Hi all, like many others I have installed the NOMA Heating/Cooling programmable thermostat Model: 52-2570-6. It is replacing the old round-style analog mercury thermostat dial. The wiring connections on the old one were:

Wire colour:
RED -----------> R
GREEN --------> G
WHITE --------> W
YELLOW ------> Y
BLUE ----------> A

When I connected to the new thermostat, I had the following options for connection terminals: Y, RC, RH, W (has O/B beside it), G, C, and H2 and H1 for the humidifier.

So I hooked up:
RED ----------> RH
GREEN -------> G
WHITE -------> W
YELLOW -----> Y
BLUE ---------> RC

So, it's a forced air, oil furnace. I also have central air, and the humidifier is connected to H1 and H2. Here's what's happening right now.

If I put the fan on the thermostat in Auto mode, the furnace does not kick in when the temperature falls below the set point. However, if I change the fan from Auto to On, the furnace comes on and we're all nice and toasty, but I have to go back and turn it off by switching the fan back to Auto mode. I haven't tried the A/C yet as I wanted to be sure I had things right before messing around some more. There are also Black, Orange and Pink wires that are not being used. To go into some confusing detail check this out.

- Blue and white come in to the house from outside. The blue connects directly to Yellow on the thermostat. The White connects to terminal C on the Furnace itself.
- Red from thermostat connects to red terminal on furnace, and Green from thermostat connects to G on Furnace. Terminals W and Y are not used on the furnace. Blue and White from the thermostat connect to two other terminals on the motor attached to the furnace (blower maybe? I don't know), which are simply labelled T for both. There are two other terminals on the motor labelled F, each has a wire that feeds into the motor. Some kind of relay I suspect.

I don't know if someone can makes heads or tails of this, but if anyone has any recommendations, I would certainly welcome them.

Regards,

sucosam

I may have found my answer. I changed the Heat Cycle Rate from 'Gas or oil forced air (default)' to 'Electric heat'. I also changed the HE/HG setting to HE from the default of HG. I should say that I was positive my furnace was a forced air oil furnace, but didn't really know. I'm going to play with those two settings, but at least now I get the fan to turn on while in Auto mode.

I had this answer composed before I saw your second post.

Usually there is a 24 volt AC transformer in the furnace with the secondary winding connected to a red wire running to the thermostat and a blue wire, common, to the gas valve, A/C relay, and fan relay. From the thermostat there will be white wire to the gas valve, yellow to the A/C, and green to the fan. The thermostat is wired to switch the power from the red to the white, yellow, and green as needed with the blue completing the circuit. Most thermostats and furnaces have the contacts labeled R, B or C, W, Y, and G for the corresponding wire colors. Many have RH and RC to allow separate transformers for heating and cooling. With just one red wire, jumper them. It may be wired to have the A/C control wires return to the furnace and its controls and then a second wire goes to the A/C unit. Internal wiring may replace the green wire if the thermostat does not give you the option of fan only or continuous fan. Digital or programmable thermostats may need the blue wire connected to them.

''- Blue and white come in to the house from outside. The blue connects directly to Yellow on the thermostat. The White connects to terminal C on the Furnace itself. ''

That is correct as long as the hot side of the same transformer is connected to the RC terminal of the thermostat and the C.

''Terminals W and Y are not used on the furnace. Blue and White from the thermostat connect to two other terminals on the motor attached to the furnace (blower maybe? I don't know), which are simply labeled T for both.''

Y is not used at the furnace. It often is used to connect a yellow wire from the thermostat to a wire to the coil outside.

The W from the thermostat needs to be connected to the controls that begin the ignition sequence, the ignitor and pump relay, usually by connecting to the W at the furnace. I am a little confused on the white wires. If it worked with the red connected to R, and the white to W with the old thermostat, it should work with the red connected to RH and the same white wire connected to W. If you had 2 white wires and crossed them, that could be the problem.

Very good information labman, I appreciate your thoughts and time.

So I had the same problem when the setting were:

Fan Auto / Heat
- furnace would start and fan would not

Fan On / Heat
- Fan would be on 24/7 and furnace would turn on when needed


These were my old setting:


H2
H1
B
O
RC - RED
RH - BLUE
G - GREEN
Y - YELLOW
W - WHITE

And here are my new settings:

H2
H1
B
O
RC - BLUE - A
RH - RED - R
G - GREEN - G
Y - YELLOW - Y
W - WHITE - W

** Although I do not think this made a difference as RC & RH are connected threw a jumper **

Also when I tested I had the same problems...

So my solution was the one of sucosam (change the setting from HG to HE) even though I do have a gas furnace.

If your French:

HG – Utilisez ce réglage si vous avez une chaudière à gaz ou à mazout. Ce réglage permet de mettre le ventilateur sous le contrôle du système de chauffage plutôt que du
Thermostat. C’est le réglage correct pour la plupart des systèmes.

HE – Utilisez ce réglage si vous avez un chauffage électrique. Avec ce réglage, le thermostat met en marche en même temps le ventilateur et le système de chauffage.

La barrette est en position 'HG' au départ d'usine. Vous n'avez pas à changer sa position si ce réglage est correct.

Pour change la position de la barrette, tirez sur le petit bloc rectangulaire noir, alignez-le dans la nouvelle position et enfoncez-le bien.

English translation:

HG – Use this setting for gas or oil-fired furnaces.
This setting allows the fan operation to be controlled
By the heating system; not the thermostat. This is the
Correct setting for most systems.

HE – Use this setting for electric heating systems. With this setting, the thermostat will turn on the fan
Immediately with the heating system.

The jumper is pre-installed in the 'HG' position as a factory default. So there is no need to change the jumper if this is the correct setting.

To change the jumper setting, pull out the small black rectangular block and align it to the new position and push it in fully.

English guide: http://www.upm-marketing.com/images/..._Downloads.pdf

French guide:
http://www.upm-marketing.com/images/..._Downloads.pdf


My Summary:

Wires:

H2
H1
B
O
RC - BLUE
RH - RED
G - GREEN
Y - YELLOW
W - WHITE

MODE: HE

Hope this helps a bit...