White Rodgers to Nest


  #1  
Old 01-07-16, 07:25 PM
C
Member
Thread Starter
Join Date: Jan 2016
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
White Rodgers to Nest

Hello all. I have a White Rodgers LR27935 Thermostat that I want to replace with a Nest 3rd Gen.

Here is my current wiring, I have browsed google and tried to figure out the wiring myself but I am stumped.

I have installed the wiring and its working however when the heat turns on its lukewarm and will run for 30+ min without heating the room. Previously the heat would come on with White Rodgers thermostat and be warmer than it is now. There is a black wire that I have no connected I trimmed and covered up. its inactive in the wall. Can you confirm that this is the correct way? Im trying to figure out if I need the Black Wire on ( E ) post on White Rodgers.

Heat & Air do work. Fan works.

Here are previous wiring in thermostat.


and here is the current wiring into the nest.



Thank you
 
  #2  
Old 01-07-16, 07:37 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
I would land black on the star terminal and set the stat to use it for emergency heat but this does not explain your symptoms.
 
  #3  
Old 01-07-16, 07:40 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,872
Received 1,480 Votes on 1,368 Posts
Welcome to the forums.

Right now.... without the black wire connected.... your system is running on heat pump only. That means the backup electric heat is not active.

You need to wire the stat for heatpump operation with back up electric heat. That would be black needs to be probably on the W2 terminal.

Most stats run the heatpump and when the room temperature is 4 or more degrees below the set point.... the electric heat is turned on. This is the reason why a set back stat is not recommended on a heat pump system. It is much more cost effective to let the heatpump run without using the electric heat.
 

Last edited by PJmax; 01-09-16 at 12:26 AM.
  #4  
Old 01-07-16, 07:42 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
I agree that this would increase comfort but W2 was not in use with the old stat?
 
  #5  
Old 01-07-16, 07:50 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,872
Received 1,480 Votes on 1,368 Posts
So on the old W/R stat.... E is emergency only ?
 
  #6  
Old 01-07-16, 07:56 PM
C
Member
Thread Starter
Join Date: Jan 2016
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
From what I see,


Old Thermostat
Red wire - R
Green wire - G
Orange wire - O
Blue Wire - C
Black Wire - E
Yellow Wire - Y

New Thermostat
Red Wire - Rc
Orange Wire - OB (set to O on settings)
Green Wire - G
Yellow Wire - Y1
Blue Wire - C
Black wire - Not Connected but I just connected it into W2/Aux


I live in a apartment and have Electric Heat pump. Its a Goodman ARUF182416CA.

I might have to peep inside and see how its wired in there
 
  #7  
Old 01-07-16, 08:09 PM
C
Member
Thread Starter
Join Date: Jan 2016
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
Thank you 2 for the quick responses The heat is working better. Its nice that there is 4 feet of wire from the unit to the wall its all right there so if anything I can run a new bundle of wire ( our maint tech here is pretty useless... it took 4 days for him to replace a outlet and it was wired incorrectly 2 times).
 
  #8  
Old 01-07-16, 09:16 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
The old white Rodgers thermostat was a 1F58-58. That lot number on post 1 is not the model number.

The model number is probably on the back of the stat.
The last two digits may differ.

E is a separate circuit on every manual that I bring up but connecting black to Aux will definitely increase comfort.
 
  #9  
Old 01-07-16, 09:30 PM
C
Member
Thread Starter
Join Date: Jan 2016
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
As far as I know, this is where I got the model number and typing it into google.

Thank you. I think its heating just not too well at the moment. Will investiage further when I get off work tomorrow. Thank you again

here are a few images

Front




Inside back cover

 
  #10  
Old 01-07-16, 09:52 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
  #11  
Old 01-08-16, 06:42 AM
A
Member
Join Date: Jun 2012
Location: USA
Posts: 1,679
Received 50 Votes on 45 Posts
Assumption is you used to move the old thermostat to the EMER setting to have warmer air.
 
  #12  
Old 01-08-16, 09:35 AM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
I usually see the heat strip wire land on W2 with a jumper from W2 to the E terminal but Nest does not support this.

It seems like it would be easy for them to update the software and use W2/Aux for stage 2 and emergency heat.

Emergency heat isn't even under the same flag icon as the other modes when the star terminal is used. (But perhaps I am just a biased diehard Honeywell fan)

I would measure the delta tee across the indoor unit with only the heat pump and then with both stages of heat.

The outdoor temperature can also have a great impact on heat pump performance. You might have over 30 degree delta tee if it is in the upper forties but closer to 16 or 17 below freezing. Defrost cycle would also make the delta tee lower.

I work with over 10 times more Geothermal heat pumps than dx models and I rarely see standard heat pumps on days below 50 degrees. Perhaps the performance is a little better these days.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: