Couple of questions about installing a new digital thermostat
#1
Couple of questions about installing a new digital thermostat
Ok i've got a bit of an older house w/ baseboard heating (water) and my "old" thermostat just blew (wouldn't properly spark to turn on/shut off so it was always on and heating the heck out of the house and costing me a fortune in the process).
Currently i have side-by-side thermostats for heat and a/c but was wondering if (since i have to replace the heat one anyways) i can get a fancy new digital one to replace both (both current thermostats are those old "spin" style... the heat one (which i've just taken off the wall since it's broken) only has 2 white wires to it).
essentially i have 2 questions then: 1) can i get a digital thermostat to replace BOTH the heat (broken) and a/c thermostats i have sitting next to each other, and 2) how can i be sure i install the new heat one properly knowing i only have 2 white wires from the wall?
THANKS!!!
ps it's freezing in here so please help
Currently i have side-by-side thermostats for heat and a/c but was wondering if (since i have to replace the heat one anyways) i can get a fancy new digital one to replace both (both current thermostats are those old "spin" style... the heat one (which i've just taken off the wall since it's broken) only has 2 white wires to it).
essentially i have 2 questions then: 1) can i get a digital thermostat to replace BOTH the heat (broken) and a/c thermostats i have sitting next to each other, and 2) how can i be sure i install the new heat one properly knowing i only have 2 white wires from the wall?
THANKS!!!
ps it's freezing in here so please help
#3
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Thermostat
Since your question pertains to a hot water heating system, you are in the right forum.
Most digitals will work for both heating & cooling. You need to connect one of the heating wires to Rh & the other to W on the new thermostat. It makes no difference which wire goes to which terminal. If your boiler has zone valves with 3 wires to each one, you have heat motor type zone valves. Some digitals are not compatable with this type of zone valve.
Most digitals will work for both heating & cooling. You need to connect one of the heating wires to Rh & the other to W on the new thermostat. It makes no difference which wire goes to which terminal. If your boiler has zone valves with 3 wires to each one, you have heat motor type zone valves. Some digitals are not compatable with this type of zone valve.
#4
hmmm - i checked my zone valves (there are 2) and they have 3 wires coming into them (even though one of the wires is kind of 2 really thin red ones making it look sort of like 4 are going in).
so how do i make sure i get a digital compatible w/ my setup? is there anything to know about my A/C to determine if i can use ONE digital thermostat instead of the two i currently have?
so how do i make sure i get a digital compatible w/ my setup? is there anything to know about my A/C to determine if i can use ONE digital thermostat instead of the two i currently have?
#5
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Digital Thermostat
Nearly all A/C systems use three wires (Rc, Y, & G). You will have to look at the installation instructions which come with the thermostat to see if it is compatable with heat motor type zone valves. Honeywell makes a thermostat (T8775) which I know is compatable. You will need to install the resistor which comes with the thermostat. Before you buy a thermostat look for a name on the zone vavles. If they say Taco (pronounced Tay-co) you will definately need the resistor. They look like this but not all are the gold color. http://taco-hvac.com/en/products.htm...t_category=112
#6
the zone valves i have are honeywell sparco powertrack motorized zone valve operators
kind of like these but not exactly:
http://www.plumbingsupply.com/zonevalves.html
that thermostat you pulled up for me is on the money except for one thing - i'd like to get one that will operate a daily schedule (conservation).
thanks a ton for your help...
ps i may have discovered another problem though - i've pulled the thermostat off the wall but the heat in my upstairs "zone" (controlled by one of the zone valves) is ALWAYS running. I thought it was the thermostat but since it's STILL running w/o the thermostat even hooked up - i guess it's not that? (regardless i'm still changing my thermostat to a combo so no wasted effort here).
kind of like these but not exactly:
http://www.plumbingsupply.com/zonevalves.html
that thermostat you pulled up for me is on the money except for one thing - i'd like to get one that will operate a daily schedule (conservation).
thanks a ton for your help...
ps i may have discovered another problem though - i've pulled the thermostat off the wall but the heat in my upstairs "zone" (controlled by one of the zone valves) is ALWAYS running. I thought it was the thermostat but since it's STILL running w/o the thermostat even hooked up - i guess it's not that? (regardless i'm still changing my thermostat to a combo so no wasted effort here).
#7
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Thanks for the link
That zone valve is not a heat motor type so you should not have to worry about compatability. Another caution about thermostats: Make sure you do not get one which requires a "common" wire. Most battery powered thermostats do not.
Upstairs zone: Label & disconnect the wires to the zone valve & give the pipes 1/2 hr. or so to cool. If they do not cool, the zone vavle is stuck. If they do, there is a wiring problem somewhere. According to the site to which you linked, the operator can be replaced without opening the system.
Upstairs zone: Label & disconnect the wires to the zone valve & give the pipes 1/2 hr. or so to cool. If they do not cool, the zone vavle is stuck. If they do, there is a wiring problem somewhere. According to the site to which you linked, the operator can be replaced without opening the system.
#8
ok i'll try that to diagnose the problem w/ the operator. could be the operator for the upstairs zone is stuck/bad/mis-wired.
thinking ahead to the new thermostat though - i have 2 white wires coming out of the wall for the heat, and i'm supposing 3 for the A/C, so that means i'll be hooking up 5 into the new thermostat right? and all we've come up w/ for me to be sure and look for when buying one is to make sure and get one w/o a "common" wire (so potentially battery operated)?
thinking ahead to the new thermostat though - i have 2 white wires coming out of the wall for the heat, and i'm supposing 3 for the A/C, so that means i'll be hooking up 5 into the new thermostat right? and all we've come up w/ for me to be sure and look for when buying one is to make sure and get one w/o a "common" wire (so potentially battery operated)?
#9
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New Stat
When connecting the wires, make sure the power is off to the boiler & the A/C. Electronics don't like sparks, no matter how small. Most stats come with a jumper between Rh & Rc be sure to remove it. Connect R from the A/C to Rc, Y to Y, & G to G. For heat, connect one wire to Rh & the other to W. It makes no difference which is which.
The vast majority of thermostats which are battery powered do not require a "common" wire.
The vast majority of thermostats which are battery powered do not require a "common" wire.
#10
Grady -
I picked up a Hunter brand thermostat (model 44550, battery powered) which hopefully will do the trick.
Got it home and realized that i have 6 wires coming from the wall (2 whites that went to the old heat thermostat, and 4 (red, orange, yellow, green) that went to the A/C thermostat. The new digital Hunter thermostat appears to only take 4 wires "in".
I assume this means i need to do some twisting of wires from the wall together (prob the power and ground or whatever?). any help?
as always - THANKS.
I picked up a Hunter brand thermostat (model 44550, battery powered) which hopefully will do the trick.
Got it home and realized that i have 6 wires coming from the wall (2 whites that went to the old heat thermostat, and 4 (red, orange, yellow, green) that went to the A/C thermostat. The new digital Hunter thermostat appears to only take 4 wires "in".
I assume this means i need to do some twisting of wires from the wall together (prob the power and ground or whatever?). any help?
as always - THANKS.
#11
Originally Posted by Grady
When connecting the wires, make sure the power is off to the boiler & the A/C. Electronics don't like sparks, no matter how small. Most stats come with a jumper between Rh & Rc be sure to remove it. Connect R from the A/C to Rc, Y to Y, & G to G. For heat, connect one wire to Rh & the other to W. It makes no difference which is which.
The vast majority of thermostats which are battery powered do not require a "common" wire.
The vast majority of thermostats which are battery powered do not require a "common" wire.
#12
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"O" wire?
Normally the only time one would see a wire connected to an "O" terminal is for a heat pump.
Please list the wire colors & to what terminal they were connected on the old thermostat. You may have a heat pump just being used as A/C only.
If you can provide such, a make & model of the outdoor A/C unit may also be helpful.
Please list the wire colors & to what terminal they were connected on the old thermostat. You may have a heat pump just being used as A/C only.
If you can provide such, a make & model of the outdoor A/C unit may also be helpful.
#13
sure (and continued thanks for your help).
the heat thermostat (as you know) only had 2 white wires attached.
the A/C thermostat had 4 coming from the wall, Orange (connected to "O"), Red (connected to "R"), Green to "G", and Yellow to "Y". I used the little tap markers provided w/ the new digital thermostat (and your instructions) to tape them as follows:
R -> Rc
Y -> Y/Y1
G -> G
O -> O/B
I haven't hooked anything up yet, just marked the wires and removed the old thermostats.
I'll have a look outside tomorrow and let you know the make/model of my outdoor A/C unit.
the heat thermostat (as you know) only had 2 white wires attached.
the A/C thermostat had 4 coming from the wall, Orange (connected to "O"), Red (connected to "R"), Green to "G", and Yellow to "Y". I used the little tap markers provided w/ the new digital thermostat (and your instructions) to tape them as follows:
R -> Rc
Y -> Y/Y1
G -> G
O -> O/B
I haven't hooked anything up yet, just marked the wires and removed the old thermostats.
I'll have a look outside tomorrow and let you know the make/model of my outdoor A/C unit.
#14
looks like i have a TRANE XR12 (http://www.trane.com/residential/pro...ners/XR12.aspx) which is a combo heat pump and a/c? might explaing the "O" wire. can i just leave the "O" wire diconnected?
THANKS! (we're almost there).
THANKS! (we're almost there).
#15
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Complete model number
After a little research, I find the XR12 could be either a heat pump or plain A/C. If you can provide a complete model number from the data plate on the unit, I will be able to find out which it is for sure.
Another help would be if you can find out where that "O" wire goes. Sorry to be such a bother but I don't want you frying something.
Another help would be if you can find out where that "O" wire goes. Sorry to be such a bother but I don't want you frying something.
#16
grady the absolute LAST thing you're being is a bother - you're really helping me out here so keep the questions coming so you can help me get this right...
the XR12 model number (it's a long one) from the data plate is:
2TTR2036A1000AA
you second question was where the "O" wire goes... i'm not 100% sure what you're asking here but the orange wire came out of the wall and went to the "O" marked screw on the OLD thermostat (even though the old thermostat had nothing to do w/ heat, only A/C).
On the NEW thermostat, there is a "O/B" screw that i assume it will go to (but i haven't hooked anything up yet - waiting on you).
THANKS!!
the XR12 model number (it's a long one) from the data plate is:
2TTR2036A1000AA
you second question was where the "O" wire goes... i'm not 100% sure what you're asking here but the orange wire came out of the wall and went to the "O" marked screw on the OLD thermostat (even though the old thermostat had nothing to do w/ heat, only A/C).
On the NEW thermostat, there is a "O/B" screw that i assume it will go to (but i haven't hooked anything up yet - waiting on you).
THANKS!!
#18
ok on further investigation those wires (from the thermostat) go to an air handler in my attic (also a trane, model TWE036C14080). looks like it's a combo A/C slash heat pump that's being only used for A/C.
I took the access panel door off and it's pretty much impossible to tell where the orange ("O") wire goes (there's a series of twisted together wires going through various checkpoints etc.).
I took the access panel door off and it's pretty much impossible to tell where the orange ("O") wire goes (there's a series of twisted together wires going through various checkpoints etc.).
Last edited by zilla31; 12-23-05 at 11:48 AM.
#20
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Orange Wire
I THINK hooking the orange wire to the O terminal on the new stat would work ok but I'm not positive. What make & model T-stat did you get. I would like, just for my own curiousity, to see if I can find out anything on the manufacturer's web site.
