Nest thermostat wiring issue

tamer

Hi All,
I'm trying to install nest3 and seems no power coming to the unit.. I connected the B wire to C , but it didn't do the trick.
I see "C" on Zone 1 panel empty.. I can put un-used wire there and run it to the thermostat, but where should I put the "B" wire if I do that?
It's forced-air AC/heat - 1 furnace - uses LP - No backup system.
Thanks in advance.

Alan (California Radiant) Forbes

It looks as though your old thermostat was wired for a heat pump with terminals "O" and "B" operating the reversing valve although the "O" and "B" are usually not used together.

tamer

@Alan (California Radiant) Forbes thanks for your reply.. so what do you recommend?

ratio

Looks like you're going to need to read the manual for the zone control board. It's possible that the board needs both an O & a B signal to operate, but it's also possible that someone just landed both because it has both terminals to allow it to use either style of heat pump thermostats. If one can be freed up, just switch it over to C.

Ironman

On a heat pump stat, the "O" terminal energizes the reversing valve in cooling (most brands operate this way). The "B" terminal is energized when the stat is set to "Heat" and energizes the reversing valve in heating (Rheem and Bosch use this).

You should be able to move the wire from "B" to "C" on the board, but no guarantee without seeing the schematic for the board.

By the way, the Nest is the worst piece of junk being passed off as a thermostat that there is - especially when used with modulating equipment.

EdTheHeaterMan

Ironman said:

By the way, the Nest is the worst piece of junk being passed off as a thermostat that there is - especially when used with modulating equipment.

@tamer, Don't worry about Ironman's assessment. There are thousands of Nest users that have no problem with them. Every once in a while, the thermostat is installed on a system that it is not compatible with, and the purchaser comes here for help. So we only get to see the problem ones here, which makes for 100% of the people with nest thermostats herein are "Problem" thermostats. Add to that fact that some service personnel who have had a bad experience with a Nest thermostat are going to vent their inability or unwillingness to learn how they work with the "That is a piece of Junk" comment you see above.

I am looking into your issue now and would like some more information. What heating/cooling system is the EWC control attached to?
And what is the brand and model/part number of the original thermostat the Nest replaced? (Looks like a Honeywell)

pecmsg

X2 on NEST being the worst stat on the market!

EdTheHeaterMan

After reviewing the manufacturer's instructions for the EWC control panel, it appears that you must use only the EWC thermostat for your system. Unfortunately, the Nest thermostat is not compatible with the wiring of that particular EWC control panel.

As indicated in the instruction manual on page 6, the only compatible thermostat for Zone One is EWT-725 or EWT-601-2 and there are no WiFi thermostats available.

In order to get any WiFi capable thermostat to work in your system, you must replace the EWC control panes with another brand.

Ironman

@EdTheHeaterMan
I'm very familiar with the Nest and that's why I hold the opinion that I do.

You don't know me well enough to state that I have "an inability or unwillingness to learn" because you hold a different opinion. We can disagree without such intellectual bigotry.

EdTheHeaterMan

I'm sure the Nest thermostat people feel the same way

"worst piece of junk" could be more tactfully stated as "I'm not a fan" or "I recommend brand X"

Such intellectual intercourse is less helpful to the OP who just made a significant purchase or received a gift from a loved one. I would suggest that Thermostatic Bigotry has no place here either.

The comment was not to make anyone in particular offended but to perhaps ease the concerns of the party with the problem. Strong opinion on the subject of Nest Thermostats are well known to the regulars on The Wall. The new and first-time contributors are not as well versed in that debate herein. I was just using the exact words of one person to emphasize the opinion of one side of the argument to compare it with the opposing point of view. I will endeavor to be more understanding of both sides in the future.

Jamie Hall

Permit me to add a word or two here -- with particular, but not unique, relevance to the Nest. When we are designing and installing a heating system, we need to remember that it is just that: a system. All the components must be chosen to work well together and to accomplish the desired goal -- which, for heating, is simple: the comfort of the occupants with enough convenience. The occupants should, in theory, not have to worry about how or why it works, but only that it does work.

Now. How does this apply to a specific bit of hardware, in this case a thermostat? Simply this: it is almost impossible to design a bit of hardware -- in this case a thermostat -- so that it works equally well with all types of systems in all situations. In virtually all cases, the design in question will work best with certain systems, moderately well with others, and --usually with some effort -- at least adequately with others. The Nest is a remarkably good case in point. It is, in fact, a very well designed home automation device, intended to control a heating or heating and cooling system and offer a great deal of flexibility in terms of learning the occupants desires and habits, and it does this very well indeed -- for systems which respond rapidly and which have the necessary power supply and control wiring to which it connects. It can be tweaked to work adequately with slow responding systems (up to a point -- radiant floors are quite beyond it, unless it is almost completely disabled) but no more than adequately -- to use an analogy from a different field, one can go grocery shopping in a Peterbilt, but would you want to? It usually can be made to work adequately in systems which do not have the wiring connections which it needs (not always -- if the on cycle of the thermostat is too long, it will fail), but again with considerable effort.

