Honeywell T841A1670 to RTH7400D1008 - http://www.hvacmechanic.com/ Forums

Original message

ColorBlind

24.110.105.205

"Honeywell T841A1670 to RTH7400D1008" , posted Sun 23 Sep 19:37

OK, so I have been reading the posts and still have a question about the conversion/upgrade from a Honeywell "Analog" T841A1670 to the "Digital" RTH7400D1008.
My system is a AC/Heat w/Heat Pump (Trane TWE042C14FB1).

The T841 was wired as:

Orange to O
Yellow to Y
Green to G
Red to R
Blue to B
Tan/Brown to T
White to W jumped to X2
U and F connections open

The RTH7400 has

C
G
Y
O/B
Rc
R
Aux
E
L

I am making some assumptions that:

C = ???
G = Green
Y = Yellow
O/B = Blue
Rc = Jumper to R
R = Red
Aux = ???
E = ???
L = ???

I still have a White / Brown or Tan / Orange wires to try and figure out the configuration.

Would be nice if a guy could find the wiring diagram from the old unit and just match it up the diagram for the new unit, but that would make WAY to much sense... lol

Thanks.

RHuskey

Replies:

Houston204

98.196.66.53

"Re(1):Honeywell T841A1670 to RTH7400D1008" , posted Sun 23 Sep 20:14

New terminal = wire
C = blue
G = green
Y = yellow
O/B = orange
Rc & R = red (use jumper)
Aux and E = white (use jumper)

Tape off tan

set option 170 to 7
set option 190 to 0

"Tip of the Day" Remember to remove power first.

ColorBlind

24.110.105.205

"Re(2):Honeywell T841A1670 to RTH7400D1008" , posted Mon 24 Sep 18:05

Thanks for the response and EXCELLENT diagram. Tried this option out last night and everything seems to be working great.

Huge help and VERY much appreciated.

Now if only someone like Honeywell could offer the same help... lol.

Take care and thanks again.

RHuskey