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airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8049
Experience:  Furnace, A/C and heat pump specialist.
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I'm replacing a York thermostat(7 wire - mechanical) with

Customer Question

Hello,I'm replacing a York thermostat(7 wire - mechanical) with Honeywell RTH6500-(Conventional system).
where do the blue and orange wires connect to?Per the instructions: I will be connecting the following , please verify.red to Red/RC jumped
green to G
X to C
yellow to Y
white to W
Submitted: 6 months ago.
Category: HVAC
Expert:  BillyHvac replied 6 months ago.

Hello,

My name is ***** ***** I will do my best to assist you. I am looking over your question now and will respond shortly.

Expert:  BillyHvac replied 6 months ago.

Were all 7 wires attached on old thermostat?

Is this a zoned system with more than one thermostat?

Customer: replied 6 months ago.
Actually, there were 8 wires. A brown wire was not connected to the thermostat. Yes, all seven wires were connected to thermostat. No, there is only the one thermostat.
Expert:  BillyHvac replied 6 months ago.

Thank you.

If there were 7 wires attached this would likely be a heat pump or 2 stage heat or cool..

Can you tell me what color wire was on what terminal on old thermostat?

Customer: replied 6 months ago.
orange-O
red-R
green-G
blue-B
yellow-Y
I believe black-X
white-W
If the system is a heat pump, there is an air conditioning unit attached from outside.
Expert:  BillyHvac replied 6 months ago.

Is it is possible that we have electric back up heat that would have been labeled X2?

Customer: replied 6 months ago.
No.
Expert:  BillyHvac replied 6 months ago.

Ok here is the issue.

A conventional system is only R,W,Y,G and occasionally C

A heat pump is R, aux,Y,G, O...but never are O and B used at the same time unless it is a zoned system.

The best way is to go to the other end of the wire in the indoor blower unit and mimic the wiring found there. Can you open the indoor unit?

Customer: replied 6 months ago.
Unfortunately, the home is several miles away; but I am willing to go.
Expert:  BillyHvac replied 6 months ago.

Ok, not to bore you..but the b and o are accessory terminals that mimic Y and W (heat and cool)

Y turns on compressor while O activates reverse valve to make cooling.

So we cant have a B heat accessory hooked up the same time a O is hooked up therfore most thermostats have an O/B terminal and pick which it is to be.

Normally these things are straight forward, but with this system I would need to see the other end of the wire..

Customer: replied 6 months ago.
No bore at all. I will reconnect with you on arrival to home.
Expert:  BillyHvac replied 6 months ago.

any pictures of wiring....old thermostat and connections help.

Just in case I am offline when you return, I am going to open this question so someone else could help..

Billy

Expert:  airheatman replied 6 months ago.

Look likes Billy had to leave but I will be happy to assist you from here.

Expert:  airheatman replied 6 months ago.

Here is how you will want to wire and I will explain what each wire does.

Orange controls the reversing valve so it will go to the O/B terminal

Red is 24v power so it will go to R with a jumper to RC

Green controls indoor blower,it will go to G

Yellow controls outdoor unit contactor so it will go to Y

Black would have been Emergency heat on old thermostat since it went to X

and White would have been Auxilliary heat since it went to W

Therefore since the new thermostat has a combined AUX/E terminal, both black and white will go to the AUX/E

Blue is 24v common so it will go to C

Expert:  airheatman replied 6 months ago.

Now to clear things up, since you had a O wire connected,you do have a heat pump, not a conventional system. If you can give me model on outdoor unit I will send documented verification for you.

So after wiring as listed above we need to go to System setup and match the thermostat o your system.

Let me now if you need help getting to the setup menu and I will guide you.

Select the following for each function to match the thermostat to your system.

1=5

2=0

3=1

5=9

6=9

Any other functions are at your discretion.

If any functions listed do not show available, this means thermostat has setup based on a previous selection.

I will be standing by to help you with any and all questions.PLease give me that model on outdoor unit if you can as son as you arrive.

