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Proper Fire Rate?

scrook_2 Member Posts: 610
the boiler? What brand & model number? What brand and model burner? What's the boiler manufacturer's recomended firiing rangerange? What and how big's the connected load (radiators)?

If oil or kerosene, the firing rate would be measured in gallons/hour. Gas would be measured in cubic feet/hour, coal (or other solid fuels -- say sawdust) would be measured in pounds/hour.

The steam output could be measured in BTU/hr or in square feet of equivalent direct radiation (EDR, where 240 Sq.ft. = 100,000 BTU/hr for 1 psi (215°F) steam), or even pounds/hour of steam (for process applications).

Why do you ask?


  • Tom_42
    Tom_42 Member Posts: 63
    Steam Boiler

    How much fuel should be used for firing the burner to make steam and can it be measured in Gallons per hour?
  • Tom_42
    Tom_42 Member Posts: 63

    if my burner could be overfired. I have an oil fired steam boiler. For the rest of the specifications you mention I will have to look them up. It is a pretty old boiler so some of the manufactuer specs might be hard to find. It is a Weil McLean. The other reason is that I know one of my radiator valves is bad as it is letting steam escape. I tried tightening it and it seemed to help. Then I took off the vent and all this steam came rushing out. All the radiators were hot at this point. And when that happened it made me wonder. I figure that that boiler shoudl shut off at that time via the pressuretrol. I am just learning though and probably have some of this all wrong.
  • scrook_2
    scrook_2 Member Posts: 610
    what's the pressuretrol...

    set at? Low I hope, less than 2 psi. If it's overfired for the *load* it'll reach pressure fast then short cycle on-off. If it's overfired for the *boiler* the flue gasses will be too hot. Is it (and the house) new to you? When was it last cleaned checked and tuned?

    If the t-stat's not satisfied yet you'd expect steam to come out if you take a radiator vent out. Sounds like a bad vent though, but boiling it in vineger *might* fix it if it's just crusted up w/ minerals.

    Look up the model number and series and the max firing rate in GPH on its nameplate.

    Figuring connected load is trickier, you need to look at radiator types, shapes, number of tubes/columns and number of sections, look'm up and add them up.

    How's the system run: even heat? quick to start steaming? quiet? sight glass clean? any other vents leak steam or spit water? Main vents (*big* vents at end of mains in cellar) vent air then close to steam? Insulation present on the mains?
  • Tom_42
    Tom_42 Member Posts: 63
    Just Serviced

    I just had it serviced due to lack of good steam. The tech vacumed out the boiler and increased the firing rate. The boiler I think is starting to short cycle. As for the pressure trol I believe it has a cut-in of 0.5 and a differential of 1 or 1.5. It's hard to tell on my system cause all it shows is the cut in value. It's an old honeywell pressuretrol. Anyway now the system does not take long to get up a head of steam.

    Yes other vents hiss. I just shut it down and there were several vents that were hissing as the steam was looking for a place to go.

    The pipes are all insulated in the basement. Not sure about behind the walls.

    I did a quick calculation and figured out the total EDR for all radiators is 79665 EDR.

    I checked the boiler and it is a tankless Weil Mclean rated ate 420 sq ft of steam. The temp is set to 180. The fire rate is rated to be 1.25 GPH. I think mine was just set to 1.5 GPH. Could this be a problem? Should I call back my service provider and have them lower it?
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