Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

23 KW electric boiler ...help

GtaGta Posts: 36Member
Hi, i have a 23 KW electric boiler, it is connected to a 3 zone radiant system. main floor 2000 sq ft / my bonus roon has 900 sq ft and finally the garage is aprox 1500 sq ft.

My hydro bills are crazy high, i think this lil 23 KW boiler is just maxed out. i was wondering would purchasing a bigger 28 kw boiler be more effient than the 23 that is running full out all the time? thanks sean

Comments

  • Jamie HallJamie Hall Posts: 10,469Member
    Probably not. If anything, they might go up if the extra capacity of the boiler allows you to run the place a little warmer. Running wide open all the time is the most efficient way an electric boiler can operate.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • JUGHNEJUGHNE Posts: 5,679Member
    Are you sure the boiler is running at the full 23 KW constantly?
    It should stage down as the return water temp rises.

    How is your insulation package?

    How many KWH per month, (not dollars) for the coldest.
  • GtaGta Posts: 36Member
    hi, aprox 7740 kw..... it shows all 4 led indicators are lit indicating all elements are running, the main zone has 11 runs /300 ft long each with each loop running at .5 gpm the temo on the boiler can barely reach 105-110 F this seems low to me as the aqua stat is set to 120f
  • ratioratio Posts: 2,010Member
    Is this a change from previous? Can you close off a few zones to see if the boiler can catch up? Post a few pics of the boiler & piping.

    If you're using all the heat this boiler can produce, a larger boiler won't be cheaper to operate.

  • GtaGta Posts: 36Member
    I was running all 3 circulation pumps in slow speed, i have now placed them all in high speed and adjusted the flow speeds on the manifolds accordingly......
  • GtaGta Posts: 36Member
  • ZmanZman Posts: 4,896Member
    What type of under slab and slab edge insulation do you have?
    How well do the spaces heat? Does it overshoot the target temp?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • GtaGta Posts: 36Member
    house is constructed on a crawl space , the main floor is just light weight concrete with the heat lines imbedded in it, the underside has the refltix " tinfoil" insulation between the floor joists.
    The bonus room above the garage has the same construction, but with rock sol insulation. the garage has really thick 10-12 inch white foam with a pink ridgid insulation foam on top. the house was constructed in 2011 up to code , i dont recall the name of the slab edge insulation but i know i paid for a frost barrier ..i assume its there.
  • GtaGta Posts: 36Member
    From above .... the farthest rooms are cooler , it does not overshoot the target temp, in fact tonite the t stat was set to 22 c and the floor temp was at 18 c
  • DZoroDZoro Posts: 761Member
    In between the floor joists on the main floor, is there just the foil or do you have R-19 below the foil?
  • GroundUpGroundUp Posts: 516Member
    Electric boilers are 100% efficient, and as has been stated, you wouldn't gain anything by going larger if the space is using all the BTU the boiler is making. When the supply is only able to reach 105-110, what are the return temps during this time? 7740 kw over a 30 day period averages out to 36,679 BTU per hour, every hour of every day which seems very excessive for 4400 sq ft of modern construction even at design. Does the home have a lot of windows? What are the outdoor air temps when the boiler can't keep up? Sounds to me like you're losing a lot of heat somewhere- whether through glass, through the slab edge, or more likely the tinfoil floor if there is nothing besides the Reflectix. Does the crawlspace get warm?
  • GtaGta Posts: 36Member
    Just the foil , nothing else . Yes the crawl space is warm . Could that much escape down? It’s actually very warm .. right now it’s 16c down there and there is no source of heat in the crawl space at all.

