Honeywell fan limit control, old has 6 wires new has 4


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Old 10-26-13, 01:28 PM
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Honeywell fan limit control, old has 6 wires new has 4

Hi, switching out a very old honeywell fan limit control that has 6 wires, 2 extra wires coming out of from inside of housing. The new one has 4, Any idea what the 2 extra wires are for and what to do with them now. There is another post on same topic, but no answers, Please help. Scmatic is not on old unit. I've read plenty of schematics online, so please answer only if you really know or know a way to find out. Like to get it on this weekend before calling tech and save mom a few $$.

Gas, hot air furnace. Thanks
 
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Old 10-27-13, 09:41 AM
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Without a make and model of the furnace it could be pretty tough to help you.

The norm is a four wire switch and someone added in two wires to run an electronic air cleaner or humidifier.
 
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Old 10-27-13, 01:31 PM
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Additional 2 wires are probably for a pre-heater. The furnace manufacturer put that type of control on to bring the fan on a little quicker. If the furnace is downflow or horizontal I wouldn't switch to a 4 wire fan/limit. There should be a number (L4064) followed by a letter, & a 4 digit number on the old control. The letter after the L4064 is important as is the last 4 digit number. The last 4 digits include a length code.
 
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Old 10-28-13, 01:29 PM
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The model of the old "combination fan and limit control"s Honeywell L4064 T 1970. This has an extra set of spade terminals right in the middle.
I called Honeywell they had no clue, too old. I installed new control and left wires unattached. In case pic doesn't come up, they went to the gas valve terminals C and M.

Weather king on cover, inside tag Addison mfg model GDWHE20AD5
 
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Old 10-28-13, 01:44 PM
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The new control only has four terminals and you just taped off the extra two wires that went to C and M ?

Is Addison the gas valve ? I couldn't find that part number listed.
 
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Old 10-28-13, 01:59 PM
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[ATTACH=CONFIG]20091[/ATTACH]Addison is the mfg of unit, trying to upload a pic, but lost.. If anyone knows how to post a pic would sure help. Seems I do not have the "add picture" features enabled.
 
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Last edited by surfmaster911; 10-28-13 at 02:57 PM.
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Old 10-28-13, 02:32 PM
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Here's a thread on how to post photos: http://www.doityourself.com/forum/ga...st-photos.html
 
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Old 10-28-13, 02:58 PM
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To Grady, thanks for the pic tip..
 
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Old 10-28-13, 05:44 PM
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You're welcome. I would set the fan on switch to no more than 130*, maybe even 120*, especially if the furnace is either down flow or horizontal. If you aren't sure what the air flow configuration is here's how to tell: If the circulating fan is on top, it is set up for downflow; if the fan is on the bottom, the furnace is upflow. Horizontal is pretty much self expanitory.
 
 

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