Steam Boiler - 2 drains - one for Condensate Return?

nickc3

My Weill McLain steam boiler was installed with two drains.   I've always drained from just one of them - till water runs clear and then refill.



But, the other drain, I've never used.  It seems likes its "connected" to the Condensate Return piping.  Am I supposed to drain that as well???



Sorry for silly question.  Hopefully this is clear.

nickc3

Here's a picture

Here's a picture

Unknown

Wet Return Drain

The drain in the picture is on what is called "the Wet Return". Over time the lower parts of your system, like the bottom of the boiler and the Wet Return, collect any dirt (dirt, rust chips etc,)  that is in the system so it is a good idea to occasionally drain them both. Do this when the system is cold. After you have added new water to fill the boiler again, make sure you then turn on the boiler and heat the new water until the boiler makes steam as this drives off the dissolved oxygen in the "new" water. Dissolved oxygen is very corrosive and can quickly eat holes in your boiler dramatically shortening the boiler's life.

I would flush out your boiler/wet return a couple of times during the heating season and also at the end and beginning of the season. (Again- Always remember to bring the water to a boiler after adding new water).

 If you don't have one  yet I would suggest you might want to get a copy of Dan's excellent book  "We Got Steam Heat" as it will answer most questions you have and answer those that you haven't thought about yet!

- Rod

 http://www.heatinghelp.com/products/Books/5/61/We-Got-Steam-Heat-A-Homeowners-Guide-to-Peaceful-Coexistence

nickc3

How much of wet return do I drain?

How much do I drain from Wet Return?



From the boiler drain, I drain till it runs clear.  how about here?

Unknown

Drain

I'd drain it completely as there isn't much water in your wet return. Since your "new" water line is plumbed into your wet return, after the wet return  has drained you might give it a shot or two of fresh water and see if that washes out more mud. Then just close the drains and fill the boiler back to the operating level on the glass sight tube and fire the boiler up to remove the dissolved oxygen.

- Rod

nickc3

And, I assume do this when boiler is cooled down?

And, I assume I shoudl do this when boiler is cooled down, or fairly cool.



Thanks so much for your answers.  I only drained the wet return 2-3 times since I got this boiler 5 years ago.  Hope I didn't do any damage...I'm sure its not good that I didn't drain the wet return.

Unknown

Cold Boiler

Yes , let it cool way down first. Sorry, I probably should have mentioned that and also NEVER add water to a hot boiler!  To do so could result in an violent explosion! It also has the potential to crack the castings even if it doesn't explode.

If you notice on your system, the "new" water goes into the wet return which it allows it to mix with the warm boiler water a bit before it enters the boiler. If the boiler is empty and then you refill it, there is no warm water to mix with so it is important in this case for the boiler to be cold.

- Rod

nickc3

Cooling down - water feeder doesn't care!

Funny you mention not re-filling a hot boiler.   3-4 times since I got this boiler - it has Auto-Refill - and while it was running or right after a cycle, the auto-refill kicked on.  It happened just last night - first time in awhile, and my heart just sank thinking it will cause thermal shock.  Ugh.   What can I do about that, if anything?  I try to stay on top of things and make sure that water is a high enough level. However, in the dead of winter when the boiler is running most of day/night, I rarely get a chance to refill - and ironically, its thoes times when the dreaded auto-water feeder fills up a hot boiler.  I was thinking of just shutting the water supply to it since I'm very good about checking the water.



THanks again - your reponses are great and very much apprecated.

nickc3

Cooling down - water feeder doesn't care!

Funny you mention not re-filling a hot boiler.   3-4 times since I got this boiler - it has Auto-Refill - and while it was running or right after a cycle, the auto-refill kicked on.  It happened just last night - first time in awhile, and my heart just sank thinking it will cause thermal shock.  Ugh.   What can I do about that, if anything?  I try to stay on top of things and make sure that water is a high enough level. However, in the dead of winter when the boiler is running most of day/night, I rarely get a chance to refill - and ironically, its thoes times when the dreaded auto-water feeder fills up a hot boiler.  I was thinking of just shutting the water supply to it since I'm very good about checking the water.



THanks again - your reponses are great and very much apprecated.

Unknown

Automatic Water Feeder

Your automatic water feeder is fine. First of all the boiler isn't completely empty when the water feeder comes on.  The water feeder, if it is setup properly, just adds a little bit of water so the crown plate isn't exposed . In the case of your system, your new water enters the system on the wet return and it has to move quite a way before it is even enters the boiler. As it is  moving it is being mixed with hot boiler water and hot return water so that by the time it enters the boiler it will be the same temperature as all the other boiler water.

