1" copper system and BTU capacity

[Sawyer]

I was down in the boiler room looking at my existing LP boiler. I noticed that it is all 1" copper. Does that mean that the maximum output capacity of the system is 75K BTU? If so my heat loss calculations are off as this system will cook me out of the house at -30F.

Thanks, George

 

[LeonMSPT]

Depends on more than diameter of the copper, but generally 1 inch can handle up to 90K/hr... the longer the run, the less it will do. Might squeeze a bit more in a short run...

I was down in the boiler room looking at my existing LP boiler. I noticed that it is all 1" copper. Does that mean that the maximum output capacity of the system is 75K BTU? If so my heat loss calculations are off as this system will cook me out of the house at -30F.

Thanks, George

 

[Sawyer]

Thanks Leon, what you say makes sense. The runs are short, one 5' to in-floor, one 8' to a HX coil.

 

[joecool85]

My house is 1200 sq feet and I live in Maine, it isn't uncommon to wake up with 0F on the thermometer. According to many online calculators, I would need 100,000btu/hr to heat my house under those circumstances and that is with "better than average" insulation - which I don't have. My home has 67' of 3/4" baseboard, 6' of it is high output giving me a grand total of 42,000btu/hr that my house can consume. At 0F outside, my home can maintain 68F, when it gets below that I can't get the house above 65F. At this point my circ pumps never shut off. So obviously I need more btu/hr available (my furnace is fine as it puts out 120k btu).

Next summer we are planning on adding some baseboard to the living room and swapping out the 2' bathroom and 2' laundry room boards with high output. This will add 13k btu/hr to our system, bringing us to a grand total of 55,000 btu/hr - that should keep us plenty warm even in the coldest snaps.

My point is, btu calcs are frequently wrong. They over estimate what you need by about 2x to make sure you have enough no matter what, that your circ pumps aren't running like mad, and that you will be nice and comfy.

 

[Sawyer]

I am heating 4600 sq/ft, 2300’ up, 2300’ down, with 60’ of glass in the living room. The house is well insulated and sealed, triple pane glass. When I did the heat loss it came out to 90,932 BTU/hr…. Heating Degree Days = 9078 @ 70 degree F_90 degree differential.

 

[heaterman]

I was down in the boiler room looking at my existing LP boiler. I noticed that it is all 1" copper. Does that mean that the maximum output capacity of the system is 75K BTU? If so my heat loss calculations are off as this system will cook me out of the house at -30F.

Thanks, George

Probably not. What I would gather from those two factors is that your heating system is able to drop the supply/return temperature more than 20*. For example 8GPM @ a 30* drop means you are dumping 120,000 btu's somewhere.

 

[Sawyer]

I was down in the boiler room looking at my existing LP boiler. I noticed that it is all 1" copper. Does that mean that the maximum output capacity of the system is 75K BTU? If so my heat loss calculations are off as this system will cook me out of the house at -30F.

Thanks, George

Probably not. What I would gather from those two factors is that your heating system is able to drop the supply/return temperature more than 20*. For example 8GPM @ a 30* drop means you are dumping 120,000 btu's somewhere.

Thanks, I will have to go down with the infrared gun and check the drop. What you say makes sense.