Adding fan only to Hot air heating system.


Hi we have a oil fired hot air system that when you turn up the thermostat the heat blows thru the vents. What I would like to do is replace the existing thermostat with one that has a fan only setting as well. Is the wiring for this complicated ? Are there any diagrams available ?
Thanks
Ed
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Ed wrote:

Unless the furnace already has a Fan relay (24V relay), you can't do it without substantial re-wiring of the furnace controls.
If it was built as "ready for air conditioning" it will have a relay. Check the diagram on the unit.
Jim
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Can be.
I don't know.
Many heat only furnace switch the fan with a fan limit switch. You may need to put in an auxiliary relay. I did a system one time, we added AC to a house with a heat only furnace. I had to do some rewiring to get the fan to come on with the AC.
Since you have to ask the question, you probably don't presently ahve the skills.
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Christopher A. Young
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