12-02-11, 10:02 AM
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If you have the 24 VAC being switched on to the gas valve, the gas should turn on. Check to be sure the valve at the furnace and the electric gas valve are on. If it were me, I'd open the gas piping at the furnace to verify that you have gas.

And I'd check for electrical continuity across the gas valve to see if you can verify that the gas valve is burned out.

I recommend against DIY replacement of electric gas valves. Improper installation can damage the furnace and create real safety hazards.
 
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Old 12-05-11, 08:28 AM
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Turned out to be one of the limit switches. When i got up to the furnace on Sat to check voltage, it turned out that the gas valve did get 24vac after the HSI fired up. From there I began checking voltage on each switches. There were 2 that were actually on the control panel side of the furnace with both having red and yellow wires to them.

I reset the switches (theres a button in the middle of the switch between the 2 wires) and the furnace fired right up.

The r/y wires i had taken off to take off the main blower fan--which was the original problem (i replaced the squirrel cage when it broke off the motor shaft). I guess somehow the switch stuck? when i removed the wires.
 
 

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