Coal Boiler Pressure Question

lsayre · Post by **lsayre** » Sat. Sep. 14, 2013 10:16 am

I bumped up my pressure recently, and today I'm seeing 16 lbs. at 205 degrees. Is that OK, or should I drop it down a bit?

Edited to correct my poor spelling.

blrman07 · Post by **blrman07** » Sat. Sep. 14, 2013 10:23 am

It's supposed to be at or around 12 but your OK. If it was me, I would drop it to 12-13 but that's just me.

Rev. Larry

lsayre · Post by **lsayre** » Sat. Sep. 14, 2013 10:30 am

To drop it, will I need to bleed it a bit?

Post by **Rob R.** » Sat. Sep. 14, 2013 10:47 am

15-16 psi is fine, so is 20...but your expansion tank should match the cold-fill pressure.

lsayre · Post by **lsayre** » Sat. Sep. 14, 2013 12:29 pm

Rob R. wrote:15-16 psi is fine, so is 20...but your expansion tank should match the cold-fill pressure.

No way at this juncture (that I know of) to tell what the cold fill pressure is. Will be shutting down and cleaning out sometime in early October, so I can check it then.

Post by **franco b** » Sat. Sep. 14, 2013 2:11 pm

Pressure as I understand it is only to raise the water to the highest radiator or heat exchanger. Three story house needs more than two story house.

Freddy · Post by **Freddy** » Sun. Sep. 15, 2013 6:57 am

As long as it stays below the blow off point of the pressure relief valve it's fine. Most are 30PSI. But, yes, the ideal would be as low as possible and still do the job.... 12 for a one or two story house, around 17 I think for a three story house. Generally.... 5 pounds for every 10 feet up.

gaw · Post by **gaw** » Sun. Sep. 15, 2013 7:30 am

If you are worried over 16 psi you don’t have enough to worry about.

Like the others said, it is a couple pounds higher than “normal” but it ain’t broke so I would not fix it.

whistlenut · Post by **whistlenut** » Sun. Sep. 15, 2013 12:05 pm

Larry, what size pressure tank do you have on that system? Your 16 lb question is not anything I would worry about......above 20, start looking for a reason.......or if it creeps up.

lsayre · Post by **lsayre** » Sun. Sep. 15, 2013 12:10 pm

whistlenut wrote:Larry, what size pressure tank do you have on that system? Your 16 lb question is not anything I would worry about......above 20, start looking for a reason.......or if it creeps up.

I have a #90 on it.

Post by **Rob R.** » Sun. Sep. 15, 2013 12:32 pm

You did your homework, that is a great tank to have on a coal-fired system. Every single expansion tank I have purchased has come through with about 8 psi. As you know, this is too low for a typical system that uses a static fill pressure of 12 psi. If the tank pressure isn't adjusted to match, you will have used part of the tank's expansion capacity before the water even gets heated.