Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Ways to set up indirect heater for the summer

Josh_17 Member Posts: 4
I have a 45 gal indirect connected to my oil/water boiler. In the winter the boiler maintains temp between 140-180 for both heat & dhw. With the summer approaching, and the thermostat off, what are the most effiecient ways to control the boiler so I am not burning more oil then necessary, while maintaing my dhw temp?


  • Derheatmeister
    Derheatmeister Member Posts: 1,514
    Electic Instant ??

    If you Breaker box supports the additional load you could Install a Electric Instantaneous Waterheater,or a external heat exchanger with a solar integration(that is if you have good exposure) or a combination of those..

    Just keep in mind that you Boiler is being Exercised now so if you do this you may turn your boiler on briefly in the summer to maintain the system. or install a "tekmar".

    Check Stiebel Eltron for the on demand water heaters..Heatmeister
  • J.C.A._3
    J.C.A._3 Member Posts: 2,981

    What do you have for a boiler control?

    I can honestly say that there are a few schools of thought on this. I believe that they all have merit...depending on the control.

    More info and we can point you in the right direction. Chris
  • Josh_17
    Josh_17 Member Posts: 4


    The boiler currently has what I believe to be the old version of a Honeywell L8124G. (do not know model # it is scratched off) It controls high and low limit. After recently installing the indirect I put in a Taco SR503 relay control with priority to DHW. It was recommended to me that I put in an outdoor reset, keep the low limit at 100 and only have the boiler start on a call for heat or dhw. What do you think?

  • J.C.A._3
    J.C.A._3 Member Posts: 2,981

    That sounds right to me. The only thing I would consider doing differently would be to put on a SR 503 EXP, and install the Taco 700 control. If you've got the EXP control, it's plug and play for outdoor reset and domestic hot water.

    The boiler has been warm since day 1 if you have the 8124, so I wouldn't change that. Maintaining some temperature holds merit here, and keeping the boiler at around 110° will give you a head start on making hot water a lot quicker than cold start. Chris
  • hot_rod
    hot_rod Member Posts: 21,793
    Check out George Lanthier article \"Updated Procedure\"

    in March Fuel Oil News He has an interesting view on cold vs hot-start boiler operation and indirect tanks.

    Maybe at www.fueloilnews or www.FiredragonEnt.com

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • bill_97
    bill_97 Member Posts: 172
    Josh , I have the same setup

    An 8124 with a Taco 3 zone with priority for a 30 gallon Phase 3 . I also have a Honeywell outdoor reset . I keep the low limit on the aquastat as low as it goes with the differential on the highest setpoint . We haven't run out of hot water yet in summer or winter . As far as fuel usage is concerned , dropping the boiler temperature until it's need is definiely a fuel saver . Like Chris said , add the outdoor reset for winter and you'll be amazed at what you can save . This is the first year I've tracked my useage down to the gallon and I'm very impressed .
  • mark schofield
    mark schofield Member Posts: 153
    lowest low limit setting

    I think that for the summer months when the boiler would cycle occasionally to maintain it's temperature, the most important setting would be the low limit which would keep the boiler at a temperature where condensation wouldn't become a problem. I have a similar application and keep the low at 130 deg, high at 180, differential at 25, and the OA Reset cycles the boiler when calling for heat. So far after 2 seasons no goo or sludge from moisture/condensation.
This discussion has been closed.