Floor Heat Boiler Efficiency

[Kirb]

From your experiences is it more efficient to run your boiler with flame on high with hotter temp that runs less or adjusted to a medium flame with lower temp that runs longer? I lowered mine to medium flame and it is keeping up with freezing but not sure if I'm saving gas.

Thanks,
Kirb

 

[Jim Caudill]

I'm no HVAC expert, but theoretically it's all about btu's, right? You need to input a certain amount of heat to acheive your goal (choose 250,000btu for example). You can do that by running a 500,000btu/hr boiler for 50% of the time or a 250,000btu/hr boiler continuously. Both situations should use the exact same quanity of fuel. However, there are some issues involving warm up and cool down; and if it didn't save some money, they wouldn't make staged boiler systems with modulating valves. So, just guessing, I'd say you are better off with a "throttled down flame" that only produces the btu's you actually need.

Similarly, they say to size an A/C so that it runs continuously at maximum load. I think that may have something to do with moisture removal though. Sporadic cycling of a boiler could produce excess condensation in the vent and allow for corrosion of the burner.

 

[JIMT]

Kirt,
The greater the temperature difference between the flame and the coils with water the greater the the efficiency of the heater, so a low flame will transfer a greater percent of its heat to the water. BUT, the flame produces water and if it condenses in the heater it will cause corrosion and the coil will plug and you will have very poor efficiency. So keep the flame up.
High efficiency furnaces work this way but are make of stainless steel and the condensation is pumped away.