Definitive 1-pipe steam thermostat? (under $250)

higgins17

Hi All,

First post here. Thanks to all in this community who give back so much, especially in the steam forum!

New to my house with a 1 pipe steam system but I grew up with steam and have spent hours reading just about everything there is to read about steam thermostats (in this forum and elsewhere). My older system is balanced as well as I believe it can be, but I long for more control via mobile devices and for the shoulder seasons.

The facts:

• 1 pipe steam system in a 2 story cape
  
• Thermostat on 1st floor
  
• No c-wire (2 wire presently, would need to rewire for 4, probably not too big of a deal)
  
• Lots of overrun with current old Honeywell thermostat (needs adjustment, but house/system is also generously outfitted with radiators)
  
• Would like to take advantage of smart thermostats that are wifi capable, use outdoor temps, learn to avoid overshoot.
  
• Like the idea of manual scheduling and on-demand changes, but not specifically interested in thermostat learning my behavior
  
• Like the idea of data logging (I'm a data geek, but don't want to have to get too obsessed to have a comfortable house)
  

My current leanings:

• Ecobee 3 (the best?) - seems good but unsure if it's good at learning to avoid overshoot (have read that it may not do this well)
  
• Honeywell Wifi Smart Thermostat (strong but limited?) - a bit older but a contender
  
• Nest (ok with steam? privacy issues?) - seems good but have read mixed reviews about using with steam
  
• Honeywell VisionPro (good, but poor support?) - Difficult to tell where this stacks up
  
• Emerson Sensei (a less expensive alternative?) - anyone own this?
  

What do you all think? It's very difficult to get a gauge on what thermostats actually deliver convenience and results while not requiring gobs of extra hassles. At the end of the day, I'd love to just be able to set a thermostat for 1 hour cycles, have it look at the indoor and outdoor temp once an hour, heat the house to the appropriate temp, come back the next hour and do the same thing. What solution will best help me to do this?

Thanks!

J

KC_Jones

We all have our opinions on this one and I am sure you will get a bunch of them, so here is mine. First I would take nest off the list, actually forget it even exists. I have a Honeywell VisionPro (not a WiFi version) and for a thermostat I like it. It will somewhat address the overshoot you speak of as it has a learning function. It isn't perfect, but it's an improvement. I have read some good things from people on here about the Ecobee, but no personal experience. That's about all I know, I have a feeling you might get a lot of votes for the VisionPro as quite a few of us use them on our steam systems. One thing to keep in mind (if you don't already know) is the CPH setting is important for steam so you really want a thermostat that has that control or some derivative of it. It's important because it allows longer run times on the boiler which means you get steam to the radiators. Honeywell has this, Nest doesn't and I am not sure about the rest.

Jamie Hall

Me? I'd use the VisionPro. And do. There's a bit of a problem sometimes with overshoot -- by about a degree -- on coming out of the night setback (3 degrees Fahrenheit). Otherwise... it couldn't be simpler.

I don't see the point of an outdoor reset for steam. Hot water, yes -- one can change the circulating water temperature that way, so the circulation is pretty constant. But steam? That puppy is either on or off. The VisionPro works well at learning how early to shut the boiler off to avoid the overshoot. But then, so does a T87, if it's properly adjusted...

I'd avoid the Nest for steam -- I've not heard much good about it for steam.

higgins17

Thanks KC_Jones and Jamie!

Looking forward to a couple more comments! The VisionPro definitely seems to be an early favorite, but I'm really inclined to hear more about the Ecobee 3 or even the Honeywell Prestige series, both of which I read have nice remote capabilities to focus comfort levels on where the remote is located.

I don't want to obsess about this, but if I'm going to go through the trouble of running wires, I'd love to experience some fairly significant improvements in comfort and economy.

nicholas bonham-carter

Don't forget to search for the eco steam control here.
One nice thing about the Visionpro is its remote sensor, which only needs 2 wires.
Mount the Visionpro (wifi version) in the boiler room, and the remote sensor could be in the old thermostat location.--NBC

higgins17

Nicholas,

Interesting you mention eco steam. I had just kind of written it off for my use due to what looked like a high price to purchase and complexity of install. If that's not the case, someone should definitely let people know!

Thanks!

vaporvac

I have the Honeywell wifi in my tag. It works really well avoiding any overshoot and I use the wifi much more than I would have thought. It also send me notices if the temp goes too low/high or if power goes off. It wasn't at all expensive. It would be nice to have a remote sensor and screen, but not necessary. It's also useful if one has a two stage gas valve or twinned boilers as I do.

