Hooking Up New Thermostat. Just Need Some Clarification - HVAC - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 10-31-2011, 11:47 PM   #1
Newbie
 
Join Date: Oct 2011
Posts: 18
Rewards Points: 10
Default

Hooking up new thermostat. Just need some clarification


Hi All,
I bought a new thermostat that has a separate controller that’s mounted near the HVAC equipment. Its not a complex system just a FAG furnace and A/C. There are 3 wires between the thermostat and the controller which is self explanatory. The other issue I have is the hookup from the controller to the furnace. I think I have it right but don’t want to guess since I can’t afford a new furnace

Anyway the markings on the furnace are as follows,
Y - Blue wire
G - Green wire
W - White wire
R - Red wire
C - White wire

The wires on the old thermostat are as follows,
Y – Blue wire
G - Green wire
W - White wire
RC - Red wire (there is a jumper installed to R)

I attached a schematic of the new controller. My plan was to disconnect the wires from the furnace, put the controller inline and distribute to the correct terminals.

So,
D1, R-2,C-3 will connect the thermostat to the controller.

Y-White wire
G-Green Wire
W1 (O/B)-white wire (this looked most correct)
R,RC,RH-Red wire. My question is there are jumpers across all three terminals. Do I leave those installed or take them out? Leave some and not others? Not too sure on that.
C- Goes directly to the A/C unit so its not really a component of this install.

If I had two dimes to rub together I'd hire someone but unfortunately for me I can't. Thanks for all the help.

J


Advertisement

cruzmisl is offline   Reply With Quote
Old 11-01-2011, 04:47 AM   #2
Member
 
Join Date: Oct 2011
Location: North Carolina
Posts: 205
Rewards Points: 150
Default

Hooking up new thermostat. Just need some clarification


The equipment module will wire to the equipment just like a t-stat. match up the y,R,w,G terminals to the controller just like you would a t-stat.

Advertisement

Patrick Eubanks is offline   Reply With Quote
Old 11-01-2011, 09:17 AM   #3
Newbie
 
Join Date: Oct 2011
Posts: 18
Rewards Points: 10
Default

Hooking up new thermostat. Just need some clarification


That's what I thought. So leave all the R, RH, RC jumpers installed?
cruzmisl is offline   Reply With Quote
Old 11-01-2011, 09:57 AM   #4
Member
 
Join Date: Oct 2011
Location: North Carolina
Posts: 205
Rewards Points: 150
Default

Hooking up new thermostat. Just need some clarification


yes leave them installed
Patrick Eubanks is offline   Reply With Quote
Old 11-02-2011, 09:11 PM   #5
Newbie
 
Join Date: Oct 2011
Posts: 18
Rewards Points: 10
Default

Hooking up new thermostat. Just need some clarification


Ok thanks a ton. I hooked everything up but nothing works. Thermostat is dead and LED's of the EIM module didn't come on when I applied power. Its like it doesn't have power which had me looking at the schematics again and I came across another variant of the original.

I noticed between C and R shows 24V. Is that an external transformer I need to tap 24V from? If so is it a wall wart type transformer or do I pull it from a transformer in the furnace? Am I on the right track?

Thanks!
J.

cruzmisl is offline   Reply With Quote
Old 11-02-2011, 09:36 PM   #6
Member
 
Join Date: Aug 2011
Posts: 729
Rewards Points: 500
Default

Hooking up new thermostat. Just need some clarification


You need to pull from the transformer in the furnace.
Master of Cold is offline   Reply With Quote
Old 11-02-2011, 09:39 PM   #7
Member
 
Join Date: Aug 2011
Posts: 729
Rewards Points: 500
Default

Hooking up new thermostat. Just need some clarification


Make sure you have the correct white wire. According to your original post you have 2 of them. Ohm the white wire and the yellow. The white one that you get 15-20 ohms across is going to be the "c" wire. The other is the "w".
Master of Cold is offline   Reply With Quote
Old 11-02-2011, 09:51 PM   #8
Newbie
 
Join Date: Oct 2011
Posts: 18
Rewards Points: 10
Default

Hooking up new thermostat. Just need some clarification


Thanks! The furnace has two white wires but the one white wire goes out to the A/C unit so I didn't touch it. It also didn't connect to the thermostat.

I get 28V across the white wire and C and R. Is that normal?

