Have HVAC Questions? Ask an HVAC Expert for Answers
Are there any letter designations on the existing stat's terminals ?
The numbers and rows don't tell us enough.
On the Chromotherm III no there are no or designations
On the TH8000 there are:
On the left (facing the wall plate) Interior and exterior terminals
On the right (facing the wall plate) left interior top to bottom (I believe this is for conventional)
On the exterior of the terminal block (I believe this is for Heat Pump which I have)
Over the top of the left and Right terminal block are Arrows indicating the exterior is "Heat Pump" (which I have) and arrows to the interior of the terminal block indicating "Conventional."
I'm going to hand it off to another expert as I am short on time.
Not at all,
You haven't actually paid until you hit the accept button. Once you are satisfied with the answer.
Okay - Should I wait until the next expert come on?
Go ahead and post the terminal designations, he will need them.
Hi, I think that I can help you. can you please tell me the wire colors you were using originally?
Typically you will use the following.
R - Red wire - 24v power
C - - 24v common/ground
Y- Yellow wire - First stage cooling
W - White wire - First stage heating
G - Green wire - Indoor fan
O/B - - Solenoid valve
I found the following on the Honeywell website, page 3. The link for the manual is http://customer.honeywell.com/TechLit/pdf/PackedLit/69-1896ES.pdf
Heat Pump Terminal Letters:
R Heating power. Connect to secondary side of heating system transformer.
Rc Cooling power. Connect to secondary side of cooling system transformer.
C Common wire from secondary side of cooling system transformer.
Y 1st stage compressor contactor.
Y2 2nd stage compressor contactor.
Aux Auxiliary heat relay.
G Fan relay.
E Emergency heat relay.
L Heat pump reset (powered continuously when System is set to Em Heat; system monitor when set to Heat, Cool or Off).
O/B Changeover valve for heat pumps.
S1 Optional outdoor or remote sensor.
S2 Optional outdoor or remote sensor.
Okay - I took another look at the Chronotherm III and here is what I found
R Terminal - Red wire
B Terminal - Blue wire
Y Terminal - Yellow wire
E Terminal - Black wire (Black is jumper between E Terminal and W2)
W2 Terminal - White Wire & Black Wire (Black is jumper between E Terminal and W2)
G Terminal - Green wire.
On the TH8000 there is a jumber between RC and R - the manual says "Remove factory installed jumper ONLY for two-transformer systems."
How do you know if you have a two-transformer system?
W2 Terminal - White Wire & Black Wire (Black is jumper between E Terminal and W2)there is another terminal O terminal - Orange wire.
You know I cannot say I have ran across very many units that have a two transformer system. There are a few ways you can tell if you have more than one transformer. One is to visibly look behind the panels. Another is to look at your wiring diagram. From your first post it doesn't look like you have a two transformer system. R
I believe I am getting this
R terminal = Red wire
Y terminal = Yellow wire
G terminal = Green wire
O/B terminal = Orange wire
But what about the C terminal on the Chromotherm III with blue wire to what does that connect on the TH8000?
I forgot to ask about the white wire. On the TH8000 there is a terminal W but it appears to be the same terminal as O/B.
I have a white wire and an orange wire on my old thermostat (chronothem III)
Connect W from the old stat to the AUX on new stat.
I am afraid I don't see an AUX - unless it it the S1 or S2 for interior or exterior temp
Do you have an E? These are usully on the left hand side.
What is the exact model of stat you have?
If you look on the back of the stat it will have the model number on it. I need the full model number.
I think what has happened is that you have a stat that is only one heat and one cool. If that is the case , do you know if you have an electric heat bank on your furnace ?
Did they ask you if you had more than one satge of heat where you bought the stat ?
old one The Chronotherm III -- T8611G1103 a horizontal 1 new line 9302
new one The TH8000 series - TH8110U002
electric heat bank on your furnace? How would I know?
Did they ask you if you had more than one satge of heat where you bought the stat? I bought it on line - it said it would work, and since I was replacing a honeywell with a honeywell I thought it would be alright.
That's what I was afraid of. That is a one stage heat and one stage cool stat. That means there is no means of turning on your auxillary heating. If you know for sure that you have electric heat banks in your air handler you won't be able to use this thermostat. If you don't then you don't need the white wire.
To stick with the Honeywell you need a two stage heat and one cool stat, this model number will do it.
TH8320 or TH8321,
There are others also but these are in the same series as the one you have.
Unfortunately they didn't ask you enough questions about your system when ordering the stat.
More than likely you do have at least one bank of electric heat. The easiest way to check is to open the front panel of the unit and look for some thicker wires that will be connected to some heating element terminals.
I know that when the AC is running in the summer the unit (it is a TRANE) outside the house runs as well as the air handler in the house. The same is true when in the winter the unit outside runs and the air handler on the inside runs. What would that mean?
You may not know when the electric heat bank is coming on but basically the first time of the year that it fires up you will get a burning dust smell , do you ever get that ?
The there is a possibility that you don't have auxillary heat. What climate are you in ?
Well you could make a plan that you will just cap off the white wire and let it go until the next time you have a service done on your system and then ask the tech how many banks of heat you have. I still think you are going to have one stage of it but it may have only been used for an emergency heat back up and dedicated as just an auxillary.
On the old Stat
On the new one there is not E or W2 - however on the back of the stat control unit the circurit board does have printed on the board an E and a W2 - Aux. But there is no pin that would fit into the wall mount.
I will wait until I have the unit checked.
Yes , they use the same base board for all the thermostats in that series. The amount of stages needed only causes them to change the front of it. I guess it's more profitable for them that way.
And on the flip side of that , most heat pumps get the aux and emergency wires ran from the stat to their air handler whether they actually have them or not. So you may still not have them. We'll have to wait until we get a set of eyes on them.