What you wouldn't want to do is completely drain the water out of a hot boiler and then immediately fill it with cold water. That could cause you a problem with thermal shock.

- Rod

nickc3

That makes me feel so much better

That makes me feel so much better.   I didn't realize the water gets mixed as it comes in...I'll have to go downstairs later and just review the piping.   

Hopefully it is as you state.  The installer cerainly made some errors that I've realized now - like using copper pipping.   Black pipe still runs to the radiators, but the new piping around the boiler is all copper.   Additionally, and perhaps as a result of this, I get water hammer upon initial start up that I never got with my 40 year old AMerican Standard.  I had some other plumber here the otehr day for other work and he suspects its because one of the mains is not pitched forward???  I thought all lines had to pitch back to the boiler.  He said, the condensate lines - yes, but not the mains going out.    I just think when the installer put the boiler in, he setup the boiler slightly too high, so the pitch got slightly off.  So, I have to deal with about 6-7 minutes of water hammer everytime.

Unknown

Terminology

When boiler are replaced all sorts of "weird" things happen. If you could post some more pictures of your boiler and piping above the boiler maybe we can determine what the problems are. Take the pictures from different angles so we will be able to trace out the piping. They don't have to be up close as we can blow them up if we need to look at the detail.



I took the picture you provided and labeled it which I thought might be of help as some of the terminology gets confusing.

Notes:

Red Arrows = Very Hot Water (Boiler water)

Pink Arrows = Very Warm Water (Returning Condensate)

Blue Arrows =  Cold Water ("New" make up water)

"A" + "B" are return pipes and return condensate to the boiler. They are called "Dry Returns when they are above the boiler's waterline and "Wet Returns" when they are below the boiler's waterline even though you can see they are the same pipe. Below the water line, the wet return piping is filled with water (condensate)

As you can see the cold fresh water entering has plenty of time to mix with the hotter water entering the Boiler Return Port.



The 2 return lines "A" and "B" indicate that you are likely to have two steam mains.

Is you system a one pipe or two pipe system?  This is determined by whether you have one or two pipes connected to your radiators. One pipe = a one pipe system etc.

I mentioned the "We Got Steam Heat" book earlier and I'd highly recommend getting it as it really helps you understand your steam system.

- Rod

nickc3

Pictures

Here are pictures...

Yes, its a ONE pipe system.

And, I will definetly be ordering that book.



Hopefully examination of my pictures doesn't reveal a horrible install.   I know the copper pipes were a mistake....not happy about that.

Unknown

Piping & Insulation

Hi - I looked over your pictures and generally the piping while not ideal, seems passable which means I'd just live with it. If the copper piping becomes a problem sometime down the line you can just repipe it then as I imagine you are past the point where you could get the original installer to redo it.

I've attached two of your pictures on which I have drawn in a modification. This is where have the steam books is a big help as I could then refer you to a page number as Dan explains things far better than I could.  From what i can see you have 3 steam lines coming off your boiler. Two of them look like parallel flow mains that is both the steam and condensate flow in the same direction away from the boiler and the condensate returns to the boiler by way of a dry return pipe, In the picture you can only see one of these mains and I marked it "Parallel Flow"   You might wnat to check that both these steam mains do in fact slope away from the boiler.



I think what your plumber is referring to is the main that I marked "Counterflow". From the picture I can't tell if it's actually a steam main or a radiaor lateral but it is definitely counterflow as it is sloped towards the boiler and the condensate (water) drains back into the steam stream coming up from the boiler. I drew in a "fix" for this which is a drip line that would divert the condensate back to the boiler by way of the wet return.



Before you consider doing any piping I'd insulate your riser and header coming out of the boiler. Being made of copper they have a higher heat transfer rate than black iron. What you have here is essentially a huge radiator which will condense steam and produce a lot of condensate especially during startup when the piping is cold. Insulateing it might cure your waterhammer on startup so this is what I would definitely try first. Use 1 inch think pipe insulation as that gives you the best "bang for the buck" Here's a good article by Dan on the importance of insulating steam pipes.

- Rod

http://www.heatinghelp.com/article/11/Hot-Tech-Tips/300/Why-you-should-insulate-steam-pipes