#21
it's the hunter brand "auto saver 550". i'll prob try and hook it up tomorrow... even though i think i have a bigger problem ultimately (the heat has still been running upstairs whenever the boiler is on even WITHOUT ANY THERMOSTAT HOOKED UP!
I think maybe one of the zone valves (i have 2 - 1 upstairs, 1 down) is screwed up and in an always "on" position. Basically i'm having to control the heat in here by shutting on/off the boiler.
W/ your help though i can at least get past installing the new thermostat - then i can start asking you guys about the greater problem once we've got that handled
I think maybe one of the zone valves (i have 2 - 1 upstairs, 1 down) is screwed up and in an always "on" position. Basically i'm having to control the heat in here by shutting on/off the boiler.
W/ your help though i can at least get past installing the new thermostat - then i can start asking you guys about the greater problem once we've got that handled
#22
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Hunter
From what I can tell, it looks like you could connect the O wire to the O terminal. Start with the "normal, O, B switch in the normal position. You may end up having to move it to the O position. It might be worth a call to Hunter for better info. Personally, I don't see why you could not connect the orange wire & the Y wire to the Y terminal. This should energize the reversing valve when ever there was a call for cooling.
#23
ok i hooked it all up and programmed it. first thing i noticed is that if i set the fan selector to "on" the fan WILL come on (A/C), but if it's on "auto" it won't come on even though the temp in here is 78 and the desired temp is set to 65.
** PS i found in the instruction manual the info for the "O" wire (help me decipher):
by the first paragraph it seems i should leave it in the NORMAL position, but by the time i finish reading the second paragraph, seems like i should set it to "O"? Right now it's in NORMAL.
** PS i found in the instruction manual the info for the "O" wire (help me decipher):
Furnace or Heat Pump selector (NORMAL - O - B switch):
The factory position for this switch is in the NORMAL position. Leave it in this position if you have ANY system that uses gas, oil, electric, or hot water heating.
If you have a single-stage Heat Pump (no aux or emergency heat source), then slide the switch to the position that matches your Reversing Valve type. If your heat pump system has a "B" wire, slide the switch to "B" for your reversing valve that activiates in HEAT mode. If your heat pump system has an "O" wire, slide the switch to the "O" for your reversing valve that activates in COOL mode.
The factory position for this switch is in the NORMAL position. Leave it in this position if you have ANY system that uses gas, oil, electric, or hot water heating.
If you have a single-stage Heat Pump (no aux or emergency heat source), then slide the switch to the position that matches your Reversing Valve type. If your heat pump system has a "B" wire, slide the switch to "B" for your reversing valve that activiates in HEAT mode. If your heat pump system has an "O" wire, slide the switch to the "O" for your reversing valve that activates in COOL mode.
#24
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Clear as mud
I know what you mean. When I read the instructions, I was not totally clear on them either. That is why I was thinking of connecting both the O & Y wires to the Y terminal. By doing this, the reversing valve would switch to the cooling position whenever there was a call for cooling. I'm going to ask one of our heat pump gurus to look at this thread & see what he thinks.
I don't know how long you tried the fan in auto but many air handlers have a delay in the fan to allow the refrigerant to actually start cooling before they bring the fan on. This delay is generally on the order of 30-45 seconds.
I don't know how long you tried the fan in auto but many air handlers have a delay in the fan to allow the refrigerant to actually start cooling before they bring the fan on. This delay is generally on the order of 30-45 seconds.
#25
yeah it's weird - if i have the stat in COOL mode then the fan WILL come on automatically by temperature, but not in when in AUTO mode. For the meantime i switched the heat to the "O" setting (based on their instructions) but i'll def wait to hear back from you (in case i need to just twist it w/ the Y).
