Water doesn't get very hot in boiler

Water doesn't get very hot in boiler

PostBy: Wayne59 On: Fri Dec 11, 2009 9:28 pm

Hello,
I have been firing coal boilers for over 20 years, recently we replaced our old National 200 eight section cast iron boiler because it literally began falling apart. We replaced it with a National 300 Heat Extractor which is in better shape,this one has seven sections. I never had trouble firing a coal boiler before but even though I have a hot fire in this one I can't seem to get the water temp above 100 degrees. Everything is working right except that I noticed the base becomes so hot I can actually smell a hot metal odor sometimes. I think the heat that's supposed to give me hot water is being dissipated into the base. I wonder if there is supposed to be some kind of insulating gasket between the water sections and the base and if possibly the guys who put this thing together failed to install one, because I never had this happen on any of my other boilers. I used to be able to get good heat even with a small fire just burning on the middle grates in the old one and I never had the base get that hot. I am about ready to chuck this boiler because all I'm doing is burning coal without any benefit. Is it possible to insulate the base from the rest of the boiler? I know I'm talking about an old piece of equipment, but really 100 degrees, I need more heat than that.
Wayne59
 
Stove/Furnace Make: National Coal Boiler
Stove/Furnace Model: National 300 Heat Extractor

Re: Water doesn't get very hot in boiler

PostBy: LsFarm On: Fri Dec 11, 2009 10:27 pm

Did you clean out the water jackets inside?? A lot of mud and gunk can collect inside the sections and clog the nipples connecting the sections..

Greg L

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LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

Re: Water doesn't get very hot in boiler

PostBy: Sting On: Fri Dec 11, 2009 10:30 pm

What did the "wet side" of the vessel look like when you hooked it up? Was it all stoned up with mineral? Did you wash it out first/

Yes basic questions but we have to start someplace.

100 degree water -- measured by ??? just the gauge on the boiler -- how about your hand? 100 degrees is bath water -- 120 is hot enough to touch but you don't want to hang on long - hotter is well just hotter

at what temp is the supply vs the return pipes to the boiler -- is there a difference?

is the pump -- pumping??? Choke the flow -- a lot and see if the temp starts rise quickly. If it does your pumping at too hi a gpm -- if not check the pump again or open a wash out plug and check inside for mud. :roll:
Sting
 
Other Heating: BurnHAM=NG-gas


Re: Water doesn't get very hot in boiler

PostBy: Sting On: Fri Dec 11, 2009 10:31 pm

opps

Sorry Greg

You were faster. :oops:
Sting
 
Other Heating: BurnHAM=NG-gas

Re: Water doesn't get very hot in boiler

PostBy: Wayne59 On: Thu Jun 28, 2012 9:04 pm

Hello again,
It's been a while, but just want to let you know I found what the problem was. It was the way the flue was positioned by the guys that installed the furnace. Right as the flue came out of the furnace there were two 90 degree bends then it was a straight horizontal shot to the chimney. When I replaced the flue pipes I made the two 90 degree bends into one 45 degree and problem solved. Water heats up good and hot now. Funny how something like that could cause so much trouble.
Wayne59
 
Stove/Furnace Make: National Coal Boiler
Stove/Furnace Model: National 300 Heat Extractor