In an installation which is either new, and includes the necessary wiring and compatible system controls, or is a pretty complete rebuild, likewise, and which is forced air (air to air heat pumps, forced air furnace, etc.), it is not itself a bad choice (the security and privacy matters are a separate consideration). In an installation where it, and only it, is installed for whatever reason, without corresponding changes in the rest of the system, getting it to play well with the rest of the system can be remarkably difficult, as we have seen in numerous threads.

Perhaps the reason why some heating professionals take a somewhat dim view of it is that it is heavily advertised as a "plug and play" device, and it may be purchased and installed by people who have little knowledge of the rest of the system. When it doesn't work, the pro. is called ("my heat doesn't work right") and is tasked with getting it to work -- somehow -- with the rest of the system.

HVACNUT

The use of B and O in this case is power open/ close the damper. That's an old master/slave zone system. Time to upgrade. 

tamer

HVACNUT said:

The use of B and O in this case is power open/ close the damper. That's an old master/slave zone system. Time to upgrade. 

@HVACNUT you are correct. So, what's your recommendation.. what's the easiest way to upgrade, and what to do about the master-slave zones?

EdTheHeaterMan

Nest thermostat may not have the option that the EWC thermostat has built into it. There is a terminal with a * that can be programmed to do other functions. Let me look into those other options for a moment.

ratio

You should be able to use a Honeywell HZ311 zone panel (max 3 zones, 1 heat 1 cool) with your current zone dampers & furnace. Note the terminals on the zone damper wiring, it'll be much easier if you don't have to experiment! You'll likely have to replace the slave (zone 2) thermostat with a modern one as well; and you may need to add a bypass damper to the furnace.

The new panel will gain you true changeover operation—either thermostat will be able to call for the mode it wants & the system will change as needed (doing The Right Thing with the dampers).

EdTheHeaterMan

Is this a heating-only system?

Is there Air Conditioning involved?

EdTheHeaterMan

There appears to be a workaround for you to be able to use a Nest thermostat. It would require a Double-Pole-Single-Throw switch to be operated manually at the change of season. This means that you will manually flip a switch from Cool to Heat before you can operate the system.

If the switch is in Cool mode, you will not be able to operate the heat even though the NEST thermostat says you can. The same is true for Heat mode. The thermostat will be able to be programmed to Cool mode but the system will not operate.

This will be confusing in the fringe season (Spring and Autumn) if it is cold one week then hot the next week You will need to go to the switch that you will mount on the heater near the panel and manually switch from heat to cool.

If this makes sense and you are interested in trying to make it work, then I will make up a diagram for you

Let me know. The NEST will not have the capability to do this for you because the O/B terminal does not work the same way on your existing thermostat.

It is a little inconvenient but, it is what it is if you don't want to spring for a new zone control panel. The switch will be around five or ten bucks at a hardware store or electronics hobby store.

EdTheHeaterMan

ratio said:

You should be able to use a Honeywell HZ311 zone panel (max 3 zones, 1 heat 1 cool) with your current zone dampers & furnace. Note the terminals on the zone damper wiring, it'll be much easier if you don't have to experiment! You'll likely have to replace the slave (zone 2) thermostat with a modern one as well; and you may need to add a bypass damper to the furnace.

The new panel will gain you true changeover operation—either thermostat will be able to call for the mode it wants & the system will change as needed (doing The Right Thing with the dampers).

How much does that cost him? Rhetorical... answer not required.

I think the following would be less expensive.

ECW has this diagram in the instruction manual
It is a summer/winter switch and a fan switch that can mount on a standard switch or junction box. All the connections are low voltage.

For the cost of a small SPDT switch from the hardware store, you don't even need the electric box to mount the EWC optional remote control switch. It is safe and economical. All the low voltage wiring is completed inside the EWC control panel.



The NEST becomes the master thermostat for the "Fan On" function and the Summer/Winter switch is mounted on the control panel like this


I would have charged you big bucks to do that for you as a Nest Pro. just 2 years ago. Here I am giving it away for free.
Retired and loving it
Mr.Ed

tamer

EdTheHeaterMan said:

There appears to be a workaround for you to be able to use a Nest thermostat. It would require a Double-Pole-Single-Throw switch to be operated manually at the change of season. This means that you will manually flip a switch from Cool to Heat before you can operate the system.

If the switch is in Cool mode, you will not be able to operate the heat even though the NEST thermostat says you can. The same is true for Heat mode. The thermostat will be able to be programmed to Cool mode but the system will not operate.

This will be confusing in the fringe season (Spring and Autumn) if it is cold one week then hot the next week You will need to go to the switch that you will mount on the heater near the panel and manually switch from heat to cool.

If this makes sense and you are interested in trying to make it work, then I will make up a diagram for you

Let me know. The NEST will not have the capability to do this for you because the O/B terminal does not work the same way on your existing thermostat.

It is a little inconvenient but, it is what it is if you don't want to spring for a new zone control panel. The switch will be around five or ten bucks at a hardware store or electronics hobby store.

