On Mon, 18 Feb 2008 19:03:00 -0600, CJT wrote:

mr. spam wrote:

i have an old furnasman gas furnace.

It has AC

there is a honeywell transformer screwed on to the electrical connection
enclosure i suspect it was installed when the ac was installed.

I want to replace the fan motor with a 2 speed one

i want to add a switch to the furnace so i can have the fan on all the
time in slow speed. then when the burner or the ac comes on it will
change to high speed.

is there a relay i can install to do this or is there something else i
need to do.


I think many (most? all?) furnace/AC combinations already incorporate
dual speed fans. Are you sure it doesn't already have the capability
you seek? You might just need an appropriate thermostat.

My furnace has a 2-speed fan, although it isn't switched the same way
as the OP wanted. Low speed for heat. High speed for A/C or manual.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"How could you ask me to believe in God when there's
absolutely no evidence that I can see?" -- Jodie Foster