On my steam boiler the water level starts out about an inch above the low water cut off sensor probe, but as the boiler fires up and in the course of turning on and off during a 24 hour period, the water level rises to the top of the sight glass(no space left in sight glass). Which I am assuming is the top of the boiler. Is there any way to remedy this? The automatic water feeder is at the factory setting which is the longest delay time.
Also, if your water pressure from the city supply is high, should a reducing valve be necessary to install before the water feeder?

 

I'm no steamhead but as I recall there are several possible causes. One common cause is a slow leak thru the water feeder & the most common cause for that is rust getting under the valve seat. On the few steamers I service we've installed a simple filter ahead of & as close to the feed valve as possible & dramatically reduced the rust problems.
I don't think line pressure is usually a problem but I guess it could be.
Dan Holohan has some excellent books on steam heat.

 

If the boiler does not fire does the water level stay at the one inch level?

When the water level does reach the top of the glass are you draining the excess water?

A glass that slowly fills to the top when the boiler is producing steam is a classic sign of a plugged bottom connection. Are you SURE that the lower connection is clear?

And how high is your city water pressure? Anything less than 100 psi should be okay as long as the feeder valve does not have a slow leak as Grady mentioned.

How often do you "blow down" the boiler and what is the quality of your city water?

 

I haven't checked yet when the boiler does not fire if the water level rises. (But I will)

I am draining the excess water out.

When you mentioned a "plugged bottom connection" to check to see if it is clear... what is this bottom connection you are referring to? What is this bottom connection connected to and where would it be located. I have a Weil-McLain boiler series EGH.

I don't think the water pressure is that high.

I'm fairly new at steam boilers, when you say "blow down" the boiler, what does that mean? And how do you "blow down" a boiler?

The quality of the city water is pretty good.

Walter

 

When you mentioned a "plugged bottom connection" to check to see if it is clear... what is this bottom connection you are referring to? What is this bottom connection connected to and where would it be located.

The gauge glass is connected to the boiler proper with two angle fittings, one at the top of the glass and one at the bottom. These fittings may (or may not) have valves integral with the fittings. If the bottom fitting is plugged (or the valve is closed) the glass will fill to the top from steam condensing in the glass.

I'm fairly new at steam boilers, when you say "blow down" the boiler, what does that mean? And how do you "blow down" a boiler?

All steam boilers lose water when in operation. Because of this new water must be periodically added. This new water is called "make-up" water. Since the make-up contains varying amounts of minerals and dirt, these impurities are concentrated when steam is lost. These impurities will decrease the life of the boiler, sometimes dramatically. In order to keep these impurities to a safe level it is necessary to periodically drain, or "blow down", a portion of the water from the boiler.

Ideally your boiler has a drain valve located at the bottom and this drain is piped to a floor drain. If it is not piped to a floor drain then you will have to connect a short piece of hose to the drain and hold the free end in a bucket to blow down the boiler.

You want to blow down the boiler when it has NOT fired for some time. This is to allow the non-dissolved solids (dirt) to settle somewhat. Holding the hose in the bucket (if no floor drain) open the drain valve fully and let out between a quart and a gallon of water. If the water is really dirty you will want to let out more water but DO NOT completely drain the boiler. Let the automatic water feeder (if fitted) refill the boiler, or manually refill the boiler to the operating level and do another blow down the next day. Continue this daily until the water runs clear.

After you get the water to run clear this first time you may need to only blow down once a week or even once a month depending on how much water the system loses and how good the make-up water quality.


If you can post pictures of the boiler and the piping (more pictures are always better) one of us can point out other things for you to check. Pictures need to first be uploaded to a photo hosting site and then the URLs posted here.

 

Sorry, this may be a dumb question, but im trying to understand draining and adding water to the system

You mention that water add impurities to the boiler and thus reducing the longevity, then why would one continue to drain and add water?

So is it recommended to drain once a week or what is the recommened frequency of draining for a steam boiler during winter season?

Thanks

 

Your question is not at all dumb but is, in fact, a very important question and it is basic to understanding water chemistry.


All naturally occurring water contains dissolved and non-dissolved solids. The non-dissolved is what will settle out if the water is not moving and is commonly called dirt or silt. The dissolved is mostly minerals, chiefly calcium.

These solids do NOT evaporate and as the water evaporates, either naturally or by being changed to steam (by application of heat) the solids will concentrate in the remaining water. Adding more water, although it is bringing more solids to the original water, is also reducing the concentration of solids in what was remaining of the the original amount of water.

For example, (you can do this in reality or just visualize the experiment) take a glass of water and add a pinch of dirt. Stir it well and you will have a cloudy mess of dirty water. If you let the glass stand undisturbed the majority of the dirt will settle to the bottom of the glass. If you instead use a pitcher of dirty water and fill two glasses we can see what happens when the water evaporates.

Fill the two glasses with the dirty water you made in the pitcher. Cover one glass with a lid to prevent any evaporation and leave the other glass open to the atmosphere. Periodically agitate the two glasses to keep the dirt in suspension.

As the water in the open glass evaporates you will notice the water appearing dirtier. In reality there is no more dirt in the glass than when you started but the amount ow water is less so the amount of dirt in the water is greater per volume of remaining water. If you carry the experiment to the end you will have a covered glass with the the same amount of water and dirt as when you started and an uncovered glass with only the dirt you started with.

Now let's do the same experiment only this time we will add water from the pitcher to the open glass to hold a constant level of water. Do this until the pitcher is empty and then allow the water in the glass to totally evaporate. You will have a much greater amount of dirt in the glass and this additional dirt came from the water supplied during the experiment.

This is what happens in a steam boiler.

(more to follow)

 

However, if instead of just adding more slightly dirty water to the already really dirty water you instead poured off some of the really dirty water and added more of the slightly dirty water you would be making the water in the glass less dirty than it was before.

This is the concept of "blow down", adding MORE than the minimum amount of water, mixing it with the existing water and then removing some of the mixture back to the operating level of water. By doing this you can never achieve the lowest level of solids but you CAN minimize the increase of solids.


What you could not see in the above experiment was the increase in the dissolved solids which is also occurring but these dissolved solids are also controlled by the use of blow down.

High solids WILL cause problems in a steam boiler. These can range from water "carrying over" into the exiting steam to physical destruction of the boiler metal due to corrosion or "scaling" of minerals on the heating surfaces which will cause the metal to overheat and eventually fail.


The questions of how often and how much to blow down are hard to answer. In commercial and industrial steam boilers many tests and much instrumentation is used to determine optimal water chemistry. For residential steam boilers it is most common to use just the eye.

Blow down some water. If it looks muddy then increase both the amount and frequency until it is just a bit "dirtier" looking than the water feeding the boiler. Do this until you determine how often and how much is necessary. Short blows (a small amount) more frequently is better than letting it accumulate and then blowing a large quantity down the drain.

 

WOW. THANKS FOR the lesson FURD.
It makes sense to me now. Thanks for taking time out to write all that out and educating me.
I'm sure ill be back and will turn to you for more advice.
Thanks again!!

 

Furd - even though I did not participate in this thread, I just wanted to say that that was an amazing contribution to this forum. I learned a lot from it. Thank you!