Had a fan wire to a two wire system

Old 07-06-18, 06:12 PM
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Want to add a fan wire to a two wire system

I have a Coleman/mix Honeywell furnace. Runs on two wires. Iím looking to add a fan wire to be operate off of nest.
The furnace has fan / limit control system Honeywell L4064B,
Heat system transformer, and the main two wires hook to a 3 way where two wire goes the HST then to the L4064B. Is there way I can add a g (fan) wire from nest. If so, where do I hook up to in the furnace?

Last edited by J2018; 07-06-18 at 06:31 PM. Reason: Errors
Old 07-06-18, 09:30 PM
Join Date: Jun 2012
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No simple solution without adding parts. Most of those furnaces with a fan/limit switch need to have a relay added to support fan control. A few offered an official a/c conversion kit that included a relay for fan control.

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