Boiler Water Temp?

rjbeery · Post by **rjbeery** » Sat. Oct. 10, 2009 9:59 pm

Just curious to see what temperature others are setting there boiler water temperature at? I've currently got my system set at 125 degrees and running 25lbs on the system.

What is the most efficient temp of hot water to pull heat off of it? Thanks

jim d · Post by **jim d** » Sat. Oct. 10, 2009 11:16 pm

the most efficient temp to heat with is the lowest temp you can use and still heat the dwelling thats why the older gravity type systems would heat the home in the spring &fall w/120 to 130* as it got golder outside the burner would run longer and the h2o temp would rise till the tt was satisfied ,as far as the pressure is concerned 25 is high ,releif goes off at 30# not that it will hurt any thing but ther isn't much of a cushion between the two

Post by **stoker-man** » Sun. Oct. 11, 2009 5:52 pm

13#, cold, is plenty for a two story house with the boiler in the basement. Copper baseboard radiators are rated at 180 degrees to work properly. I run mine at 140 in the early fall, but really need 160 or higher for them to heat the house when it's colder.

Robby · Post by **Robby** » Sun. Oct. 11, 2009 8:28 pm

I think those temperatures may be to low. I have been led to believe you must be 130F minimum to stop bacteria growth and prevent corrosion in boiler. On some wood fired boilers they install tempering valve to mix hot water with incoming cool water to protect boiler. I have no idea exactly why!
Why not ask the boiler manufacturer.

Sting · Post by **Sting** » Sun. Oct. 11, 2009 8:32 pm

because below 140 degrees

Flue gas will condense and bring corrosion and doom to your appliance

Post by **coaledsweat** » Sun. Oct. 11, 2009 9:47 pm

Also oxygen is driven out of the water at temps over 150*, that's the stuff that eats your boiler. I run mine @ 140-160* when I first start up, as it gets colder that will go up 20* or more if it gets bitter cold.

Tim · Post by **Tim** » Mon. Oct. 12, 2009 3:36 am

OK, been lurkin an watchin this post ..on My new AA NPO 130 oil unit Axeman states to keep the high limit set at 200..an the low round 160/170.
For the optimum heat transfer and DHW...with a mixing valve.
I do not have a mixing valve installed but feed our electric hot water heater directly from the boiler hot water coil.
OOOH by the way since installing this new AA NPO 130 and new water heater ..electric bill dropped from $148/ month (actual meter read)pryor to starting up the new AA and install of the new tank to $84 this month (actual meter read)

When I was runnin the AA 130 coal boiler I always ran it at 190 high side an 160 low ..with great heat from the outside temps of 30's to zero.
I SURELY MISS THE OL AA130 Anthratube humpin away in the basemnt ..floors are cooler an house is not near as comfy as the last 15 yrs!!!!
But the wife is content at night knowin that she doesnt have to worry bought (THAT FUNKY SOUND FROM DOWNSTAIRS)..that would bother her all night while im at work.
Tim