I don't have a yellow wire in my system brother. Did you mean a different wire? I'll double check the resistance just to be sure. I'll take a look inside the furnace for the transformer. Will there be an easy hookup or will I need to tap into the existing wiring?

I truly appreciate the help

Here is a pic of the hookup inside the furnace. You can see the "extra" white wire is connected to "C" and the pairing black wire connects to "Y" but as I said neither connects to the thermostat.


Last edited by cruzmisl; 11-02-2011 at 09:59 PM.
cruzmisl is offline   Reply With Quote
Old 11-02-2011, 10:12 PM   #9
Member
 
Join Date: Aug 2011
Posts: 729
Rewards Points: 500
Default

Hooking up new thermostat. Just need some clarification


Put the red wire on the rh/rc, and the white on the c
Master of Cold is offline   Reply With Quote
The Following User Says Thank You to Master of Cold For This Useful Post:
cruzmisl (11-02-2011)
Old 11-02-2011, 10:13 PM   #10
Newbie
 
Join Date: Oct 2011
Posts: 18
Rewards Points: 10
Default

Hooking up new thermostat. Just need some clarification


Leave all the jumpers in place too? Red wire is already on R, RC and RH. They're all jumped together

Last edited by cruzmisl; 11-02-2011 at 10:16 PM.
cruzmisl is offline   Reply With Quote
Old 11-02-2011, 10:34 PM   #11
Member
 
Join Date: Aug 2011
Posts: 729
Rewards Points: 500
Default

Hooking up new thermostat. Just need some clarification


Yes.
You need the common and hot from the transformer hooked up.
Master of Cold is offline   Reply With Quote
Old 11-02-2011, 10:52 PM   #12
Newbie
 
Join Date: Oct 2011
Posts: 18
Rewards Points: 10
Default

Hooking up new thermostat. Just need some clarification


OK partial success. Thermostat is on, fan works but heat won't turn on. Do I need a wire hooked up to W1 cause I took the white wire off that and put it on C. When I tried cool it turned on the fan but the thermostat went dead so I shut it all down.

Last edited by cruzmisl; 11-02-2011 at 11:00 PM.
cruzmisl is offline   Reply With Quote
Old 11-02-2011, 11:51 PM   #13
Member
 
Join Date: Aug 2011
Posts: 729
Rewards Points: 500
Default

Hooking up new thermostat. Just need some clarification


You need to isolate the transformer circuit. You have two wires from the 110v supply, and two that are 24 volts. When you find those two wires, put one on r and the other on c.
Take a pic of the furnace wiring and let's see what you have
Master of Cold is offline   Reply With Quote
Old 11-03-2011, 08:30 AM   #14
Newbie
 
Join Date: Oct 2011
Posts: 18
Rewards Points: 10
Default

Hooking up new thermostat. Just need some clarification


Here's what I have. According to the schematic 24V from the transformer (top left) is red and yellow which then connect to the circuit board


Last edited by cruzmisl; 11-03-2011 at 05:34 PM.
cruzmisl is offline   Reply With Quote
Old 11-03-2011, 08:20 PM   #15
Member
 
Join Date: Aug 2011
Posts: 729
Rewards Points: 500
Default

Hooking up new thermostat. Just need some clarification


According to the picture, you don't have a common hooked up for the tstat controller. What would help is to place the wires on the commonly used terminals/colors for easy diagnosis and repairs.

Take the wires from the 5 strand harness off of the screw terminals on the furnace board. Place the blue on common, red on r, white on w, green on g, yellow on y.

Now on the controller for the stat, white goes to w1 yellow goes on y, green to g. The red wire is going to go to the r terminals with all the jumpers. The blue wire goes to c. The 2 wire harness can stay where it is.

Advertisement

Master of Cold is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Thermostat issues on old furnace - questions before I replace thermostat. Calab HVAC 11 02-18-2012 09:43 AM
weathertron Mecury Thermostat VickiL HVAC 4 02-06-2011 05:32 PM
Thermostat issues rathipon HVAC 4 01-29-2011 12:46 PM
Need help on hooking up a duct fan to thermostat blackhawk16 HVAC 13 01-01-2010 02:48 PM
Hooking up a non-equipped pellet stove to a home thermostat bobbyc HVAC 4 09-25-2009 03:24 PM




Top of Page | View New Posts