Nest Thermostat - Why?

[wappinghigh]

My wife and I have very different schedules and the C4 thermostat works a treat for us (we have 5).

A smart thermostat really would be difficult for us - we simply NEVER touch the adjustments and are very happy.

Bill

Yeh..I with ya here...just how does a "smart thermostat" know whether it's a women or a man in the room?..in my experience women feel "hot"..or "cold" in a totally different (and random) fashion to men....

[CFUG]

another issue is that there were *major* changes to the tstat functionality in 1.8+. for those of us still on 1.7 the nest is a heck of a cheaper/easier/simpler way to upgrade our hvac control without going through the entire C4 2.x upgrade.

You're assuming it works.

[wingzz]

No you don't. If you have any Control4 touchpanels or the on-screen' date=' you can setup the Thermostat programming via Navigator.

RyanE[/quote']

That's good. I didn't know that. I just assumed the dealer had to add all the logic....

Ryan is this true even in the older versions, like 1.74?

[RyanE]

I probably should correct myself... You can setup Thermostat *scheduling*, not *programming*, like ComposerPro programming.

That said, ComposerPro programming is not necessary for a stat to work properly.

RyanE

[RyanE]

Ryan is this true even in the older versions, like 1.74?

I do not know. It's been a *long* time since I've used anything pre 2.0.

Sorry.

RyanE

[drousso]

Control4's thermostat can operate independently of a Control4 system, and when you make changes to the schedule within the project, they're pushed to the thermostat. It really has to be done this way, since you don't want your HVAC to stop working if your Control4 system is offline for any reason.

Just experienced NIGHTMARE install with C4 TStat. Horrible! And still not working...

I use conventional single stage HVAC. Rh+W1=Heat, Rc+G+Y1=AC, no common. My Honeywell TStats, TH8000 series ran PERFECT. I tried to use C4 TStat and ARGH the nightmare begins.

First, if your system doesn't have Common, you use power stealing. However, usually no big deal since most ALL COTS therms handle power stealing without issue. Not true in C4 case. Their therm uses Rh lead for stealing, perfectly normal, but will OPEN the Rh relay when calling for Rc (AC) when power stealing is enabled. So what happens is the AC AND the HEAT will run at the same time. They tell you to use the U shaped jumper between Rh and Rc on single stage installs, but you can't do that when an install has two transformers already (as in a lead for Rc and Rh already). They tell you to use the 720Ohm resistor between W1 and Common when power stealing, but that is only to dissipate potential voltage overages. There is no logical explanation to open the Rh relay when power stealing, none!

To net it out in summary;

When using Power Stealing, the thermostat will charge the Rh connection even when calling for AC.

This is an engineering flaw on the C4 thermostat and likely the reason so many dealers bitch about C4 TStat installations. This is NOT standard practice for thermostat behavior and any HVAC specialist will tell you this. If the C4 thermostat didn't do this one thing, it would have installed just fine... The bottom line advice I can give is that you must have a COMMON lead on your HVAC system to use the C4 TStat, or run it using BATT only and be prepared to replace the battery several times a year.

Secondly, while C4 TStats can operate independently of a C4 system, you CAN'T program them independently other than to turn them on or off, or set a basic temp hold. The only way to get to the 7 day programming is through the Director UI... and the only way to program startup times, cool off periods, and other run time tuning is to PAY A DEALER. STUPID! I want to un-ring this bell so very badly. I would NEVER recommend a C4 TStat.

[ichbinbose]

Control4's thermostat can operate independently of a Control4 system, and when you make changes to the schedule within the project, they're pushed to the thermostat. It really has to be done this way, since you don't want your HVAC to stop working if your Control4 system is offline for any reason.

Just experienced NIGHTMARE install with C4 TStat. Horrible! And still not working...

I use conventional single stage HVAC. Rh+W1=Heat, Rc+G+Y1=AC, no common. My Honeywell TStats, TH8000 series ran PERFECT. I tried to use C4 TStat and ARGH the nightmare begins.

First, if your system doesn't have Common, you use power stealing. However, usually no big deal since most ALL COTS therms handle power stealing without issue. Not true in C4 case. Their therm uses Rh lead for stealing, perfectly normal, but will OPEN the Rh relay when calling for Rc (AC) when power stealing is enabled. So what happens is the AC AND the HEAT will run at the same time. They tell you to use the U shaped jumper between Rh and Rc on single stage installs, but you can't do that when an install has two transformers already (as in a lead for Rc and Rh already). They tell you to use the 720Ohm resistor between W1 and Common when power stealing, but that is only to dissipate potential voltage overages. There is no logical explanation to open the Rh relay when power stealing, none!

To net it out in summary;

When using Power Stealing, the thermostat will charge the Rh connection even when calling for AC.

