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View Full Version : Trying to figure out honeywell rth7400


jasonjaj26
Feb 19, 2009, 06:16 AM
Ok I have way too much info to confuse someone so here we go.
I have an old amana therm. Not sure which numbers are the model number so I'll list them all.
(Q674F 1022)
(T874C 1059)
class 2 30V max LR1620
here is how it was wired

brown---x2 out side went to 2 browns one to defrost board and one to heater coils

white---w1> out side white and yellow together wire to a yellow that goes to defrost board
yellow--y1> " " " " "

blue---w2 out side goes to 2 whites & a purple. 1 white an purple goes to heat strips and other white goes to defrost board.

green---g out side green goes to fan relay

red---r out side red goes to defrost board

orange---o out side orange goes to defrost board

new therm. Is honeywell RTH7400
options are

C
G
Y
O/B
RC JUMPED WITH R
AUX
E
L

I wired it they way I thought it would work and it seemed like the a/c worked fine
but it didn't want to work with heater ?

the way I did was
C=BLUE
G=GREEN
Y=YELLOW
O/B=ORANGE
R=RED
AUX=BROWN
E=WHITE

THIS IS THE PAYNE UNIT I HAVE OUTSIDE www.docs.hvacpartners.com/idc/groups/public/documents/techlit/im-ph1z-03.pdf

hvac1000
Feb 19, 2009, 06:36 AM
https://www.askmehelpdesk.com/heating-air-conditioning/amana-thermostate-rewire-honeywell-314622.html

This might help you out some

jasonjaj26
Feb 19, 2009, 06:52 AM
That was my previous post before I found out that the wires to the back of the thermostat wasn't going straight to the heat pump. Apparently when the old outside unit was replaced they just spliced some wires together to make it work some of the wires that are on the old therm. Aren't even hooked up outside. Now I'm left to try and figure out what they did. That's why I need someone to look at the information I have gathered so far and tell me what color wire needs to go to which letter on the back of the new thermostat

hvac1000
Feb 19, 2009, 07:41 AM
You will need to post the Exact color to Exactly where that wire goes on the equipment. Then the thermostat might be able to be figured out.

jasonjaj26
Feb 19, 2009, 07:44 AM
brown---x2 out side went to 2 browns one to defrost board and one to heater coils

white---w1> out side white and yellow together wire to a yellow that goes to defrost board
yellow--y1> " " " " "

blue---w2 out side goes to 2 whites & a purple. 1 white an purple goes to heat strips and other white goes to defrost board.

green---g out side green goes to fan relay

red---r out side red goes to defrost board

orange---o out side orange goes to defrost board

hvac1000
Feb 19, 2009, 09:20 AM
Take a look at this change over sheet. It should cover just about all the situations in combination with the diagram of the unit you provided and the new thermostat wiring diagram.

hvac1000
Feb 19, 2009, 09:22 AM
Note you will also have to run the setup on the new thermostat so that O is used for defrost.

jasonjaj26
Feb 19, 2009, 10:13 AM
Thanks that helps a good bit. The only two that I can't seem to figure out is which color white or brown should go to emer.heat (e)and then I guess the other would go to aux. heat (w2) how do I find out which one (white or brown) goes to emerg. Heat and which one goes to Aux. heat?

Mikie D
Mar 13, 2009, 05:25 PM
Put the white wire on aux heat and see if reversing valve denergizes so it goes into heat pump mode or vise versa see if the electric heat back up pulls in it can only be one or the other especially if a/c works but normally A/C only kicks in when reversing valve is energized.Mikie D