Ask Experts Questions for FREE Help !
Ask
    Heron's Avatar
    Heron Posts: 3, Reputation: 1
    New Member
     
    #1

    May 22, 2006, 06:12 PM
    Noma Programmable thermostat
    I have tried to replace a conventional lever action mercury thermostat with a new digital programmable Noma thermostat. The AC works fine but when I turn on the heat, the AC come on then too and not the heat. I have no heat.

    This was the wiring for the original thermostat:
    Orange -> Y
    Red -> RC->RH (same wire loops around one then the other)
    White -> W
    Green -> G
    Black -> not connected to anything

    Following the directions, this is the way I have the new thermostat connected:

    Orange -> Y
    Red -> RC -> RH (instructions said to remove jumper and connect as above)
    White -> W-O/B
    Green -> G
    Black -> still to nowhere

    As I said, I have AC on whether heat or AC is selected and no heat at all. Please let me know what I can do to fix this.

    Thanks
    letmetellu's Avatar
    letmetellu Posts: 3,151, Reputation: 317
    Ultra Member
     
    #2

    May 22, 2006, 07:00 PM
    My first suggestion would be to disconnect the wires from the thermostat and then touch the Red wire to the White wire and see if you get heat. Then I would touch the red wire to the Orange wire to see if the ourdoor unit starts.
    Then do the same with the red wire and the green to see if the air handler starts. If all work that should prove that the wires are all intact and not broken somewhere. If everything works then connect all the wires back to the thermostat but do not connect the RH and RC together. Now test things and see if you have heat. You probably will not have air conditioning. If you have heat and don't have air cond. Then connect the Jumper to the RC and test every thing again. If this does not solve anything post again with the results of your test.
    Heron's Avatar
    Heron Posts: 3, Reputation: 1
    New Member
     
    #3

    May 23, 2006, 03:18 PM
    Quote Originally Posted by letmetellu
    My first suggestion would be to disconnect the wires from the thermostat and then touch the Red wire to the White wire and see if you get heat. Then I would touch the red wire to the Orange wire to see if the ourdoor unit starts.
    Then do the same with the red wire and the green to see if the air handler starts. If all work that should prove that the wires are all intact and not broken somewhere. If everything works then connect all the wires back to the thermostat but do not connect the RH and RC together. Now test things and see if you have heat. You probably will not have air conditioning. If you have heat and don't have air cond. then connect the Jumper to the RC and test every thing again. If this does not solve anything post again with the results of your test.
    letmetellu;

    Thanks a buch for your quick reply. I did everything you said and here's what happened:

    Red-to-white wire= heat turned on
    Red-to-orange wire= outdoor AC turned on
    Red-to-green wire= fan turned on

    All good there.

    Red wire - to - RH (no jumper to RC) nothing happened. The thermostat indicated that heat and fan was on, neither was on.

    Red wire - to - RH->jumper->RC - AC turned on when thermostat was on "cool" and also when thermostat was on "heat"
    letmetellu's Avatar
    letmetellu Posts: 3,151, Reputation: 317
    Ultra Member
     
    #4

    May 23, 2006, 09:12 PM
    My thought is that there is a problem in the thermostat. It is hard to tell you what to do with out being there with an Ohm meter to check things out. You might contack another guy on here is seems to be very good on low voltage, His name is "tkrussel' he might have an idea.
    Heron's Avatar
    Heron Posts: 3, Reputation: 1
    New Member
     
    #5

    May 28, 2006, 09:03 PM
    I replaced the thermastat and everything works fine. Thanks again for your help
    Michou's Avatar
    Michou Posts: 3, Reputation: 1
    New Member
     
    #6

    May 29, 2006, 12:38 PM
    I am having the same problem only, the heat and fan work but the A/C doesn't. I have tried the same steps but I found that when I touched the wires, nothing came on even though they work if they are connected to the thermostat. So at this point, I am just fiddling around trying to get the right combination.
    tstat's Avatar
    tstat Posts: 2, Reputation: 1
    New Member
     
