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You Can't Set Cycles per Hour on a Nest Thermostat

I got an email ad for Nest thermostats today with an email address for asking questions.

You apparently can't program cycles per hour on this thermostat. (See attached reply)

- Rod

Comments

  • ChrisJ
    ChrisJ Member Posts: 11,985
    Nest

    Boooo!!! Hissss!!!!!



    :)
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Mark N
    Mark N Member Posts: 1,090
    Nest

    I don't know $249 for a thermostat. I watched the video who actually plays with their thermostat that much. I have steam I set it to 70 over a month ago. It will stay there till spring.
  • David Nadle
    David Nadle Member Posts: 624
    CPH ain't the only way

    I don't think the Nest is going to work out for other reasons, but the lack of a CPH setting only means that they're not using the Honeywell style P+I algorithm. The Nest does have a hydronic/steam setting, and it's entirely possible that it is capable of controlling a steam system as good as or better than a Honeywell thermostat. Whether its opportunistic, "learning" setback feature will be enjoyed by many is less certain. 
  • jpf321
    jpf321 Member Posts: 1,567
    edited December 2011
    i wonder if the nest...

    algorithm .. figures out that it costs waay more to recover in steam than to just leave it as it was before it setback (at least for setbacks less than 24hrs)...at which point you may as well have spent $15 on a round non-programmable wall unit.
    1-pipe Homeowner - Queens, NYC

    NEW: SlantFin Intrepid TR-30 + Tankless + Riello 40-F5 @ 0.85gph | OLD: Fitzgibbons 402 boiler + Beckett "SR" Oil Gun @ 1.75gph

    installed: 0-20oz/si gauge | vaporstat | hour-meter | gortons on all rads | 1pc G#2 + 1pc G#1 on each of 2 mains

    Connected EDR load: 371 sf venting load: 2.95cfm vent capacity: 4.62cfm
    my NEW system pics | my OLD system pics
  • Nest/Cycles per hour

    I saw your post regarding your steam radiator and Nest.  I noticed that you posted your comment in 2011.  Have they solved this issue? I have the same problem with my boiler.

    Thank you,

    Jason
  • ChrisJ
    ChrisJ Member Posts: 11,985
    Nest

    Has a setting called "True Radiant" which is said to be for radiant heat as well as radiators, though it doesn't specifically say which type. 



    Have not tried one my self and due to all of the reviews talking about software glitches causing problems I don't think I will be.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • AlexR
    AlexR Member Posts: 61
    can you set the swing or deadzone?

    Does it let you set the deadzone?



    My thermostat doesn't have a cycles per hour setting either, but setting a 2 or 3 degree deadzone achieves a similar result.  Using a 2 degree setting means that if the thermostat is set to 70 in heat mode, it won't turn the boiler on until the temperature drops to 68.  That effectively prevents more than one cycle per hour and it's a small enough change in room temp that you can't tell unless you look at the thermostat.
  • Jamie Hall
    Jamie Hall Member Posts: 17,164
    I suppose...

    that this thread is as good a one as any on which to pose the question I have about the Nest thermostat... which is...



    Why?



    As far as I can figure out, the only type of heat which responds fast enough to warrant moderate to large setbacks is forced air.  Radiant surely doesn't, and steam seems to tolerate small setbacks after a fashion, as does hydronic.  So it might be OK for forced air...



    but then...



    if you have anything temperature sensitive in the place, whether it's a plant or fine furniture or a piano, you don't want to change the air temperature much; a few degrees, that's all.



    So why, unless you are iFreak of some kind, would you have a Nest?



    Just askin'
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • David Nadle
    David Nadle Member Posts: 624
    "Learning"

    The supposed value of the Nest is that it incorporates a motion sensor and learns when you're home and not home to deploy setback. It seems to me if you have a high mass system like steam there are going to be many episodes where you'll be disappointed with the Nest's choices.
  • Joe V_2
    Joe V_2 Member Posts: 234
    Here is a photo of usage

    on a one pipe steam system in NYC.  Owner is happy with performance.  Boiler operates between 3 &4 hours per day.  I'll let the experts here exploit the pros and cons.
  • ChrisJ
    ChrisJ Member Posts: 11,985
    edited January 2013
    Yikes

    63F at night to 71F in the morning and then back down to 63F?  I consider my system to be pretty well matched and I wouldn't even consider a schedule like that.  I do a 3 degree recovery in the morning (67F to 70F) and then maintain until bedtime and then it drops back down to 67F.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Joe V_2
    Joe V_2 Member Posts: 234
    nest

    schedule
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,512
    Fluctuating temperature

    If the customer is happy with the performance, is the customer right? Most people with unbalanced steam systems have to rely on bumping up the temperature to get the cold spots warm, and maybe as a bandaid for a badly maintained system, needing this treatment, the nest would be alright. If you do not know what your old system is capable of, then it would seem normal to have to rely on these methods of heat management.

