Boiler Temperature

Is 180 degrees the max for a residential dry base cast iron boiler. Would 190 degrees be too hot? Are there any pros and cons for a higher vs. lower temp.?
Thanks in advance
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Why?? Is it not keeping your house warm?
-- kjpro _-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>
( kjpro @ starband . net ) remove spaces to e-mail
Want it done yesterday? Or done right today, to save money tomorrow!!
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I'd like to know the proper temp settings.

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The proper settings are defined by the manual J that was completed on your house.

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180 is good unless on the cold days it wont heat or your pump runs continuosly, every place is different
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Mainly, you do not want to have a steam-boiler, for hopefully obvious safety reasons.
Pros: transfers heat more rapidly to building because of higher temp differential- higher recovery rate results. Cons: reduced efficiency because of higher stack temp, result of higher temp of "load" in boiler.
Ideally, for efficiency, temp would be set such that with lowest outdoor temps of year system can just hold t-stat set-point while pump(s) run constantly, _and_ burner firing rate is set low enough that burner runs constantly. This makes recovery difficult, though. :')
So you set the "aquastat" temp a bit higher than the optimum for efficiency, besides firing rate.
Other factors apply, certainly. Increased duty-cycle of pump(s) will reduce longevity. Reduced temp cycling of firesides and lower boiler temps will increase longevity there. Fuel's not free this year. You could put together a serious spreadsheet of guesstimates.
Of course, you have sealed and insulated the whole place well?
Regards, John
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Jon,
Thanks for such an in-depth answer. It was just what I was looking for.
I believe you're saying you want the boiler to be set as low as possible and still keep the house comfy. I guess 180 is a good setting for me.
Thanks again

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I have a 12 year old mid efficiency Viessman boiler in my 165 year old partially insulated stone house and I have had it running at between 100-120 degrees F. since it was installed, I even ran the old ineffiecent boiler at that temperature for over 15 years with no problem. My house is usually reasonably comfortable but I would be interested in knowing if I should run it hotter or leave it where it is.
I have had so many conflicting answers by so many so called boiler experts that I really don't know who to believe anymore.
Zack

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well Zak it sounds like its a bit OVERsized uh
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Mark:
I have been told exactly that so do you think I should leave things where there are or consider buying a smaller boiler that runs hotter but possibly more efficiently? Are there any safe ways to convert an oversized boiler to make it operate like a smaller boiler?
Any advise will be appreciated
Zack

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Oversized Air Conditioners are not good because they run too short a time to properly dehumidify the air. An oversized boiler will just heat the water, then shut off, then start when needed.
If you have the old big cast iron type or radiator, then a low temperature that is steady works just fine. No need for them to heat up to 180 degrees. You probably have a more even heat in the room with less fluctuation that other types. Ed
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Ed:
All my radiators are the old cast iron type.
Zack
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Old is good! I'd stick with the 100 degrees or so. They are not as responsive as baseboard, but they do a very good job, IMO. Ed
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Weil-McLain makes the Ultra boiler. It's been proven that the lower the temp, the higher the efficiency.
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Mark, if your answering Zacks question, I am interested in how you determine that the boiler is oversized because it is operating at a lower temperature?
The lower temperature boiler has nothing to do with it being oversized, the lower water temp requirement is because the radiation (baseboards or cast iron heaters ) in the living space are sized to put out the required BTU's of the room with a lower temperature.
An oversized boiler may be indicated if the boiler short cycled on high limit in a very short time while the home is comfortable. This would indicate that you have more BTU output from the boiler than what the radiation is capable of delivering in the same amount of time or the circulator is undersized if the water temp difference of the water leaving and returning is greater than 20 degree's.
Maybe I'm missing something of Zacks post...........
To Zack, the norm of boiler is to not have it lower than 140 or you can have condensation forming in the combustion chamber. This condensation can and will cause corrosion etc. But, 140 may not be obtainable without a bypass if your cast iron radiators are larger than needed.
Rich
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The boiler should be set to the lowest temperature that is high enough to keep your house warm.
An often overlooked, but significant, drawback to high boiler temps is the risk of scalding, particularly for children that haven't yet learned to walk. If you, or any frequent visitors to your home, have a crawling infant, keep that water temp as low as you can.
-- Regards, Doug Miller (alphageek-at-milmac-dot-com)
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I also have a thermostat that is set low during the day when there isn't anyone home. Is it better to set it low like 55 or more like 62? What would save more energy? The boiler woul dhave to work harder at 55 to get the house up to temp when it finally turns on to the comfy temp of 69.
Thanks
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