How Many Btus

BigFoot · Post by **BigFoot** » Tue. Feb. 16, 2016 10:26 am

I have A AA130 and its heating my house (1800 SF) and my garage (1500SF) at -15 house was 62 + garage was 67+ , I set garage down to 55 and house when up to 69+ , Is my SF to much for the Boiler to keep up to make both 68+? using hot air to heat both (air handler in old oil burner and a modine air hander in the garage ,Was thinking of setting the water temp up from 165 to 180, to 170 to 185 ? will this give me more heat at both locs

Post by **Rob R.** » Tue. Feb. 16, 2016 10:49 am

The big question is: was your boiler hitting the high limit and cycling on and off? If it was, then raising the high limit will allow the air handlers to deliver more heat.

if the boiler was running nonstop, then it is a capacity issue.

davidmcbeth3 · Post by **davidmcbeth3** » Tue. Feb. 16, 2016 2:36 pm

As for the actual true BTU output max on your unit, that is an unknown.

But it hardly seems like a needed value when you already have the unit and have experience with what it can do.

165F seems on the low end of the ability of the system; raising it to 180F seems a logical step.

Post by **coaledsweat** » Tue. Feb. 16, 2016 3:53 pm

BigFoot wrote:Was thinking of setting the water temp up from the 165 to 180, to 170 to 185 ?

What are you saying here? The low is currently set to 165 and the high is 170?

Post by **Rob R.** » Tue. Feb. 16, 2016 4:05 pm

Axemans don't have a reputation for falling short of the mark.

coaledsweat wrote:
BigFoot wrote:Was thinking of setting the water temp up from the 165 to 180, to 170 to 185 ?
What are you saying here? The low is currently set to 165 and the high is 170?

That's how I read it. High limit should be at 180 minimum.

davidmcbeth3 · Post by **davidmcbeth3** » Tue. Feb. 16, 2016 5:21 pm

Rob R. wrote:
That's how I read it. High limit should be at 180 minimum.

Ya probably can go higher than that .... to about 200F I would guess ... but always double chk with the manufacturer

lsayre · Post by **lsayre** » Tue. Feb. 16, 2016 6:24 pm

davidmcbeth3 wrote:As for the actual true BTU output max on your unit, that is an unknown.

Not true. The AA-130 was designed by Penn State University scientists and engineers in a last ditch effort to stave off the inevitable post WWII rise in the use of oil and NG, and to stem the demise of coal burning. It is likely to be the most efficient coal boiler ever developed. In 1949 (ish) the government itself (the US Bureau of Mines, as I recall) did extensive testing on the AA-130 over a two or three year period in a real house. They found that it has an actual maximum input of about 115-116,000 BTUH, and it achieves 80-81% efficiency, meaning honest output is in the neighborhood of 93,000 BTUH. The entire exhaustive study is linked here on the forum somewhere. Yanche uncovered it and posted it. The AA-130 is likely the most researched coal boiler of all time.

blrman07 · Post by **blrman07** » Tue. Feb. 16, 2016 7:04 pm

lsayre wrote:
davidmcbeth3 wrote:As for the actual true BTU output max on your unit, that is an unknown.
Not true. The AA-130 was designed by Penn State University scientists and engineers in a last ditch effort to stave off the inevitable post WWII rise in the use of oil and NG, and to stem the demise of coal burning. It is likely to be the most efficient coal boiler ever developed. In 1949 (ish) the government itself (the US Bureau of Mines, as I recall) did extensive testing on the AA-130 over a two or three year period in a real house. They found that it has an actual maximum input of about 115-116,000 BTUH, and it achieves 80-81% efficiency, meaning honest output is in the neighborhood of 93,000 BTUH. The entire exhaustive study is linked here on the forum somewhere. Yanche uncovered it and posted it. The AA-130 is likely the most researched coal boiler of all time.

Found it!!!!

http://digital.library.unt.edu/ark:/67531/metadc38592/m2/1/high_res_d/metadc38592.pdf

lsayre · Post by **lsayre** » Tue. Feb. 16, 2016 7:11 pm

Excellent! Thanks Rev. Larry!!!

Post by **Rob R.** » Tue. Feb. 16, 2016 7:27 pm

davidmcbeth3 wrote:
Rob R. wrote:
That's how I read it. High limit should be at 180 minimum.
Ya probably can go higher than that .... to about 200F I would guess ... but always double chk with the manufacturer

Yes, I am aware of that. The boiler is rated to produce steam, but there is no point having the high limit higher than what is needed to support the heat load.

BigFoot · Post by **BigFoot** » Tue. Feb. 16, 2016 7:33 pm

Thanks for the help , I will be setting temp at 170 low and 185 high ,it would heat bout house and garage in the 70s at 20 and above , just at below that it starts to lose heat in the house not in the garage ,

Post by **Rob R.** » Tue. Feb. 16, 2016 7:48 pm

Generally you should keep at least a 20 degree spread between the low and high limit settings.

Do you have the zone relays connected to the TT or ZR terminal to signal a heat call?

BigFoot · Post by **BigFoot** » Tue. Feb. 16, 2016 8:44 pm

I have two separate thermostats that call independent with each its own circulating pump ,The garage zone 2 has 100ft of pipe to modine air handler , but seems to heat fine one 16x18 modine to heat a 24x32 two story garage ,down stairs 60 up stairs 68 all day ,house zone 1 has 6ft run to oil burner ,(air handler is 20x24 ) I had trouble with unburnt coal when I had the house only to heat ,when I added the garage I played with the water tem till I had it right , last year I heated the garage to 50 and 55 with no lost of heat to houst and it was cold last year , this year my boy lives up stairs and I heat 60 down stairs and 68 up with no heat lost to house till -15 happened then my heat lost started , now I set all to 60 and68 (garage) and 70+ (house) all is good ,till next cold snap so Ill try water temp at 170 low and 185 high first ,and as high as 195 to see if it will heat more !