    If you have a balanced system, then the constant temperature would be best--NBC
  • Joe V_2
    Joe V_2 Member Posts: 234
    edited January 2013
    Not a customer; a relative.

    The house is well insulated and comfortable throughout.  Second floor apartment slightly warmer ( 1 degree)  throughout.  Boiler system is well maintained.  No issues.  He likes it cool during the night and noone is home during the day.  He is just saving money.



    And, he has a baby grand piano that doesnt mind the temperature swings. But that is probably not relevent.

    Other bennies include wifi that also monitors outside local temperature and remote control and monitoring via smart phone which is where photos are from.  I'm in NC and can raise or lower his house temp at will.  Plus, there is the obvious trending capability as seen in the photos.
  • ChrisJ
    ChrisJ Member Posts: 11,985
    pressure

    How many times does the burner kick off due to pressure during that 8 degree recovery?   Even my system will cycle on pressure at least once doing an 8 degree recovery on a 20F day.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Jamie Hall
    Jamie Hall Member Posts: 17,164
    Yike

    I beg to differ.  It is highly unlikely that your relative is saving money with that large a setback.  Running the boiler 3 to 4 hours, which I believe you mentioned, should be necessary only on a day very close to design temperature; on a "normal" day (today, for example) the boiler in the building I super may run as long as an hour and a half; it may not even run that long...

    On the baby grand.  All I can say (I should note here that part of my charge here is to see to the care and maintenance of three Steinway grands) is that I'm very happy for your piano technician; I'm sure he can use the money...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Joe V_2
    Joe V_2 Member Posts: 234
    Don't know

    Pressuretrol is set to 2psi and heat is delivered in 15 minutes.  I would say not too often but I dont know.
  • Joe V_2
    Joe V_2 Member Posts: 234
    edited January 2013
    nah, the piano does fine.

    No sour notes.

    He will wait and see his fuel bill soon.  The nest was a gift so time will tell.  But, to be fair, that is an operator issue.  It seems the nest is capable.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,512
    Remote access

    The Internet/smartphone capabilities are a plus for this, but that schedule of raising the temperature at 6 then lowering it at 8 seems counterproductive to me. If he would try a constant 67 degrees for a few days, he might be pleasantly surprised.

    There is more to heating comfort than mere air temperature with any radiator system. The radiators are not just raising the air temperature, but also that of the colder walls in the room. You could have the "cold 70degrees" phenomenon in a situation like this.

    Of course some people like the sound of the radiators hissing air as they wake up to remind then they should soon feel warm shortly. Feelings of warmth and coldness are very subjective, and heavily influenced by other factors besides the true air temperature.

    For myself, I keep the bedroom at 65, which is more exposed, resultI in the rest of the hous being 68.--NBC
  • Sil
    Sil Member Posts: 72
    Isnt the proof in the gas bill?

    Joe V: 

    Can you speak to what your gas usage has been before and after the nest?  Isnt that really the "proof in the pudding"?
  • Joe V_2
    Joe V_2 Member Posts: 234
    Sil, that

    is what we are waiting for.  He just received it for Christmas.

    As I said earlier, time will tell and we can't fault the Nest if the owner runs it the way he wants to.  He is comfortable and if his fuel bill is lower then he will be happy too.  I believe that is the way his Honeywell was programmed.
  • ChrisJ
    ChrisJ Member Posts: 11,985
    Yep

    My Honeywell VP 8110 was programmed for I think 62 at night then 72 or something wake then back to 62 then back to 72.



    Thats for forced hot air, and even then I wouldn't use it because its just too much in my opinion.  You are right, his schedule isn't the fault on the Nest, but its still wrong for a steam system either way.



    Now, how does the Nest do with overshooting after the recovery?  Also if it is about to do a setback, say at 10PM and it calls for heat at 9:58PM will it fire up the boiler just to shut it off 2 minutes later never even producing steam?

    I ask because these are the things I've wondered about the Nest.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,512
    fuel bills

    when i had a new boiler installed, and undid deferred maintenance, i had to wait until the meter was read at the end of winter to find out the fuel savings. luckily our gas company included the degree days for the month with an historical gas consumption printout for the past 2 years; although they did not take a reading every month.

    the new nestling will probably not see anything informative on just one bill.--nbc
  • PMJ
    PMJ Member Posts: 1,122
    Meter Readings

    The gas company converted our meter to electronic read about 2 years ago. Now all monthly readings are actual and since daily HDD data is easily available good monthly feedback is pretty easy. Reading your own meter it is possible to say something intelligent about yesterday's results if you wanted to.