NYplumber

Honeywell Pro8000 with interface modula and range extender. Add a second sensor and you can either average the two readings or just use the sensor. Totally wireless.

nicholas bonham-carter

I would like some of the features of the EcoSteam, but as other non technical people may have to run the system, I am afraid of the learning curve.
I have the Visionpro, with wired sensor in the most exposed upstairs bedroom, and that seems to work best. I am not using regular setbacks, and can therefore keep the constant setting lower, (65 degrees).--NBC

hboogz

Higgins and all - Just to address a very basic question. In order to use a VisionPro you would need to run a new thermostat 2 pair cable down to the transformer? Which gauge/cable type?

I'd love to also get wiFi ability for my 1-pipe steam system but have always paused on the electrical aspect.

Jamie Hall

Depends on the specific VisionPro. Some models need a C connection. Some are pure battery -- the latter only need the two wires. If you're going to have WiFi in there, you're going to need the C to power it.

higgins17

Thanks @Jamie Hall, @hboogz - This is definitely the logical next question - thanks for asking it!

In my case, my boiler circuit board appears to have the ability to run 4 wires. Only 2 are currently hooked up and presumably go straight to the old school thermostat.

John Mills_5

If you have a Vision Pro and EIM, you don't need any wires. The VP will run off battery and transmit wirelessly with the EIM. To save on batteries, 2 wires to the EIM will power off 24V. The EIM will need 24V R&C and W to call for heat. The indoor sensors are wireless with the new VP and can average the temp or read only from 1 sensor. There's the internet gateway for WiFi and the remote control which acts as a sensor. You tell it whether it senses or the stat. Not sure what more the Prestige would do for a steamer. It would require 2 wires for power, can't run off battery.

The new VP WiFi would require a common as would the Prestige WiFi.

We sell a lot of the Ecobee3 but for heating & cooling, never a boiler. Not sure you have cycle control so may overshoot more than the Honeywells.

higgins17

@John Mills Thanks for that info.

So, to be clear, the EIM would be installed down near the burner controller? And that becomes the central control to the system that then takes direction from the VisionPro (which is running on battery?)

How do the VisionPro batteries not expire quickly with this configuration? What function does the VisionPro now serve? Communicating settings to the EIM?

Last, I like that there are now wireless sensors that communicate wireless with the VisionPro, and that's a nice addition!

Thanks for the good discussion all!

KC_Jones

I was just reading up on the remote sensors the other day. It looks like what happens is the remote sensor takes the place of the sensor in the thermostat. I think you can hook up multiple sensors and average the temp and the thermostat will fire the boiler according to this average. I think what was mentioned for ease of install (if you don't have the "C" wire) is to mount the thermostat near the boiler so you can more easily run the "C" wire then use remote sensors in the house.

higgins17

@KC_Jones : So it sounds like the best play is really to buy a length of 5-wire cable and run it from the boiler to the thermostat. That will still leave me with a 4-connector setup on my boiler control board.

Is the c-wire hookup included on most 4-connector setups or am I likely to need another piece of hardware?

Thanks again - I hope there are others that will find this helpful! Perhaps I can consolidate all of this info into a table/flow chart.

Also, if there's a great book or article that already covers this pertaining to older heating systems, please let me know and I'll read up about it there!

-J

ChrisJ

I'm using a Visionpro 8000, which the Common is optional but I ran it so I could have a continuous backlight. Not only that, but it makes the batteries last much longer.

The VP alone is kind of finicky in my opinion and does some weird things. However, I've found the Ecosteam is perfect at keeping it in line.

A perfect example is if I set my VP to 2 CPH and just let it run, over time it slowly changes to the point it seems like it's back to the same as it was on 1 CPH. With the Ecosteam this doesn't happen. It runs 2 cycles per hour very well and has zero overshoot even after a large recovery.

My vote would be for a VisionPro and if possible an Ecosteam to go with it.

I owned a Nest for an hour. I returned it because it locked up for no apparent reason within that first hour. I won't tolerate that on my heating system especially at that price tag.

ratio

There are several recent threads about wireless Honeywell stats - search for "EIM". IIRC all the Wi-Fi stats are going to need a common, the 802.11 radios just suck too much power. The 8000 needs a common for RedLINK, the 6000 does not.