Thanks for letting me work with you.When we are finished, if my answer has been polite, professional,and thorough, please click one of the ratings . If you still need help let me know!.Expert is not paid for assisting you until you rate answer.Feel free to follow up for 30 days at no additional cost. Bonus always appreciated if you feel justified.

Customer: replied 6 months ago.
Model# ***** *****
Expert:  airheatman replied 6 months ago.

Excellent Thanks for hat information. Below will show that this is indeed a heat pump

Expert:  airheatman replied 6 months ago.

Quick question.Did you try to operate the system after connecting the wires you mentioned and did you turn off power at air handler before starting?

Customer: replied 6 months ago.
No. I had just got in and went outside to acquire model number.How shall I proceed now. Turn of power at air handling unit and connect wires? The unit also has AC.
Expert:  airheatman replied 6 months ago.

Perfect. The reason I ask is there is a bit of confusion about the B and X wires .On some older thermostats, B is COMMON and X is Emergency heat.(This is what you have)

On newer thermostats B is for reversing valves on certain units.

If you were to connect the blue wire to B or the X wire to C, you would immediately burn up a transformer or fuse if you turned it on.

Proceed to wire exactly as I stated in my first post.

Expert:  airheatman replied 6 months ago.

The phone call is optional. If you would rather talk on phone there is an additional fee, but usually makes it easier.Otherwise we can continue here in chat as long as it takes.

Expert:  airheatman replied 6 months ago.

Still with me?

Expert:  airheatman replied 6 months ago.

I am about to have to leave office for the night as it is 11:40 here. If you still have questions, let me know.I will see post in the morning and get back to you.

Customer: replied 6 months ago.
Good afternoon,I have everything hooked up. Iam now at system setup. Per the Manual I should just set the system to zero. However, I noticed you have 5 settings I should input. How should I proceed?
Customer: replied 6 months ago.
Manual indicates if O wire is connected to O/B terminal, which it is my setting should be zero.
Expert:  airheatman replied 6 months ago.

See page 18 in manual below:

https://customer.honeywell.com/resources/techlit/TechLitDocuments/33-00000s/33-00130EF.pdf

First we have to select system Type Function 1 Select 5 for heat

pump with backup heat

Next function 2 tells thermostat what mode to energize reversing valve -Select 0

Function 3 tells thermostat if your fan is operated by an electric air handler or gas furnace - Select 1

Function 5 and 6 are heat cycle rates - Select 9

Customer: replied 6 months ago.
Functions 3&5does not appear on screen. I input values you indicated for 1,2,6.
Customer: replied 6 months ago.
I do have 1 brown wire that is not connected to new thermostat, and was not connected to old thermostat; but is connected to heat pump. Just wandering if brown wire should be connected also?
Expert:  airheatman replied 6 months ago.

Any functions that do not appear as you follow the list I sent are automatically set based on a previous selection,Do not worry about them.

The brown wire is for a Thermistor in outdoor unit. Went to T on some older thermostats.N ot used with todays thermostats.Tape off and shove in wall.

Customer: replied 6 months ago.
OK. I checked AC, works fine; but heat is not working.
Expert:  airheatman replied 6 months ago.

Does outdoor unit come on when you select heat? Also did you wait 5 minutes between modes to allow for time delay in thermostat?

Customer: replied 6 months ago.
Sorry, heat just kicked on. Thanks soo much for your assistance!!!
Expert:  airheatman replied 6 months ago.

If you have further questions, please let me know.

Thanks for letting me work with you.If my answer has been polite, professional,and thorough, please click one of the ratings before you go. If you still need help let me know!.Expert is not paid for assisting you until you rate answer.Feel free to follow up for 30 days at no additional cost. Bonus always appreciated if you feel justified.

To rate answer, please select one of the stars on the page.

Customer: replied 6 months ago.
OK.
Expert:  airheatman replied 6 months ago.

Thanks for letting me help

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