How Does a Boiler Save you Money

Discussion in 'Boiler Forum' started by Soapm, Dec 18, 2013.

  1. Soapm

    Soapm New Member

    Messages:
    50
    Location:
    Aurora, CO
    I was looking at our boiler today. It kept coming on every time the water temp dropped then it cuts off at about 180. The irony is, we had a fairly warm day today yet the boiler seems content to maintain the water temp. I don't understand why people say boilers are more economical than forced air??? They maintain the water temp even if no zone calls for heat vs forced air that only fires up when there is a demand.

    I think in most of our climates even in the dead of winter there would be warm days the minimal or no heating is required...
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    FWIW, most modern boilers do not maintain a steady temp like yours. In fact, depending on your system, there is probably an add-on controller that could make it much more efficient. You may need to keep it hot IF you have an in-boiler hot water coil instead of an indirect tank, or stand-alone heater. But, adding an indirect WH would allow that to be changed, too, and, probably give you more reliable hot water during baths or showers.
  3. Reach4

    Reach4 Active Member

    Messages:
    1,900
    Location:
    IL
    I don't remember hearing anybody anybody saying that, but I guess they do permit zones that could save fuel costs. The initial costs are more.. I think the hydronic systems are quieter both from the system and the fact that they don't have pass noise from room to room. They can maintain an even temperature better. It is a premium heating method.

    That said, some boiler systems are more efficient than others. Search for a term "outdoor reset" to find one of the features that your system could benefit from.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    The top of the line boilers and furnaces can both run in the mid-90% efficiency range, but you'll feel more comfortable with a properly setup hydronic system than you will with forced air. The equipment tends to cost more up front, but the actual costs to run can be nearly equivalent. But, then take into account most forced air systems aren't really well balanced and can cause outside air to be pulled into the house from leaky ducts, and unbalanced, or inadequate returns. Forced air does make a/c easier, but the ducts are usually only optimized for one mode, not both heating and cooling.

    My favorite is radiant, in-floor heating. No issues with placing furniture, very even and comfortable, often, you can run lower temperatures than convectors or forced air (flat panel radiators may give results closer to in-floor - you can do in-ceiling, too).
  5. Soapm

    Soapm New Member

    Messages:
    50
    Location:
    Aurora, CO
    I wasn't looking to upgrade or change but I guess every system has drawbacks and this is one I noticed for a boiler. Ours was installed in 83 so I wouldn't call it energy efficient but I did notice how it runs, runs, runs even when there is no demand for heat like on a nice day like today. I would look into a more modern controller but I don't know if it'd ever pay for itself???

    Our other draw back are these old White Rogers zone valves. The push in connectors get intermittent and the valve disc doesn't always fully seat. It would be nice to twist two wires together and know I have a connection and confidence that if I hear the valve open and close it did just that, opened or closed without the mystery of did that little disc seat or not. Those valves cost us a lot in service calls and are the blame for much of our heating mysteries (stuck valve, valve didn't fully close, valve not responding to thermostat, intermittent connection etc...). And did you see the price??? How did I luck out and get these darn things...???

    If I knew how to solder I would cut those valves out in a heart beat. It's no mystery to me why they're discontinued...
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    FWIW, over the last forty years...with the price of energy, most appliances are more efficient and often, more reliable.
  7. Dana

    Dana In the trades

    Messages:
    2,785
    Location:
    01609
    If yours is a gas-fired cast iron boiler it can be cold-started without damage, and need not be maintained at temp. It sounds like your controls are set up for a boiler with an embedded hot water heating coil for serving up domestic hot water, but if the boiler isn't your hot water heater, there is no need to operate it that way.

    It is also pretty rare to find a heating system so under-radiated that it EVER needs 180F water output. Even if it were perfectly balanced for design-day heat at 180F in 1983, most houses have seen upgrades in air-sealing & insulation, and possibly windows since then, which would allow you to drop the max temp, even once you sort out the control methods.

    A retrofit heat-purge boiler control such as a Beckett Heat Manager or Intellicon 3250 HW+ will always "park" the boiler at well below the max at the end of a call for heat, and always purge heat from the boiler until it hits the (programmed into the controller by you) low temp on a new call for heat before firing up the burner. This minimizes the average boiler temp during both standby and while operating, which improves it's efficiency considerably.

    Force hot air has two large operating cost down sides relative to boilers:

    1: Air handlers typically draw between 500-1000 watts, whereas circulating pumps are in the 75-125 watt range- easily measured in the power bill.

    2: Ducts are never perfectly balanced even when perfectly sealed, but they leak causing, air to go to/from unintended areas, both inside and outside the house. The room-to-room pressure differences created by the air handler (even with perfectly sealed & Manual-D balanced duct designs) drive air infiltration orders of magnitude higher than natural "stack effet" infiltration rates, and comparable to the house leakage rates under high wind conditions.

    The net result is ~10-15% higher fuel use for hot air furnaces at the same steady-state efficiency of a hydronic boiler, and 5-10x the power use.
  8. Soapm

    Soapm New Member

    Messages:
    50
    Location:
    Aurora, CO
    Wow Dana, thanks for the great response. I looked at that Intellicon 3250 HW+ and you got my gears churning. Looks like it measures the loss and switches the boiler to low duty mode when it really isn't being used (my layman understanding). For $173, I think it might pay for itself in say 5 or so years. That would be worth the investment.

    This is the boiler. It's in our church so we have the R-250. We do not use it for hot water though I would love to get rid of the hot water heater. I think it's an 80 gal tank that heats water all week long only to be used for a few hand washings on Sunday.