I try and use Honeywell stats everywhere I can - they reduce callbacks - but they don't expose as much of their internal algorithm as some others.

higgins17

Perhaps I'm in the minority, but the fact that there isn't a definitive guide for converting a 2 wire system to a wifi thermostat boggles my mind. Of course, I have some specific preferences for steam performance, but I'm very surprised there isn't a clearer solution out there!

There are tons of knowledgable all-stars on this forum and I'm still not clear as to what I need to do to have a reliable, well performing, single pipe steam thermostat going from a 2 wire system to either an updated 2 wire thermostat or to a 4 wire system!. No wonder people have ripped out their systems and started from scratch!

ChrisJ

Yes Higgins that's why people rip out entire heating systems because of a lack of a ground wire.......

SteamedInWharton

I had bought an 8321 and an EIM and then afterwords found out that my ancient armored, cloth insulated t-stat cable was in fact 3 wire! An extra blue wire had been hiding there all along. I wired up the EIM any way and connected an external transformer to power the R&C lines. The boiler gets Rh and W and all of the R's are isolated (jumpers removed).

higgins17

@SteamedInWharton Thanks for that input!

Crazy I know, but as far as I can tell, the ecobee has done the best job I've encountered of marketing their system as they've made it clear they have a Power Extender Kit to convert a 4 wire system to confidently power their thermostat. I'm more than willing to rewire if I'm confident I can get what I need from my existing control board.

It's clear to me that most, if not all wifi enabled thermostats will need more power that what AA's can provide, so when looking for a thermostat, I'm looking for certainty that I'm getting all of the parts needed to finish the install!

Sincere thanks to all who have contributed to this thread and others that have led to my knowledge here.

vaporvac

SteamedInWharton said:

I had bought an 8321 and an EIM and then afterwords found out that my ancient armored, cloth insulated t-stat cable was in fact 3 wire! An extra blue wire had been hiding there all along. I wired up the EIM any way and connected an external transformer to power the R&C lines. The boiler gets Rh and W and all of the R's are isolated (jumpers removed).

YOu beat me to it. I discovered the same thing! I even bought the replacement wire!

KC_Jones

I am a bit confused by the confusion on this?! To power the thermostat you need a third wire from the "C" terminal, it's a ground wire to complete the circuit. I doubt any thermostat manufacturer is going to give you more direction than that since there are literally hundreds if not thousands of different heating systems out there and they can't tell you exactly what to do in your particular application. What you can do is look at the manual for your boiler and see where the "C" terminal is and that's pretty much all you need to know. I did this on mine and it was literally about 30 seconds to figure out. I guess I am not understanding your question to be able to accurately answer it?! I am also confused by your 4 wire comment? My thermostat is fully powered from the boiler and I only have 3 wires, what is the 4th wire?

ChrisJ

KC_Jones said:

I am a bit confused by the confusion on this?! To power the thermostat you need a third wire from the "C" terminal, it's a ground wire to complete the circuit. I doubt any thermostat manufacturer is going to give you more direction than that since there are literally hundreds if not thousands of different heating systems out there and they can't tell you exactly what to do in your particular application. What you can do is look at the manual for your boiler and see where the "C" terminal is and that's pretty much all you need to know. I did this on mine and it was literally about 30 seconds to figure out. I guess I am not understanding your question to be able to accurately answer it?! I am also confused by your 4 wire comment? My thermostat is fully powered from the boiler and I only have 3 wires, what is the 4th wire?

Fan.

higgins17

Thanks all. Seems pretty simple - I think what makes it more complicated is that some thermostats claim to have wifi capabilities without a c-wire (read: Emerson Sensi). Unless someone says otherwise, it sounds like there can be complications relying on wifi without a c-wire (correct me if I'm wrong here).

Bottom line from what I'm hearing:

1. Want wifi and full choice of thermostats? Install c-wire and take your pick (for steam I'm hearing Honeywell VisionPro or Ecobee 3)
   
2. Want wifi and don't want to install c-wire? Trial and error yourself or find a specific model and configuration that's recommended by the pros on here (Honeywell VisionPro 8xxx with EIM seems to be one of them)
   
3. Don't care about wifi? Install a non-wifi, battery-only powered thermostat (like Honeywell 6xxx series) that has a reasonable featureset including the ability to learn how to prevent overshoot.
   

ChrisJ

Here's my opinion which is probably worth almost nothing.

The Nest claims you don't need a common "c wire".
Any "smart thermostat" aka computer should have a common in my book.

Most steam systems can probably get away without it more than a modern system though. For example a radiant system sized well may run non stop for a long time on extremely cold nights. This could completely drain a smart thermostat's power as it never gets a chance to "steal" power because the system is never off.