That will be great! I'm OK with adding a switch if you give me the details. .. This system is AC and heat. Heat uses propane and AC has outside compressor. 1 furnace for both , forced air. with master-slave zone. I have only 2 zones in the house.
I was able to install the nest thermostat on the slave one because it had only 4 wires. But the master is the issue.
Currently, the master thermostat is haneywell

tamer

EdTheHeaterMan said:

ratio said:

You should be able to use a Honeywell HZ311 zone panel (max 3 zones, 1 heat 1 cool) with your current zone dampers & furnace. Note the terminals on the zone damper wiring, it'll be much easier if you don't have to experiment! You'll likely have to replace the slave (zone 2) thermostat with a modern one as well; and you may need to add a bypass damper to the furnace.

The new panel will gain you true changeover operation—either thermostat will be able to call for the mode it wants & the system will change as needed (doing The Right Thing with the dampers).

I think the following would be less expensive.

ECW has this diagram in the instruction manual
It is a summer/winter switch and a fan switch that can mount on a standard switch or junction box. All the connections are low voltage.

For the cost of a small SPDT switch from the hardware store, you don't even need the electric box to mount the EWC optional remote control switch. It is safe and economical. All the low voltage wiring is completed inside the EWC control panel.



The NEST becomes the master thermostat for the "Fan On" function and the Summer/Winter switch is mounted on the control panel like this


I would have charged you big bucks to do that for you as a Nest Pro. just 2 years ago. Here I am giving it away for free.

you are the best @EdTheHeaterMan

HVACNUT

I agree with @ratio. Install an HZ311 panel.

ratio

I like the though-free operation of a new zone panel, but it would be literally 10-20x more $$$ to go that was, & no guarantee that a bypass wouldn't be required, which would double the cost again. If you're ok with flipping the switch a few times a season, go for it!

tamer

EdTheHeaterMan said:

Is this a heating-only system?

Is there Air Conditioning involved?

ratio said:

I like the though-free operation of a new zone panel, but it would be literally 10-20x more $$$ to go that was, & no guarantee that a bypass wouldn't be required, which would double the cost again. If you're ok with flipping the switch a few times a season, go for it!

Thanks, @ratio for your reply - I'm just trying to understand why I might need bypass.. I already have 2 zones master/slave.. or master/slave zones mean master will work all the time? excuse my ignorance here .. thanks

EdTheHeaterMan

Master, Slave in your case refers to the thermostat that has the ability to switch from heat to cool and turn the fan from on to auto. The master can also check the temperature of the area it is located. The slave thermostat(s) can only react to temperature adjustment with no control over the system function or fan function.

The temperature sensing is independent and works the same way on either master or slave.

With the suggestion I made in the PM to you, your master functionality is at the optional switch on the zone controller. That workaround essentially makes both thermostats Slave thermostats because the master functions are enabled by the optional "remote" switch.

tamer

Got it! thanks @EdTheHeaterMan !

EdTheHeaterMan

What some are not realizing in your system (that has worked to your satisfaction for years) uses the same logic with the remote switch as it does with the Master Thermostat. Only one location can be used to change over from heat to cool. If it is important to have the switch in the same location, the same wires can be used to put the Heat/Cool switch at the thermostat location. The control logic does not change.

The WiFi function of changing from heat to cool is not available with the NEST system or any other system. But everything else is.

ratio

WRT the bypass, it's purpose is to give the unit a place to dump any extra air that it can't cram down the duct to the zone that's calling. Furnaces must have a certain amount of air going through them for proper operation—too little & you run the risk of overheating (& possibly melting something!) in the winter time; & freezing up in the summer time.

It may or not be required, depends on how everything is sized, but I sure wouldn't want to recommend you make some changes & have you find out half-way through that you need to do a lot more work that I didn't mention.

mzab123

Ed the heating guy - great work around. Ed, can you or someone else show me a little more clarity when it comes to hooking up the switch. The switch has 4 poles and I want to make sure that the wires go in the right place. This is the switch I ordered.





One little caveat, the switch is backwards to the wires. I read this in the amazon review, "Nice heavy duty switch. I spent hours chasing my wires trying to figure out why my lights were not turning on. Switch is wired backwards! Left on is right wire right on is left wire! Had a few choice words once I figured out I had everything correct and just had to flip switch other way. Not real happy about the wasted time. I wish it came with a diagram or at least a pic of the circuit or something!! It in now and looks good but what a pain!"

Any help with the wiring of this switch would be much appreciated. I am a nube when it comes to this. Btw, Ed it says you are from South Jersey, I just moved down there - what town do you call home.

Thanks,

Mario

Gkrynick22

Correct me if I'm wrong, but wouldn't upgrading to a NCM-300 be the easiest route?   Sure it's almost $200, but you have the luxury of simply moving the wires from the old one over to the newer one using the exact same terminals. Easy "plug and play" swap with no other add-ons necessary (unless you are missing "c" wires at one of the thermostats.  

mzab123

"I like the though-free operation of a new zone panel, but it would be literally 10-20x more $$$ to go that was, & no guarantee that a bypass wouldn't be required, which would double the cost again. If you're ok with flipping the switch a few times a season, go for it!"