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JoeHEB1
Advanced Member
498 Posts |
 Posted - 11/16/2015 : 10:00:47 AM
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| Question, what makes the drier pop off? I have a 2009 IC Maxxforce 7 air drier popping off every 15 seconds. I've serviced the drier, replaced the drier relay on the firewall, replaced the air governor and still pops off every 15 seconds. WTH!!! Any thoughts? |
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tigger2
Advanced Member
USA
470 Posts |
Posted - 11/16/2015 : 10:58:37 AM
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| Check for air leaks in the line between the air governor and the drier pop off valve. This should be the center tap in the governor. |
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slippert
Top Member
USA
630 Posts |
Posted - 11/16/2015 : 11:00:16 AM
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| Normally losing pressure on signal line from governor to dryer, cause that... I had air fan drives on the DT's that would cause that to happen, as line for fan drive was tee'd into same line that fed dryer... problem can be hole in line, compressor unloader valves, purge valve, governor(which you already replaced) .. Every time compressor cuts out at full pressure governor sends air to dryer purge valve... if you have a leak /loss of air on that line it will make dryer cycle as compressor is constantly cutting in and cutting out.. even though pressure shows full in wet and dry tanks |
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exmod110
Senior Member
150 Posts |
Posted - 11/16/2015 : 11:18:46 AM
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if it is an ad-9 drier and it leaks through the purge valve after its initial main purge and doesn't stop till it is back on the build cycle check the check valve in the discharge port. If it is not seated it will allow pressure to bleed back out the purge valve in a constantly repetitive 10-30 sec cycle. it can be re-seated with a socket or something like that.
http://www.beamalarm.com/image/Air%20Dryer/Servicing/Bendix%20AD-9%20Air%20Dryer%20Servicing%204.jpg the check valve in pictured in the lower right corner. |
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aaronwilmoth80911
Top Member
538 Posts |
Posted - 11/16/2015 : 11:52:25 AM
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| On our 2010 DTs, we get a lot of leaks at the fan and at the fittings on the governor. |
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JoeHEB1
Advanced Member
498 Posts |
Posted - 11/16/2015 : 12:42:24 PM
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| When bus gets back from last route I'll check that line from the governor to the drier. I'll keep y'all posted. |
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JoeHEB1
Advanced Member
498 Posts |
Posted - 11/18/2015 : 04:11:36 AM
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| Found a leak at the fitting on the governor, fixed the leak but the problem remains. No other leaks were found. |
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57fan
Senior Member
United States
148 Posts |
Posted - 11/18/2015 : 9:46:54 PM
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| If you have a air operated fan clutch on the bus that is the first place I would look for a leak. AS for driers? They get there signal from the wet tank.. Put a gauge on the tank and monitor the air pressure. If it drops quickly then you have an air leak causing the issue. When the wet tank pressure drops below the cut in pressure it will cause the compressor to build until cut out pressure. then the drier will open the purge valve until the cut in pressure is reached again. |
Lead, Follow or get out of the way! Thomas Paine |
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JoeHEB1
Advanced Member
498 Posts |
Posted - 11/19/2015 : 04:08:34 AM
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quote:
Originally posted by 57fan
If you have a air operated fan clutch on the bus that is the first place I would look for a leak. AS for driers? They get there signal from the wet tank.. Put a gauge on the tank and monitor the air pressure. If it drops quickly then you have an air leak causing the issue. When the wet tank pressure drops below the cut in pressure it will cause the compressor to build until cut out pressure. then the drier will open the purge valve until the cut in pressure is reached again.
No air clutch, I'll gauge the wet tank and keep y'all posted. Thanks! |
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Topic |
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Bendix air drier popping off every 15 seconds