Grady - THANKS for all your help on this and HAPPY HOLIDAYS partner - you're saving me a fortune i'm sure
Grady - THANKS for all your help on this and HAPPY HOLIDAYS partner - you're saving me a fortune i'm sure
#26
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I think Grady is on the right track here. Trane heat pumps use O to energize the reversing valve. I would agree with him that in this case, you should put it with the Y wire. Since you are not using it for heat you wont have a problem. Im not sure of the hunter thermostat as I have never seen one. Im sure it will work fine. Did you turn the power off to the air handler before hooking it up?
#27
Merry Christmas everyone!
Ok, Grady asked for my help! :-)
Ok, The unit you got is NOT a heat pump.
Your model is 2TTR2036A1000AA
2TTR is A/C only, and 2TWR is Heat Pump
air hander is made to do both.
So undo the O wire and forget it even is there.
So
From the A/C
R---red---RC
G---green---Green
Y---yellow---Y
From the boiler.
Rh---red--R
W---white---W
Ok, Grady asked for my help! :-)
Ok, The unit you got is NOT a heat pump.
Your model is 2TTR2036A1000AA
2TTR is A/C only, and 2TWR is Heat Pump
air hander is made to do both.
So undo the O wire and forget it even is there.
So
From the A/C
R---red---RC
G---green---Green
Y---yellow---Y
From the boiler.
Rh---red--R
W---white---W
#29
thanks guys a MERRY CHRISTMAS!!! I just took off the stat cover and noticed that the yellow termnial (new stat now) is all brown and fried looking
everything was hooked up just like Grady (and now Jay11J) said except the "O" wire which i've not disconneced and capped off.
everything was hooked up just like Grady (and now Jay11J) said except the "O" wire which i've not disconneced and capped off.
#32
Oh no..
Well, To be honest, I have not heard many good things about Hunter T-stat. Undo the Hunter and if you need heat does the old a/c stat have heat switch on it?
If yes, then hook up R and W on that stat to get by till you get a new one.
If the new hunter still works (heat). just undo the Rc and Y wire for now.
Well, To be honest, I have not heard many good things about Hunter T-stat. Undo the Hunter and if you need heat does the old a/c stat have heat switch on it?
If yes, then hook up R and W on that stat to get by till you get a new one.
If the new hunter still works (heat). just undo the Rc and Y wire for now.
#33
the OLD stat did not have a heat selection at all... it was just for controlling A/C. I ended up gong w/ Jay11J's advice on the "O" wire and just capped it off (going nowhere). did we finally decide if that should go nowhere OR be connected to the "Y" terminal w/ the "Y" wire too?
i think i'm going to trade this Hunter in for a Honeywell here on tuesday (after all my holiday family business the next 2 days)...
i think i'm going to trade this Hunter in for a Honeywell here on tuesday (after all my holiday family business the next 2 days)...
#34
Member
a few choices
You could use the original Honeywell T87F Round thermostats it sounds like you have and just install a new Honeywell Q539-1147 sub base and use only one of the old round T87F Round thermostats and keep the other as a spare. The new sub base has isolation capability (Rh and Rc), what this does is allow your thermostat to use two power source transformers. One from the boiler, and one from the air handler. The sub base has Rh, Rc, W,Y,G. These are the only connections you need. Rc and W for the two wire to heat, and Rc for the red wire for cooling low voltage power, Y for yellow to pull in the contactor for cooling, and G (green) for the fan in cooling.....Done!
Mount the original thermostat that was on the heat side to the sub base after the wires are connected, and write down the anticipator setting somewhere (likely about .4a) and set the other one for the same and put it away as a back up which you'll likely never use. And the tackle the real problem..... the zone valve.
Oh, I believe you can get that subbase at HD but they are white now, you likely have the gold stat which I dont think are made any longer.
Mount the original thermostat that was on the heat side to the sub base after the wires are connected, and write down the anticipator setting somewhere (likely about .4a) and set the other one for the same and put it away as a back up which you'll likely never use. And the tackle the real problem..... the zone valve.
Oh, I believe you can get that subbase at HD but they are white now, you likely have the gold stat which I dont think are made any longer.