Chances are, a steam system will never see that scenario.

None of them will learn to not overshoot because conditions change. If you have near steady conditions for a few days it'll learn but as soon as the weather changes it needs to re-learn again.

Want to keep things simple and affordable?

http://www.supplyhouse.com/Honeywell-TH5110D1006-The-FocusPRO-Non-Programmable-Digital-Thermostat-Premier-White-4087000-p

vaporvac

higgins17 said:

Don't care about wifi? Install a non-wifi, battery-only powered thermostat (like Honeywell 6xxx series) that has a reasonable featureset including the ability to learn how to prevent overshoot.

My Honewell RTH6580WF ie 6xxx, is wifi and direct wiredie. no batteries. It needs a C wire which you may have. If you have other features, you'll need more wires.

RomanGK_26986764589

I have Honeywell Focus Pro 6000. Seems to be working fine. It also has CPH 1-12 CPH setting. I keep mine on 2CPH. Evens the temp in my house a bit.

vr608

This thread inspired me to finally replace my old Chronotherm 3 with a Focus Pro 6000! Got a great deal on Amazon earlier today, now the hard part will be getting it wired to the C wire on my boiler...

hboogz

While I'm at it why not ask the million dollar question for us noobs: What exactly is a C wire? Where does this C connect down in the boiler room? Say if you only have a transformer and basic boiler controls? Eg lwco, pressuretrol, auto feeder and chimney damper?

KC_Jones

The C wire is the neutral connection in the 24 VAC boiler control circuit. Since the thermostat is just a switch it typically only needs the hot and switch wires run to it (no different than a light switch on and off). With the newer thermostats with WiFi and other features you run the Neutral from the transformer up to the thermostat and it can then be powered up instead of using up batteries like crazy. I can tell you even with basic functions they can eat up some batteries so it's nice to power them from the boiler. On the vision pro it also allows you to keep the pretty green glow on all the time, which I think just looks cool.

Mark_125

Similar to what hboogz said. In my basement I have a 24V transformer which goes:
Wall -> T-STAT -> P-TROL -> LWCO -> Burner -> Wall.

Do I take a 2nd wire from the neutral on the transformer and run that as the C wire ?

ChrisJ

Mark said:

Similar to what hboogz said. In my basement I have a 24V transformer which goes:
Wall -> T-STAT -> P-TROL -> LWCO -> Burner -> Wall.

Do I take a 2nd wire from the neutral on the transformer and run that as the C wire ?

You'd need to give a picture of the schematic to your boiler. I just connected to the ground on my boiler as that's what the neutral in the system was. I'm sure many boilers are different though. The manual to your boiler should having a wiring schematic for it.

hboogz

While stripping 6 layers of paint off the side stairs of the house I came across what was a telephone wire, snipped it and called it a win. Turns out that was the Tstat wire! Don't know who decided it would be a good idea to run the tstat wire along steps, but what's done is done. So, now that I have to run a new line, do I use 18/5 to give me the possibility of running a WiFi Tstat? Or 18/8 ?

Thanks,

Harry

ChrisJ

I ran Belden 18/4 because it's what I had on hand but I only needed 3 as I'm using a common.

Anything 18AWG should be fine as long as it's rated for 24VAC or better and I recommend something with fairly durable insulation.

JUGHNE

I would second Chris's HW t-stat suggestion only I only get the TH5110D1022 which has a larger screen which is easier to read if you believe your eyes will age.

hboogz

Chris and Jughne, Thanks for the confirmation!

NoreenClaire

@higgins17 I posted a similar question about t-stats right after you. Not sure where you are located, but if you live in MA there is a program available where you can get a few of the t-stats you list for a significant discount PLUS free installation. Info can be found here: masssave.com/en/residential/offers/wireless%20thermostat%20and%20installation%20incentive

If you are not in MA, it may make sense to google incentives through your own state/energy provider.

Good luck, and thanks to everyone providing info on this post - it was very helpful!

vr608

Agreed, very informative post. I managed to install my FocusPro the other day, so far, so good.

Now I'm looking at an upgrade to the Vision Pro 8000 since I want to utilize the remote sensor capability; my attic bedroom is considerably cooler than the rest of the house and I'd like to average out the temperature extremes a bit better.

vr608

ChrisJ said:

Anything 18AWG should be fine as long as it's rated for 24VAC or better and I recommend something with fairly durable insulation.

Uh oh. I guess the 2' section of telephone wire I spliced in will need to be replaced.