    #7

    Jul 1, 2007, 06:39 PM
    problem:connected t-stat Honeywell (rht7000)installed t-stat set unit to cool instead received heat ,need help fast...
    THANKS IN ADVANCE



    color code of wires:
    rd
    wht/blk
    grn
    y
    bl
    brn
    what
    ///////////////////////////////////////////////
    original connection to non-programable t-stat
    rc & r w/jumper =rd
    wht/blk = o
    grn=grn
    y=y
    bl=x2
    brn=brn
    wht=wht
    jyjtang's Avatar
    jyjtang Posts: 3, Reputation: 1
    New Member
     
    #8

    Jul 20, 2008, 04:14 PM
    Quote Originally Posted by tstat
    problem:connected t-stat Honeywell (rht7000)installed t-stat set unit to cool instead recieved heat ,need help fast...............
    THANKS IN ADVANCE



    color code of wires:
    rd
    wht/blk
    grn
    y
    bl
    brn
    wht
    ///////////////////////////////////////////////
    original connection to non-programable t-stat
    rc & r w/jumper =rd
    wht/blk = o
    grn=grn
    y=y
    bl=x2
    brn=brn
    wht=wht

    I am having the same issue with a Noma programmable thermostat. Set to cool and the unit returns heat. Model 52-2549-0 (touchscreen)
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #9

    Jul 20, 2008, 04:40 PM
    You have the heat and cool wires reversed OR if it is a heat pump you did not make the correct selection on the main programing. Check and read your manual that came with the thermostat.
    jyjtang's Avatar
    jyjtang Posts: 3, Reputation: 1
    New Member
     
    #10

    Jul 20, 2008, 04:58 PM
    Quote Originally Posted by hvac1000
    You have the heat and cool wires reversed OR if it is a heat pump you did not make the correct selection on the main programing. Check and read your manual that came with the thermostat.
    This is a brand new house. Followed the same wiring as the old thermostat (T/S). Put back the old T/S and luckily it still works. No to sound stupid... but I think it may.. how would I know If I have a heat pump or not? The only thing that I am not to sure of is the RC and RH configuration. In the old T/S, there was an additional red wire from RH to RC. I used the same wire in the new T/S even though I think there was the jumper already. Is it necessary for me to add the wire or do I just use the jumper provided? Thanks.
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #11

    Jul 20, 2008, 05:22 PM
    The jumper from RHRC done at the factory should be all you will need. No extra jumper is necessary.
    jyjtang's Avatar
    jyjtang Posts: 3, Reputation: 1
    New Member
     
    #12

    Jul 21, 2008, 02:17 PM
    Just an update, called Noma tech support and apparently the factory default for System Type for this unit was set to 2 - Alternative (O/B wire active when HEATING). Changed to 0 - Conventional and it seems to work. Thanks to HVAC1000 for your suggestions.
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #13

    Jul 21, 2008, 03:31 PM
    Glad you got it going
    coolow's Avatar
    coolow Posts: 1, Reputation: 1
    New Member
     
    #14

    Dec 13, 2009, 06:39 AM
    Somebody help me set my noma thermostat! Lost the manual in a house flood!
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #15

    Dec 13, 2009, 08:40 AM
    Exact model number

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Honeywell Programmable Thermostat [ 2 Answers ]

Should My Thermostats Panel Operate On The 2 Aa Backup Batteries Or Be Hardwired To Common And Have Batteries As Backup When Power Is Out? Panel Lights Up With Batteries In, Does Not Without Batteries. Don't Know Where Common Wire Originates From. Can I Splice Into One Of The Other Wires, G, Y,...

Installing noma digital thermostat [ 4 Answers ]

Hi - I am having difficulty replacing my old thermostat with a Noma brand programmable thermostat. The old thermostat - an old manual mercury type - is connected to 5 wires labelled on the circuit board as G, R, Y, W, and 4. it looks very much like the model shown on this website: ...

Noma thermostat [ 2 Answers ]

Hi, I have a NOMA Programmable 7-Day Thermostat, but today it seems to have gone strange. I had it on the Cool and heat started coming out of the vents. I thought the air conditioning was broken, so I turned the thermostat off, but a little while later the vent came on with hot air again? How...

Noma Thermostat [ 1 Answers ]

I have installed two Noma non-programmable thermostats in my bedroom. On controls the heat and the other controls the AC. My question is, why are the displayed temperatures different on each thermostat? They are literally 2 inches apart and the indicated temp on one is 1.2 degrees higher than on...


View more questions Search