    When we do have programs at the Church, we never have enough hot water to prepare the food, feed then clean up. I would like to get a tankless but we can't afford the upfront cost. I believe the boiler would do a better job but I have no idea how to change the piping.

    I will look into that Intellicon 3250 HW+ controller...
    Last edited: Dec 21, 2013
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    A properly setup indirect WH should be able to provide nearly endless hot water for your functions. One way to make the WH provide more useful hot water is to boost the temperature add a tempering valve so it is safe at the point(s) of use. You could add a tempering valve to the existing WH, but it would be more efficient using the boiler, and have faster recovery.
  10. Soapm

    Soapm New Member

    Messages:
    50
    Location:
    Aurora, CO
    So in effect, the indirect WH becomes another zone on the boiler???

    We have a tankless in our home which didn't really save me money because now my daughter and wife take 45 minutes showers but I could see it saving money at the Church. Especially if we installed POU unites in the restrooms... But that initial cost is a bit much for our little Church.
    Last edited: Dec 21, 2013
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    Basically, yes, an indirect becomes an additional zone, and if providing max hot water is an issue, it becomes a priority zone so it gets the entire capacity of the boiler when it needs it. This rarely is noticed since the building has some much more thermal mass.

    A tankless can work, but the amount of water at any one time may be limited, especially in the winter when the incoming water can be quite frigid - they can only raise the water so much, and the more you ask of it, th eless rise you get, or the amount you get is diminished.
  12. Soapm

    Soapm New Member

    Messages:
    50
    Location:
    Aurora, CO
    We're talking about cooking and cleaning in a small church kitchen along with the use of two restrooms. It's no problem if we have to wait a little longer for the sink to fill ROFL...
  13. Soapm

    Soapm New Member

    Messages:
    50
    Location:
    Aurora, CO
    I bought and installed the Intellicon HW+ and it seems to be working as advertised. So here is my question, the design of the Intellicon is to ignore the low limit setting of the normal controller and instead have the boiler re-fire at the Intellicaon setting which is factory set to 145F. Mines is still at default.

    I've been reading that there could be a problem if the normal controller turns off the circulation pump prior to the 145F in that no heat is going to the zone until the water is reheated to the minimum to turn the circulating pump back on. This means the building can go through a period of time when it's demanding heat but none is being provided which then causes temp swings.

    Our controller is the Honnywell L8148E. How do I know if it has this problem? How do I know if it's turning off the circulating pump at say 160F so no heat is provided from the time the water drops below 160F to when it reheats up to 160F? I can't find any technical info in this area.

    Secondly, if my circulating pump runs anytime there is a demand from a zone regardless of the temp (which I think it does but I am not sure), then can I get additional savings by setting the low limit even lower? Like say 125F or lower? My understanding is that there are new boilers who's high temp is 140F and they work to heat as designed so logic says mines can also provide heat in the 145F (default low limit) to 125F (my new low limit) range. If that is so then I would get additional savings from the additional burner efficiency. Am I on the right track or am I in left field?
  14. Dana

    Dana In the trades

    Messages:
    2,785
    Location:
    01609
    If you have the system set up correctly, the pump should be running whenever there is a call for heat. If it is operated by a separate aquastat that cuts out at low temp, that aquastat needs to be adjusted down to a few degrees below the programmed low setpoint of the Intellicon, to guarantee that it always purges the boiler heat down a temp where it kicks the burner on when there is a call for heat.

    Since the boiler is natural gas you can safely program the low point of the Intellicon to about 130F, but if oil-fired it can be set it no lower than 140F, even if the flue has a stainless liner. Even though you won't get significant condensation on the heat exchanger plates by setting it 5F lower than that, the risk of flue condensation dripping back into the boiler rises. The default setting of 145F is safe for even the worst-case oil boilers hooked up to terra-cotta lined flues, and even most of those would be fine with a 140F low-temp.

    See page 6 of the manual regarding boiler-bypass and return water temps. The manufacturer recommends 140F as the low-limit for return water temps, which is fairly conservative, probably TOO conservative. With an atmospheric-drafted gas boiler like you can probably take it all the way down to 125F at your altitude. At sea level even with optimal mixtures it's hard to get much condensation at 125F boiler temps even with boilers designed to make use of that condensation. The lower atmospheric pressure at 5K' makes it harder still, just don't crank it down to 120F. But if you want to play it safe, set the low limit on the Intellicon for 130F, and time how long it takes to get back up to 140F, which SHOULD be pretty fast, several 10s of second. If there is bypass plumbing that can be tweaked to feed a bit more boiler output into the return water mix, set it up such that no later than 90 seconds into a burn the return water is above 130F. (It's fine if it takes longer than that on cold-starts.) If there is no bypass plumbing and the system is running 120F return water all or most of the duration of the burns, you'll have to start bumping up the low-limit.

    The lower you set the low limit, the lower the standby losses will be, and the shortest burn cycles will become longer, and more efficiently the system operates. But setting it up to always run at condensing temperatures WILL destroy this boiler in one heating season, since it isn't designed to tolerate condensation on the heat exchanger plates.
Similar Threads: Does Boiler
Forum Title Date
Boiler Forum Tankless Coil in oil fired Boiler doesnt produce hot water/ boiler doesn't turn on Jan 26, 2012
Boiler Forum Boiler doesn't turn on but zone valve opens Oct 23, 2010
Boiler Forum Circulator pump but boiler does not fire May 6, 2009
Boiler Forum Secondary loop doesn't heat! Dec 31, 2009
Boiler Forum Boiler Scale Problem Yesterday at 2:45 PM

Share This Page