The gas input is the approximated quantity of btus/hr that is going through the gas valve to be combusted. The heat of the flame and the flue gases is moved to the water flowing through the boiler. How well those btus/hr are moved provides us the output ranking. On this tag, the output ranking is difficult to comprehend due to the fact that the worth altered from btus/hr to “SQ. FT. H.W. RAD.”. What does that suggest?
Does it imply the square video footage of a home with warm water radiators? If it did, what would be the element? I typically rough price quote a boiler size from the square video of the heated area and the condition of the insulation. A lot of professionals will understand if the structure is loose, tight or someplace in between.
I generally utilize 50 btus per square foot of heated area for a really loose structure. A worst case situation would be the 1066 output times 50, which provides us just 53,300 btus/hr output from the 200,000 btus/hr input. Something isn’t right there. That score does not appear to associate with the square video of the heated area.
The 20% Rule
Gas-fired cast iron sectional boilers with climatic draft utilized what looks like the precise very same element to determine their output up until federal government policies obstructed. Nearly each I’ve seen from the ’50s and ’60s took 20% off the input to compute output. On this tag, considering that it is from that period, the output in btus/hr must be 160,000 btus/hr, or 20% less than 200,000 btus/hr.
It does not state that, so let’s attempt another analysis. Cast iron radiator areas have actually constantly been ranked by their maker. The ranking typically utilized is what we now call EDR, or Equivalent Direct Radiation. Because many cast iron radiators can be utilized for a steam system or a warm water system, the EDR ranking might then be utilized quickly to compute the output of a radiator based upon the steam pressure in the radiator or the water temperature level in the radiator.
What is inside the radiator identifies just how much heat it can produce. The exact same size radiator produces much less heat with 180 ° F water distributing through it than if the radiator was filled with low pressure steam. A 60 sq. ft. EDR radiator warmed with steam produces 240 btus/hr per sq. ft. EDR, or 60 times 240 equates to 14,400 btus/hr. The exact same radiator heated up with warm water at 180 ° F produces 150 btus/hr per sq. ft. EDR, or 60 times 150 equates to 9,000 htus/hr. That is rather a distinction.
If we now attempt increasing the 1066 revealed on the tag times the element for warm water at 180 ° F, which is 150, the item is 159,900 btus/hr. That is really near the 160,000 btus/hr I would have anticipated if the tag provided us the output in btus/hr. When once again, output is 20% less than input, or in combustion effectiveness terms,