    What would be recommendations for insulation for keeping radiant heat up were it belongs?
  • GtaGta Posts: 36Member
    Oops the return temps are 72-74 ish at best I’m close to 20 f difference
  • GtaGta Posts: 36Member
    Yes lots of windows too ....😔😔😔😔
  • GroundUpGroundUp Posts: 516Member
    That Reflectix does nearly nothing to retain heat. Contrary to popular belief, heat does not rise. Hot AIR rises, which is not the case with radiant. You are pumping quite a bit of heat into the crawlspace that does not need to be there. I would stuff the joist bays with fiberglass batts if possible. The windows play a big role in heat loss also, but it sounds like your system is designed properly to run with a 20 degree delta. Tightening the envelope and retaining the BTU is the only way I see for you to lower the electric bill, starting with that crawlspace
  • GtaGta Posts: 36Member
    Really? Just plain old pink Fiberglas? Yes the flor joists are accessible... I guess it’s a cheaper try for sure , and a lot cheaper than replacing the boiler to start
  • GtaGta Posts: 36Member
    Would spray foam be a better thing than pink? I can just remove the foil, as this is s finished home I’m thinking the spray foam would get better coverage and be more air tight
  • Gary SmithGary Smith Posts: 271Member
    Do you have pipes in the crawl space that might freeze? If so you will have to provide some way to prevent (pipe insulation, and or heat tracing and pipe insulation.) But once you deal with preventing pipe freezing, leave the reflective foil if its tight to the floor and add thick fiberglass between joists. Inexpensive and easy relatively to tighten up the envelope.
  • BrewbeerBrewbeer Posts: 576Member
    Sometimes a conditioned crawlspace is better, the insulation is applied to the rim joist area, exterior walls and the floor of the crawlspace.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread: http://forum.heatinghelp.com/discussion/154385
    System Photo: https://us.v-cdn.net/5021738/uploads/FileUpload/79/451e1f19a1e5b345e0951fbe1ff6ca.jpg
  • Gary SmithGary Smith Posts: 271Member
    Yes that works too
  • GtaGta Posts: 36Member
    Yes all the home water lines etc are down there.... I doubt that freezing would be a problem. I like the idea of closed cell foam vrs pink.... cleaner and neater
  • ZmanZman Posts: 4,896Member
    Usually closed cell around the perimeter and pink in the bays is the most economical.
    Keep in mind that most closed cells do not have the flame spread rating required by code and need to have an intumescent spray applied if left exposed.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • GtaGta Posts: 36Member
    Yikes ... my main floor foot print is 2000 sq ft ...sigh this ain’t gonna be cheap esp in Canada
  • DZoroDZoro Posts: 761Member
    R-19 bat insulation will be the most economical and work well.
  • GtaGta Posts: 36Member
    Can u get that r value in rocksol? Pink is off the list
  • Jamie HallJamie Hall Posts: 10,469Member
    I don't find "Rocksol" insulation as such in my references, but I do find rock wool; perhaps "Rocksol" is a trade name for a rock wool insulation? In which case the R values are very close to the same as for fiberglass, of which "Pink" is the Owen-Corning trademark. The two are otherwise very similar -- including health hazards from fine fibers, if that's why "Pink" is off the list.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • GtaGta Posts: 36Member
    Yes , that’s a name that is sold here, and yes pink is off list for itchy reasons 🙂 I’m gonna get a spray quote before anything else .

    Question for all , I have the rehau digital t stat , in the settings there is a “ anticipator “ setting which is currently set at .2 amp

    If I increase this setting to say .3 would that have the boiler run a bit longer?

    I’m hoping that running 5-10 min longer would keep it off longer ... opinions? Thx
  • DZoroDZoro Posts: 761Member
    I personally like to see the temperature stay as tight to your set point as possible. You would be surprised how much lower water temp you can go to and still have plenty of heat.
    IMO
    D
  • GtaGta Posts: 36Member
    So should I set boiler max temp to say 30c or bout 90 f ?the max floor temp never goes higher than 27-28c anyway..... this is what the infloor sensor shows .
  • Jamie HallJamie Hall Posts: 10,469Member
    Gta said:

    Yes , that’s a name that is sold here, and yes pink is off list for itchy reasons 🙂 I’m gonna get a spray quote before anything else .



    Question for all , I have the rehau digital t stat , in the settings there is a “ anticipator “ setting which is currently set at .2 amp



    If I increase this setting to say .3 would that have the boiler run a bit longer?



    I’m hoping that running 5-10 min longer would keep it off longer ... opinions? Thx

    The various rock wool insulations available on this side of the border are also fibers -- and have the same itchiness problems. As noted earlier, spray foam is wonderful, but check your fire ratings; it may need to have a fireproof or at least resistant coating.

    Anticipators are a bit finicky, although they are superb when they are adjusted correctly. The best way to adjust them, though, is to try different settings to see what the effect is in your house with your system. And the best way to fiddle them is to start with a largish change, let it be for a day or two, then analyse better? worse? and edge closer to the best reading. Patience.

    Seems to me, though, that perhaps I'm a little confused here. In one place you have stated that the boiler is running flat out -- all elements on and can't get the water temperature up to where it's needed to heat the place. And yet just now state that you want it to run longer to keep it off longer.

    There's a contradiction there.

    Your best, least expensive, most efficient running will happen when the boiler is running at just enough power to keep the system water at the temperature needed to keep the building temperature where you want it -- with the boiler running at that power setting all the time and never ever shutting off, just bringing elements on and off as needed to maintain temperature.

    So... what's really happening?
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • GroundUpGroundUp Posts: 516Member
    "Roxul" is a type of mineral wool made by ROCKWOOL, same thing. Except mineral wool is a helluva bunch more itchy than fiberglass IMO. By the time you buy Roxul though, you could've mostly paid for closed cell already if code will allow. Fiberglass is cheap and easy as well as code compliant everywhere I've ever seen
  • CanuckerCanucker Posts: 532Member
    edited December 2018
    @Gta If you have the Roxul, use it. If you need to buy insulation, get the fiberglass. Both will get you 95+% of the sprayfoam performance at considerably less cost. They're both perfect for your application. Save the sprayfoam for insulating the crawl space walls.

    @GroundUp I've never had the pleasure of using mineral wool that was more itchy than fiberglass. It's all itchy if you don't dress for it. I prefer working with it compared to the pink stuff
    You can have it good, fast or cheap. Pick two
  • Larry WeingartenLarry Weingarten Posts: 1,499Member
    Hello, Blown in cellulose is another option. If you can find someone who knows how to properly do "dense pack", that would be my top choice. No itch, and little dust to inhale. B)

    Yours, Larry
Sign In or Register to comment.

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!