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when to fire it up?

at this time of the year, i am always wondering what range of low temperatures to start the boiler, so i am wondering what other building owners do.

 i could let ms. Honeywell decide, but i don't want everyone to boil when in this period the temps might be 40's at night, and 70's during the day.--nbc


  • Dave in QCADave in QCA Member Posts: 1,759
    Warm Weather Shut Down

    I use a Tekmar 279 to control my system.  I have the warm weather shutdown set at 55F for occupied mode and 50F for nite setback mode. This seems to be the temp when heat is no longer needed.  I have had 3 days this week that have dropped below 55F.  When morning warmup starts at 5:00 AM, the boiler has run.  Checking on the room sensor temps at 7:30 AM, I find them exactly at the set point of 73F.  By 10:00 AM, the system has gone back into Warm Weather Shutdown mode.  Temps have been stable throughout the day, no tenants have complained. 

    I find it a good time to check out the system and see what's going on.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • Jean-David BeyerJean-David Beyer Member Posts: 2,663
    I own my building.

    I leave my boiler on all year long because it makes domestic hot water too (Indirect hot water heater). It is cold-start with only 3 quarts of water in the heat exchanger.

    The control board will not allow heating to take place if outside temperature is over 70F (warm weather shut down; 70F is the default: I could change that if I saw a reason to do it), and no heating will take place even then unless a thermostat calls for heat. So far, for this heating season, there have been no calls for heat.

    My main heating zone is radiant in the floor with outdoor reset. The reset curve delivers 75F water to this zone (if requested) until the outdoor temperature gets down to 56F, at which point the curve slopes up until it hits 120F at 0F outside. And design day is 14F, so it probably never delivers such hot water.
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