This is an engineering flaw on the C4 thermostat and likely the reason so many dealers bitch about C4 TStat installations. This is NOT standard practice for thermostat behavior and any HVAC specialist will tell you this. If the C4 thermostat didn't do this one thing, it would have installed just fine... The bottom line advice I can give is that you must have a COMMON lead on your HVAC system to use the C4 TStat, or run it using BATT only and be prepared to replace the battery several times a year.

Secondly, while C4 TStats can operate independently of a C4 system, you CAN'T program them independently other than to turn them on or off, or set a basic temp hold. The only way to get to the 7 day programming is through the Director UI... and the only way to program startup times, cool off periods, and other run time tuning is to PAY A DEALER. STUPID! I want to un-ring this bell so very badly. I would NEVER recommend a C4 TStat.

Sorry to hear about your issues. It could be a compatibility issue. You may wish to contact your HVAC manufacture to verify that 3rd party units can be used.

Also you don't have to use power stealing. In fact it has been discussed here for years, that if you can use a common power wire to use it and not to use power stealing.

FYI, my C4 tstat uses a common power wire and it runs perfectly. I also have a business with four tstats running completly seperate zones, also not using power stealing, so I know that it can be done.

Also if you have CHE, you can program your tstat any which way you wish.

Hopefully you, your dealer and the HVAC guy can get your situation resolved.

[c44me]

you aren't alone. took me 3 tries to install mine.

[CFUG]

OK, I'm alone then. A few wires, a few minutes each. On to the next job. And, you don't even need CHE to program. Ever wonder what that little rectangle is top right on the therm. screen on a TS? If you need to upgrade then upgrade.

[chicagoskiguy]

As an FYI, I have a friend that purchased a Nest, and tried to replace a Bryant Evolution Tstat. He spent many hours on the phone with Nest, they sent out an HVAC guy, and ended up sending the Nest back yesterday.

[drousso]

Sorry to hear about your issues. It could be a compatibility issue. You may wish to contact your HVAC manufacture to verify that 3rd party units can be used.

Also you don't have to use power stealing. In fact it has been discussed here for years, that if you can use a common power wire to use it and not to use power stealing.

FYI, my C4 tstat uses a common power wire and it runs perfectly. I also have a business with four tstats running completly seperate zones, also not using power stealing, so I know that it can be done.

Also if you have CHE, you can program your tstat any which way you wish.

Hopefully you, your dealer and the HVAC guy can get your situation resolved.

Yeah, me think my original post stated the need for a common because power stealing doesn't work. Don't need to call my HVAC guy, he was the one that discovered the flaw with C4. Read my post again, the net part. It's a design flaw and as a result the homeowner has to install a common, but frankly that's not as easy as Controlfouruserguy would have you believe.

So for a homeowner with no common, the only answer is run a common or don't use C4 TStats. That's pretty bad! I can buy $29.00 TStats that work super without a common! My Honeywell TStats are aftermarket from Home Depot, and they worked like butter at half the cost of C4 without a common I might add!

Real issue is that C4 guys could fix this in a snap! But don't.. Just don't open the Rh relay when power stealing is enabled and Rc is called. Doh! Why they do this is a mystery.. But it is the reason these units don't work in power stealing mode. Simple simple simple.

[thecodeman]

Your $29 thermostat also doesn't have a zigbee radio that allows it to interop with the automation system. I'm no hvac expert or control4 product engineer but if I had to guess, the main need for the common is to power the zigbee radio. Just my opinion. Most times we have to use a third party stat since C4 currently doesn't support multi stage fan speeds.

If you want pretty thermostats get nest. A Swiss army knife stat that's ugly and doesn't yet integrate is Radio Thermostat. Somewhere in the middle is Control4.

[RyanE]

Control4 hasn't recommended power stealing for Control4 thermostats since 1.8.

Yes, it's an issue, and I apologize that it's caused pain for some of you.

The alternative is that you can just put a remote sensor in the tstat location, locate the thermostat itself by the equipment, and use the Control4 UI to set the thermostat.

You can set all values on the thermostat without a dealer, if you have ComposerHE. You can program it without a dealer, on a touchscreen.

RyanE

[LSDave]

Control4 hasn't recommended power stealing for Control4 thermostats since 1.8.

Yes, it's an issue, and I apologize that it's caused pain for some of you.

The alternative is that you can just put a remote sensor in the tstat location, locate the thermostat itself by the equipment, and use the Control4 UI to set the thermostat.

You can set all values on the thermostat without a dealer, if you have ComposerHE. You can program it without a dealer, on a touchscreen.

RyanE

Forgive me if i'm mistaken, but where does it show in the instructions of the tstat that its not recommended to use power stealing?