    It would seem that given the large changes in actual demand on the heating system from day to day that fuel used/HDD is about the only way to reasonably compare efficiencies of two different calendar periods. 
    1926 1000EDR Mouat 2 pipe vapor system,1957 Bryant Boiler 463,000 BTU input, Natural vacuum operation with single solenoid vent, Custom PLC control
  • Joe V_2
    Joe V_2 Member Posts: 234
    ..

    Chris, Temperature overshoots are almost non existent if you compare the schedule to the actual temp/on/off photos.  In the beginning the overshoots were large but the device "learned" how the steam system responds.  I interpet the first photo as a call for heat just prior to set back but it is hard to tell if it is long enough to create steam or a waste of fuel.

    NBC, we have to start somewhere and Jan1 is where he started.  I believe Con Ed provides detailed fuel usage online.  He is the only person I know to have a nest on a steam system and willing to let us learn.   
  • Joe V_2
    Joe V_2 Member Posts: 234
    Update

    So, here is an update on the nest performance.  My relative agreed to raise the setback from 63 to 67 and left the "occupied" temp at 71.

    This was done on the evening of Friday, Jan 18.
  • Joe V_2
    Joe V_2 Member Posts: 234
    Unsegmented graph

    May add info
  • Mark N
    Mark N Member Posts: 1,090
    Graphs

    Joe



    The graphs that you are posting are quite interesting. How many different ways can you display the data? It looks like you can display when the boiler runs and also total daily run times. Very helpful to track fuel consumption. Can it also display actual on and off times?
  • Joe V_2
    Joe V_2 Member Posts: 234
    these are the only two graphs

    the first, is the solid bar that just tells total run time.



    tap on any day and get a segmented graph where each red segment is "on" time.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,512
    Burner run-time

    It looks like the system is firing up to one third of the time in total.

    I don't have an hour meter on my burner, but I think I am not firing such a large percentage of each day.

    If the graph is showing us the call for heat timing, then there must be some short-cycling going on-maybe on pressure. How is the venting on this system?--NBC
  • PMJ
    PMJ Member Posts: 1,122
    Total Run Time

    Pretty tough to compare this for two different structures isn't it? Different total demands (outside temps) and different heating system capacities sized for different temp zones maybe?
    1926 1000EDR Mouat 2 pipe vapor system,1957 Bryant Boiler 463,000 BTU input, Natural vacuum operation with single solenoid vent, Custom PLC control
  • Joe V_2
    Joe V_2 Member Posts: 234
    The graph is

    Showing a calls for heat.  It is a one pipe system and all radiator/ riser vents work well.  Heats fast and quietly.  Could very possibly trip on pressure which is set for 2psi.  Outside temps that week were in the teens.  As you can see, the nest is holding temp well and it appears that the boiler comes on at least once an hour throughout the day for about (hard to interpolate) 30 minutes which is more than enough time to deliver heat, but I do not think long enough to trip on pressure. 
  • Kjmass1
    Kjmass1 Member Posts: 212
    please explain

    what happened on the Monday. Throughout the previous days there were calls for heat 12+ times. On the monday it drastically dropped...was that because the outside temperature rose? Or has it adapted in some way?



    Any update since last January in any fuel savings? Santa may be leaving me a Nest this year.
  • Joe V_2
    Joe V_2 Member Posts: 234
    edited December 2013
    update

    you would have to google historical temps in NYC for those posts and use the date of the original posts which go back to early 2013, I think.



    My brother has taken some advice from this board regarding setbacks. He likes the ability to tell if the boiler is working correctly from work and adjusting the temps higher via cell phone if he is out of town and the temps drops. He likes that the nest now has smoke detectors that can communicate with him via phone if one detects smoke.

    He told me to date his average winter gas bill is $125.00/ month to heat 1800sqft. That includes his oven and hot water heater which is large enough for him and the four tennents who share the apt above him.



    It's all good. he loves it. It works as well as any thermostat but if you have issues with the nest, I saw in home depot recently that Honeywell now sells a tstat with comparable features at a comparable price
  • jpf321
    jpf321 Member Posts: 1,567
    Degreedays.net will

    Have the historic degree days..
    1-pipe Homeowner - Queens, NYC

    NEW: SlantFin Intrepid TR-30 + Tankless + Riello 40-F5 @ 0.85gph | OLD: Fitzgibbons 402 boiler + Beckett "SR" Oil Gun @ 1.75gph

    installed: 0-20oz/si gauge | vaporstat | hour-meter | gortons on all rads | 1pc G#2 + 1pc G#1 on each of 2 mains

    Connected EDR load: 371 sf venting load: 2.95cfm vent capacity: 4.62cfm
    my NEW system pics | my OLD system pics
This discussion has been closed.