York Diamond 80 blows cold air after blowing heat for 20 minutes

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Old 12-09-11, 12:45 AM
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York Diamond 80 blows cold air after blowing heat for 20 minutes

Hi experts,

I have a 14 years old York Diamond 80 furnace. Starting about 2 or 3 years ago, it blows heat for about 20 minutes and continue blowing room temperature air. Shut off the thermostat or any thing in the thermostat will not turn off furnace blower. When the furnace starts blowing cold air, it flash 8 in led. The only way to shut off the furnace is turned off power. Once the power is turned back on it will works fine if the set temparature is reached within 20 minutes. Otherwise, the same problem will appears again. I have clean flame sensor, changed flame sensor and roll-out switch. But the problem is still there. Filter is changed regularly.
I am in California and the temperature is not that cold. So I can turn off the furnace in thermostat to make sure the furnace does not blow more than 20 minutes a time as a work around. The only time that runs more than 20 minutes is in a cold morning and I do not really want to go into cold garage in the morning to reset power of furnace every morning. Would you please help me to diagnose and fix this problem?
Thanks in advance.
 
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Old 12-09-11, 02:19 AM
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Ummm. The list I have doesn't have a code for eight flashes on a York furnace. But perhaps your furnace is different.

Check that again, and look for a description of what the code represents, usually posted somewhere on the furnace, often on the back of the blower door cover.
 
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Old 12-09-11, 09:39 AM
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8 Red Ignition lockout due to recycles

I have cleaned and also replaced by a new flame sensor after reading

Code 8 after cleaning flame rod on York Diamond 80 furnace - JustAnswer

which is very similar to my problem. But it did not help.
 
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Old 12-09-11, 10:45 AM
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Well, presumably that diagnostic code is switched on when the furnace fails to detect that the main burner has lit, and has shut off the burners and attempted to relight the burners without getting that signal.

A flame sensor that needs cleaning is the most common cause of that problem, but there are others, including an ignition controlo that is failing and needs to be replaced.

What I'd do first is to take the cover off the burner compartment of the furnace and carefully observe what is happening when the furnace quits running properly. Turn the thermostat all the way up and check to see if the burners are shutting off and repeatedly trying to light the burners.

Are the burners lighting and being shut off after 3-5 seconds, or what?
 
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Old 12-10-11, 11:59 AM
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Thanks SeattlePioneer. I stay in the attic for a long time to observe from start of the furnace to it gets into problem. If set temperature is not reached, gas will be shut off for a few second in every 4 or 5 minutes interval, then ignition gets red and gas will coming and start burning again. After about 4 or 5 cycles, problem happens and gas shut off and the ignition is not turning red, no gas coming and blower is continue, so is the small motor for exhaust is also keep running. Because there no burning gas, cold air keeps blowing. I have to power off and on the furnace and everything goes back to normal.
If the set temperature is reached within 20 minutes the furnace will stop and everything work as normal and we can manually control this process in the morning either by furnace power or turn it off in the thermostat. Once it reaches set tempareture, will let the thermostat control the furnace and it works fine.
Is this a ignition control problem and how can I further isolate the problem?

Thanks for your help
 
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Old 12-10-11, 03:32 PM
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check on your control board or on the back of the blower door for a description of what code 8 means specifically for your furnace. Post that info here when you find it.
 
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Old 12-10-11, 04:34 PM
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8 Red Ignition lockout due to recycles

Here is the list of york codes Contractor: Furnace & Boiler Replacement & Repair Service

Thanks
 
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Old 12-10-11, 05:06 PM
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it sounds like there may be an overheating problem. This is due to the word Recycle instead of retry.
 
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Old 12-11-11, 04:47 PM
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Thanks hvactechfw. Do you have advise how do I find the culprit part of this problem?
 
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Old 12-11-11, 05:04 PM
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check filter, check evap coil to see if plugged up, Blower may be weak....Is it noisey on startup? Make sure ALL registers are open.
 
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Old 12-11-11, 06:09 PM
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Ummmm....


If the limit switch were opening I'd suppose you'd get:

4 Red Limit switch open



However, what the eight flash code is seems to be ambiguous to me:

7 Red Ignition lockout due to retries

8 Red Ignition lockout due to recycles



I'm supposing that means the module isn't detecting that the burner is lit.

Could be wrong, though.
 
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Old 12-19-11, 02:38 PM
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Hi,

I checked the evaporator coil and it is clean and only slightly dusted. None of my local hardware stores carry coil cleaner. So I vacumm it throughly. No difference that makes. The blower has no strange noise or anything like that and seem works fine.

Is there anything I can check to find the bad part?

Thanks,
Ming
 
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Old 12-19-11, 09:48 PM
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I'd use a voltmeter to check and verify that the burners are being shut off because the limit switch is opening. Probably it is --- but the diagnostic code is ambiguous and makes that worth checking.
 
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Old 12-31-11, 11:18 AM
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We are having the same EXACT issues as Ming-we don't know what a voltmeter is or what a limit switch is or where it's at. Also, how is the voltmeter used-that is, where do we check and verify whatever we are supposed to check and verify-what voltage is good and where would we get a voltmeter? Thanks in advance.
Also, we were wondering if it had to d with gas pressure because our gas fireplace also doesn't stay lit for long.
 
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Old 12-31-11, 12:14 PM
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we don't know what a voltmeter is or what a limit switch is or where it's at. Also, how is the voltmeter used-that is, where do we check and verify whatever we are supposed to check and verify-what voltage is good and where would we get a voltmeter?
You need to call a PRO. Be safe and do the right thing. If you dont know what it is or how to use it properly then call a PRO.
 
 

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