#35
hvac - i think i follow you but my wife is really pushing the idea of a "programmable" thermostat to help us conserve.
plus the "old" stats are totally different; the heat only one had just the cylindrical slider (no switches at all), and yes it was gold the second one, used for A/C only) was also a gold round that looked very much like the heat one except it DID have switches for fan ("on" and "auto") and cool ("cool" and "auto").
I think my next action will be to replace the Hunter (which now has that burned out "Y" terminal) w/ a Honeywell digital programmable and hook up all the wires (as labeled) except "O". What do we all think about that?
plus the "old" stats are totally different; the heat only one had just the cylindrical slider (no switches at all), and yes it was gold the second one, used for A/C only) was also a gold round that looked very much like the heat one except it DID have switches for fan ("on" and "auto") and cool ("cool" and "auto").
I think my next action will be to replace the Hunter (which now has that burned out "Y" terminal) w/ a Honeywell digital programmable and hook up all the wires (as labeled) except "O". What do we all think about that?
#36
Member
programmable
the heat only, is heat only, because the switches are not contained in the thermostat, but rather in the sub base to which the wires are connected, and then the thermostat is connected to the sub base with the three screws of the thermostat. These three screws make the electrical connection to the sub base. Any time you wire a thermostat its best to kill the power to the air handler and the furnace or boiler which ever the case may be. If your determined to go programable, the Honeywell T8602D Chronotherm IV is a nice one that does heat, cooling, and autochangeover, it has a selectable fan switch that can also program the fan during different periods to on or auto, it also does heat pumps, dual or single transformer applications, and you can actually calibrate the temperature sensor to reflect actual room temps if it goes out of calibration. It does alot! You can actually install a sensor outside and have it tell you the outdoor temperature on the face plate and a daylight savings switch .....I have it in my upstairs, although I only use it for heat, it works great. Keep in mind these stats have a 5 minute time delay unless you program it not to ( this is do-able).
#37
ok i'll def look at that thermostat (is this it?):
http://www.store.yahoo.com/air-n-wat...7dayprogc.html
ps - are you familiar enough w/ this stat to tell me what to connect to what based on the thread above (which will tell you which wires i have coming from the wall needing to go somewhere).
pps - you think they have this stat at Lowe's or HD? i'm out of town for a week starting wed so kind of want to get this resolved tomorrow while i'm off work... THANKS!!
http://www.store.yahoo.com/air-n-wat...7dayprogc.html
ps - are you familiar enough w/ this stat to tell me what to connect to what based on the thread above (which will tell you which wires i have coming from the wall needing to go somewhere).
pps - you think they have this stat at Lowe's or HD? i'm out of town for a week starting wed so kind of want to get this resolved tomorrow while i'm off work... THANKS!!
#38
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zilla31
I still want to know where that 'O' wire travels. The model number off of the air handler might help. I know you gave us the model of the outdoor unit but I'm thinking the outdoor unit may have been replaced at some point in time & the old air handler left in place.
#39
Grady, I gave you the link to the manual on the air handler.. Trane's air handler is made for both.
The honywell t-stat can be found at home depot.. They got the Honeywell Vision t-stat. I put one on for a friend about a month or so ago, and they have been happy with it.
When you do hook it up. Make sure power is killed for BOTH equipements. and remove the jumper wire.
The honywell t-stat can be found at home depot.. They got the Honeywell Vision t-stat. I put one on for a friend about a month or so ago, and they have been happy with it.
When you do hook it up. Make sure power is killed for BOTH equipements. and remove the jumper wire.
#40
ok jay - i'll look for the Honeywell Vision today (that's an ok one to get instead of the T8602D Chronotherm IV?). thanks guys (a ton). heading to st. croix for a 10 day vacation w/ wifey tomorrow so i won't need much heat/a/c there thank God! whatever i can't get done today on this i'll address when i get back (so you guys know i didn't disappear totally).
THANKS!!
THANKS!!