I understand that its better to use a common, and have done so in several installs. The few ive done powerstealing on, and had to call support about a question i had.. No one said that it shouldn't be done. I think by including the power stealing instructions with the t-stat, it would imply that you recommend that its a viable option to install it.

And if its not recommended, it would be really nice to know why not.. and the technical reasons behind it.

[ichbinbose]

Control4 hasn't recommended power stealing for Control4 thermostats since 1.8.

Yes' date=' it's an issue, and I apologize that it's caused pain for some of you.

The alternative is that you can just put a remote sensor in the tstat location, locate the thermostat itself by the equipment, and use the Control4 UI to set the thermostat.

You can set all values on the thermostat without a dealer, if you have ComposerHE. You can program it without a dealer, on a touchscreen.

RyanE[/quote']

Forgive me if i'm mistaken, but where does it show in the instructions of the tstat that its not recommended to use power stealing?

I understand that its better to use a common, and have done so in several installs. The few ive done powerstealing on, and had to call support about a question i had.. No one said that it shouldn't be done. I think by including the power stealing instructions with the t-stat, it would imply that you recommend that its a viable option to install it.

And if its not recommended, it would be really nice to know why not.. and the technical reasons behind it.

my guess by your post is that your a dealer or that you work for a dealer. My suggestion would be to spend some additional time on the dealer forum to learn more about best practices.

Keep in mind that manuals will tell you how to do something, but not always what is the best way.

[thecodeman]

Forgive me if i'm mistaken, but where does it show in the instructions of the tstat that its not recommended to use power stealing?

I understand that its better to use a common, and have done so in several installs. The few ive done powerstealing on, and had to call support about a question i had.. No one said that it shouldn't be done. I think by including the power stealing instructions with the t-stat, it would imply that you recommend that its a viable option to install it.

And if its not recommended, it would be really nice to know why not.. and the technical reasons behind it.

http://www.control4.com/files/dealers/documentation/21-0170_RevC_Thermostat_IG_Online.pdf

From Page 4:

IMPORTANT! The Wireless Thermostat has ‘power stealing’ enabled by default, however, it is recommended to power the Thermostat with a common wire. If power stealing is required, verify that your HVAC system supports power stealing prior to installation in this mode.

Changing this setting is described in Step 14, “Installation Instructions.” For more information about power stealing, see “Installing a Bypass Resister to Enable Power Stealing on a Wireless Thermostat” later in this document.

NOTE: The Wireless Thermostat requires power from the HVAC system to maintain regular communication with the Controller.

Pre-Installation Considerations

Using a Common Wire vs. Power Stealing

The Wireless Thermostat can be configured to operate in a ‘power stealing’ condition when there is no availability of a dedicated common wire. However, Control4 recommends using a dedicated common wire whenever possible. With some HVAC systems, power stealing can result in system contention between the Cool and Heat Modes, and will render the HVAC system inoperable. To aid in resolving this issue, a 270 Ohm 3 Watt Axial resistor is included with the packaging of each Wireless Thermostat. This resistor is intended to be installed between the W1 and the Common terminals inside the HVAC system. The resistor, when properly installed, will lower the risk of causing contention when the Thermostat is actively working in the Cool mode. Many HVAC systems will not tolerate a power-stealing Thermostat even with the 270 ohm resistor installed properly. In this case, a dedicated common wire is a requirement for proper functionality.

NOTE: The battery is used for backup purposes only.

[ILoveC4]

Well, LSDave, there you go =)

[RyanE]

I also spoke somewhat out of turn. This is what happens when I comment on something I'm not directly involved in.

What I was thinking of was no 'battery only' use, not power stealing. In *some* situations, power stealing will work, but it is always preferred to use a common wire if possible.

Sorry, I'm on a business trip and not getting much sleep. :|

I apologize for the misunderstanding.

RyanE

[LSDave]

Thanks for the quotes guys, but i had asked where is says it ISN'T recommended to power steal. I know it recommends to use a common wire, and i have done so for the majority of jobs.

I also do read the dealer forums and see that a lot of people have been frustrated with the thermostats. And in some cases, people have wasted soo much time to try and get power stealing to work that they could have run a common wire, then patched and painted any holes they made in drywall in order to get that common wire run.

I think there needs to be more TECHNICAL information included on how the power stealing works...... how to TEST if it can work.

The one bit of info that I got from a tech at Control4, was to remove the battery and hook up the t stat in power stealing mode. Then see if it powers up and functions... And if it does, then the HVAC "should" support power stealing. He also recommended ALWAYS installing the bypass resistor if using power stealing.

There is soo much information all over the place with this issue, it would be nice if it was all in one Knowledge base document.

[thecodeman]

I agree.

[CFUG]

I really like how a thread about the Nest turns into a tech discussion about a C4 stat. With no moderation here this is what happens, shear disorganization.