Gas Steam Boiler (Has To Be Drained Twice A Month?

[crazyoildude]

I had a tank leak on a 20 year old slant fin Gas Fired steam boiler and i was told it would have probably been ok if i drained it and refilled it twice a month. (i did it twice a year during use)

What happens to the water inside that it should be drained so often?

I decided on a weil mcclean is that a good gas steam boiler for my house? It seems everyone has a different favorite. I don't know who makes good boilers these days. My old one is a slsnt fin. If i posted questions about a boiler before please excuse me but i could not find it if i did.

 

[Wolf359]

Sounds a little nutty. I don't think you're supposed to drain out all the water twice a month, I think that would make it rust out more. Usually I just blow it down once or twice a month if using a mechanical low water cutoff like a Mcdonnell-Miller 67 or 47. With an electronic probe, I don't do it as often.

 

[JHZR2]

My parents have a large 1920s home with two steam boilers. They are modern, though there was a an old coal boiler with a gas insert in there for one of them when I was real little.

I recall hearing exactly that one time when some service techs were in. They said to routinely remove a bucket of water or enough to get so my clean water flowing, and then refill. Filling is easy via the sight glass.

I remember doing it from time to time when I was young. The water that would come out at first would be black. Cast iron radiators and cast iron pipes do that...

That said, I have hydronic, and have read that one should not service the water, as you want to minimize the dissolved oxygen - let it react out and then the system, closed and sealed, will be inert.

Steam radiators do "breathe" so I suppose that is the issue. Oxygen is present, so scale can build and junk gets in the water... So keeping it clean keeps sludge and scale from building up in the boiler.

That said, does it cause the system to corrode faster?

 

[Shannow]

If you are producing steam, the salts and solids that come in with the water are concentrated in the water that's left behind after the steam goes to where it's going...the machines need to be "blown down" to remove the excess salts and debris.

Otherwise they concentrate, and either corrode stuff, or cause water side deposits that overheat metals on the fireside.

 

[JHZR2]

Originally Posted By: Shannow
If you are producing steam, the salts and solids that come in with the water are concentrated in the water that's left behind after the steam goes to where it's going...the machines need to be "blown down" to remove the excess salts and debris.

Otherwise they concentrate, and either corrode stuff, or cause water side deposits that overheat metals on the fireside.


Youre producing steam, but the purpose of the system is to condense inside the radiator and return. Typically a one pipe system, but losses are minimal if set up right.

 

[Shannow]

Have read about them ... never played with one.

One pipe would imply no path for non condensibles, which will create a "waterline" somewhere in the system, plus more area for corrosion...the products of which are returned to the boiler.

Just a guess.

But even power stations, filled with de-ionised water, oxygen scavenging, pH control and with condensate polishing and all steam side water returned to the condensate pumps still need to be blown down from time to time.

 

[supton]

Co-worker has one of those one-pipe setups; very interesting setup. I should ask him how it's doing now (he had lots of fun trying to get it balanced and working properly); I wonder if he knows about this need to let water out--he did lots of reading, as no one seems to know how to deal with it.

 

[IndyIan]

I'd start here. http://www.heatinghelp.com/forum-category/93/Strictly-Steam
Dan Holohan also has written some books as well. I bought one on the basics of hydronic heat.