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Tstat and boiler cycling for steam systems

BobbyC
BobbyC Member Posts: 96
I read on some threads the importance of cycling the boiler once every hour.  I don't do that now but if the advantages are fuel saving I'll be all for it.  can anyone share some insight on this and also recommend a tstat for my steam system.

Also, how long should the cycle last every hour?



Thanks

Comments

  • Rod
    Rod Posts: 2,067
    Thermosat Cycle Setting.

    Hi-  I'm presuming that your question has to do with the cycle setting on a typical  modern thermostat. 





    The cycles per hour setting only controls the number of times the stat can call for heating  inside a 60 minute time frame.  For steam - the setting is "One" cycle per hour.

    The idea of this is that it allows the heat from those high mass cast iron radiators to "coast" a while after the thermostat setting is satisfied as the radiators are still giving off heat. .  If you had thin tube radiators or fin base board, they don't have the mass of the cast  iron radiators and therefore wouldn't "coast" as far so you had this type, you might want to set the cycles to 2 per hour.  On a hot air system there is very little "coasting" so the cycle setting is usually 4 per hour.  Allowing the system to "coast" cuts down overall burner time and supposedly saves fuel.

    - Rod
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,564
    thermostat recommendations

    i have a honeywell visionpro for 7 apartments on 3 floors. i use the remote sensor option to sense the temperature in the most exposed unit [nw] i do not use setback as it would not save anything unless it were turned down for several days.

    i could have a tekmar 269/279 boiler control which would monitor the outdoor temperature, and run the boiler accordingly. it is more costly, and more importantly would require a learning curve of me, which i will probably embrace some day.

    the controls are only one part of the whole. the other factors which effect economy are:

    1.just enough steam pressure to be useful-2 ounces, controlled by a vaporstat,and verified by a low pressure gauge.

    2.massive main venting on the dry returns, with slow radiator vents [to start with].

    3.clean water in a properly-piped boiler.

    4.insulated steam pipes.--nbc
  • BobbyC
    BobbyC Member Posts: 96
    thanks guys

    I have cast iron rads.   I dont have a cycle setting on my tstat now.  When the tstat calls for heat it will fire up and the rads usually all get hot before the temp is satisfied and then it shuts down.  Most of the time it doesn't call for heat within the hour again.. 

    My best bet to keep it the way it is and just leave it around 1 temp all day and let the system do the work?  i ready it doesn't do any good for a steam system to drop the heat down when you leave the house.  Sometimes I'll drop it a few degrees when we leave with the thought of saving energy but seems like I"m better off keeping it at one temp. 
  • BobbyC
    BobbyC Member Posts: 96
    cycling question

    I have cast iron rads.   I dont have a cycle setting on my tstat now.  When the tstat calls for heat it will fire up and the rads usually all get hot before the temp is satisfied and then it shuts down.  Most of the time it doesn't call for heat within the hour again.. 

    My best bet to keep it the way it is and just leave it around 1 temp all day and let the system do the work?  i ready it doesn't do any good for a steam system to drop the heat down when you leave the house.  Sometimes I'll drop it a few degrees when we leave with the thought of saving energy but seems like I"m better off keeping it at one temp. 
This discussion has been closed.