[hans-Dieter]

hello I'm glad there is a place to ask question and getting good answers


I installed a rth7400 honeywell thermostat on my york furnace honeywell burner

and I can't get heat out of it

W \ white wire
B \ clear wire
Y \ yellow wire
O \ orange wire
R \ red wire
X \ Brown wire
G \ green wire

I can get some cold air out of my pump but not heat

here my setup

[hans-Dieter]

Sorry I forgot too say ived been able to get heat from furnace but with oil (emergency heat ) and I don't want a pay 600$ just in oil I pay less when it's with system/pump

Thank's

[hans-Dieter]

I can ad this info to

First are the thermostat (red) black are my wires

The way I'm connected


C/ B
G/ G
Y/ Y
O/B/O
R/C
R/ R (jumper with R/C

W2/ W
Y2/ X

[hans-Dieter]

That whas my old one

[hans-Dieter]

More like this one sorry it's been already a long time I forget to take pic before recycling it

[dac122]

Offhand it doesn't look like you've wire up anything wrong, but the only way I can be sure is to diagram your systems behavior with the old tstat and the wiring to air handler and heat pump.

Have you verified that the O/B terminal (which usually (de)energizes the reversing valve) is doing the right thing in heating and cooling mode. Some thermostats and/or HPs are backwards from others.

Is there any way you can wire the old tstat back in? I know that's a pain, but if you can, you can put the system into its different modes (heat, cool, them heat, fan only, heat + aux) and see the behavior on all the terminals. You'll need a volt meter to do that.

Just in case you're not sure here is a semi standardized thermostat wiring color map.

Funny I have one of those old Honeywell non programmable tstat at home in my shop.

I will take a better look at you pics to see if I see anything else wrong, and will post accordingly.

[hans-Dieter]

No I give it to my recycling warehouse (because they whas mercur in it) and when I install it , it whas in summer and it whas warm outside so my pump whas working fine for the cool air... I didt check if it whas working on heat mode :( I use to have a other old thermostat but it don't have all the same number and letter on it ( maybe just for a heating fonction.

[dac122]

What terminals are energized in heating mode versus cooling mode?

[hans-Dieter]

Function 170 set it to 7 190 set it to 0 because if I remember when 190 whas set to 1 I wahs getting cold!.

I'm really not familiar with electricity I have this but I don't know how to use it

Do I need to check it with this thing :) if yes can you help me by telling me wich wire and where (on the fucnace or on the thermostat )

[hans-Dieter]

Should I take a video ? Of my furnace when it work or something else ? I can host that :) like you see I'm not to bad for hosting pics :)

[dac122]

Don't take this personal, but if you aren't comfortable checking voltages you really should get a pro. I could try talking you through this but I'd be afraid you might short out your tstat, a control module or transformer. You at least have heat right now. I don't want to make it any worse.

[hans-Dieter]

OK now I'm getting sum heat with my pump I set my thermostat to heat pump with aux # 7 at the 170 function and to cooling changeover valve # 0 at the 190 function
Is that OK to let go the pump in winter time even at -30 degres Celsius? Or it will automatically go on (aux) oil mode at -12?

Thank you

[dac122]

ok now im getting sum heat with my pump i set my thermostat to heat pump with aux # 7 at the 170 function and to cooling changeover valve # 0 at the 190 function

Looking at the manual I think you have it. 170=7 is multi-stage and 190=0 energizes the reversing valve correctly for your HP as I hinted at earlier. Your tstats default is backwards from your HP.

Does your cooling now work?

Also make sure function 180, 240 and 270 are set correctly. My concern would be the fan would shutdown too soon and leave your heat exchanger too hot, but its unclear to me exactly what those functions do.

BTW write down all these values when you get things correct in case the tstat loses them.

is that ok to let go the pump in winter time even at -30 degres celcius?? or it will automaticly go on (aux) oil mode at -12??

thank you

It is okay to let the HP run down to some low temps even though it will not satisfy all your heating needs. At low temps it will run a little followed by your furnace picking up the slack. But at some point you may need to lock out the HP to prevent possible compressor damage. I don't see anywhere in the manual where you can lockout your aux above a certain temp to maximize your dollars, nor lockout the HP below a certain temp to protect the compressor.

You can leave 300=1 and when outdoor temp gets below say 10 degrees F switch to EM/Aux heat only. Contact the manufacturer and see if your HP has a safety low temp lock out in its control module. If not, ask them what is a safe temp. Remember some of those low temps may be reached when you are asleep.

There is also an economic balance point where based on your electric rates, oil price, efficiency of your furnace and HP COP numbers you may want to switch over to just furnace sooner. If you have those numbers let me know and we can figure that out. I'm betting however, if oil is as expensive there as here you want to run that HP to the lowest temps that are safe.

[hans-Dieter]

OK tomorrow ill try to call honeywell they gave me a phone number in french.. easyer for me

For now I'm getting warm it's set ate 23 degres Celsius and it stay on it . When the pump start the fan start , when the pump stop the fan stop...