Cleaning a dirty main return

whitwo

My boiler water keeps getting dirty and I've been skimming it every few weeks. After skimming it looks good but after a couple weeks starts to get dirty again. After several long skims I decided to dig a little further. I took off the antler on one of my mains and put a scope down it and was pretty surprised at the level of gunk. I had some pipe leveling issues that got fixed a few months ago and am worried I might have part of a main slowly rusting out.

Anyway, I took these pictures. I ended up running some water through where the mains are and down through the wet return to a valve right before the Hartford loop. It was gunky at first but ended up clean. Are there other ways to clean the mains? Is that something I should do?

(Sorry for the orientation. The river of mud is really on the bottom)

JUGHNE

Are your wet returns above the floor or buried?

If you can drain the returns before they go into the boiler then you might keep the sludge out of the boiler, but perhaps consider replacing the wet return piping.

EBEBRATT-Ed

@whitwo

When you say mains are you talking about steam supply or wet returns? You shouldn't have any sludge in the steam side

Jamie Hall

I hope @whitwo is actually talking about wet returns... if so, the best thing to do is what he's already done: flush them out. There really isn't anything else one can do. Are they rusting out? Probably -- wet returns usually do, eventually. Are they leaking? If not, not to worry -- but pay attention.

whitwo

This is on the steam side.

Fred

whitwo said:

This is on the steam side.

That has to be in the wet return, below the boiler water level.

Jamie Hall

whitwo said:

This is on the steam side.

Up high? Carrying live steam? I have to believe you, since you say so -- but it's beyond unusual. Perhaps a picture or two of the piping, so we can maybe figure out how on earth that much and kind of sludge got into a steam main?

whitwo

Yeah, this is right where I took the main event out, just before it drops down to the wet return. That's why I was so surprised - I didn't expect sludge.

Hap_Hazzard

No one expects sludge. It's like the Spanish Inquisition.

clammy

Are your steam mains insulated ? Is your near boiler piping correct . Uninsulated steam mains in cold leaky basement will form more condensate forming more rust especially if the mains are under vented. I see this occasionally usually in systems who’s near boiler piping is crappola w no insulation w not proper main venting and old radiator vents which don’t function properly . Systems that are not vented properly tend to form carbonic acids and tend to form gunk in the main s badly pitch steam mains do not help by pooling condensate which is usually acidic from a poorly venting main . Usually on wet returns I install a ball valve on Hartford loop and tee w boiler drains on my wet return drops this way you can power flush ,I also add a tee to the boiler returns so it can be removed and the bottom of the boilers water side can be flushed out ,it’s not many who do this aside from those who post here unknow why most don’t I would guess lack of care lack of knowledge lack of money for job and most often the surety that they will never return to the job usually because of the first 2 and the 3 rd seals the systems fate. You should check and make sure your main vents are working properly meaning they vent air stop at steam and reopen to admit air when system is satisfied and done running . If your radiator vents are over 10 years old don’t be cheap replace them ,I know they cost but would you rather be uncomfortable w uneven heat and using more fuel ,short cycling and paying More to heat your home? How old is the boiler and has anyone ever cleaned the water side I often see this again in a boiler who’s water side has not been cleaned ever usually the wet return riser will look like that and when the return tee is opened the eq will be filled w goodness also the inlet return pipe of the boiler . If there 2 drains one he boiler I would flush and drain till all 5hat crap is gone . Peace and good luck clammy

Jamie Hall

In most situations, the presence of sludge indicates the presence of water; moving steam can neither carry not deposit sludge. Therefore... the next question is, why is there water in a steam main? How high is that main above the cold water level in the boiler? What pressure is the boiler normally running at? What is the cutoff pressure on the boiler, and does it ever reach that pressure? What is the condition of the drop and the wet return at that location and on back to the boiler?

ethicalpaul

Well there's always some water in the steam main during at least some parts of the heating cycle. This material is not like what I have seen in mine, though.

You said that you had some leveling issues. Was there a valley here? I could see rust flakes and mud collecting in a valley like this.

JUGHNE

The only rusted leaking steam mains I have encountered were a section of pipe with no slope or trapped water inside. They would rust thru on the bottom like you would expect a wet return pipe.
60 to 90 year old mains.

whitwo

I did have a section of main that was sagging and fixed a couple of months ago. I'm not sure how much those pipes were rusted. Mains are about 98 years old.

I also upgraded my main vents from some that barely vented to a pair of Gorton No. 1's on each main and fixed my near boiler piping. Maybe all this has led to flecks getting pushed down the line?

EBEBRATT-Ed

@whitwo
FWIW steam supply lines seldom rot. Not impossible but not as likely as wet returns

dopey27177

How to clean a wet return.

If you own a wet vac you can suck out a lot of the mud and sludge from the wet return piping and Hartford loop.

Refill the wet return again and vacuum all over again.

After it is done twice blow out the water with a water hose.

You still are not done. After a week or two you will need to remove the bottom plugs from the boiler or disconnect the piping from the bottom of the boiler and flush out the base of the boiler return passages.

Jake

Precaud

dopey27177 said:

You still are not done. After a week or two you will need to remove the bottom plugs from the boiler or disconnect the piping from the bottom of the boiler and flush out the base of the boiler return passages.

Thanks for this, I have been wondering about this very thing with my old boiler, which takes some time for added water, and especially returning condensate, to raise the level in the gauge glass to its resting level. After 60+ years, I anticipate removing the bottom plug to clean out the return passages will be a challenge...