Two Pipe Steam boiler overflow

Gurion

I own a nineteenth century row house in Brooklyn with a two pipe steam system.  I have been running the heating system ( a Burnham) for twelve years with really minimal intervention - emptying rusty water every few months and putting rust inhibitor in once every two years or so and flushing the system.  Over the last six months we have been renovating our house and have moved a few radiators and installed one new one.  Doing this has sent the system haywire and I believe the contractor (a plumber) really doesn't understand what to do about it. 



At first, the system clanged like crazy.  The upper floors stopped heating and there was a wooshing noise when the system was running.  The contractor replaced the backflow preventer (not sure what that really does in any case), rebuilt the cleanout (this now at the absolute bottom of the return) and replaced much of the last run of the return in the basement (probably necessary - I think it was clogged, perhaps from material that fell down the risers while the work was going on).



<strong>The current problem is that the boiler is overfilling itself on an almost daily basis.   </strong>I've emptied the boiler and filled it to the appropriate level.  When the system is running, I hear the autofill pump turn on three or four times during the time that the boiler is heating, but the water level does not appear to rise.  Then, at the end of the heating cycle (or perhaps after two or three cycles) the boiler is flooded.  I have drained it almost daily for the last week or two,  One time, when I went to drain the boiler, it  gurgled as air entered for almost half a minute before water started to come out (this is not the usual pattern but it did happen once).



I am not sure where the water is being retained before it is returned to the boiler.  Possibly of note, there are two pressure settings on the boiler. One, on the left, is set to 1 psi.  This one is right above the autofill. The other, on the right, is set to 7.5 psi.  I have not changed these, but it is entirely possible that the contractor has.





Any thoughts on this?  I am really at wits end and don't really want to let the contractor loose on this to replace one piece at a time (left to his own devices, he would convince me to replace the entire boiler, which is working perfectly well other than this annoyance).



You can email me here or at my personal email address <a href="mailto:danny@sarmag.net">danny@sarmag.net</a>



Thanks in advance,



Danny

crash2009

Contractor turned up pressure?

Could you post a photo of what is set to 7.5psi?

Gurion

Pictures of system

This is a picture of the boiler



This is the  higher pressure setting



And this is the lower pressure setting

Gurion

Two more pctures

This is the return assembly



and finally the backflow prevernter, which seems to me not to do anyting for the boiler since it is on the far side of the autofill mechanism (which is normally closed)

crash2009

Good, you have 2 pressure controls.

In pic 3, that looks like a PA404 pressuretrol, you said that one was set to 1.5psi.  1.5psi is ok at this point.  Does that 0-30psi pressure gauge work?



In pic 2, I can't tell what kind of pressure control that is.  Can you read the model # off that one?  You need to add a low pressure gauge.  0-3psi from gaugestore.com  If you adjust the settings on that one it will be difficult to know where you are set.  The indicators on those Honeywel boxes can't really be trusted.  For example you may be set to 7.5psi and the boiler is actually at 3psi.   

Gurion

Device model

It is a Pressuretrol L4079B1033 .  Looking at it closely it has a reset button on it - not that I have ever "reset" it in all the time I've run the system.



Thanks



Danny

Gurion

Pressure Guage

There is a gauge on the side of the boiler that reads pressure.  When the system is pressurized it  usually reads 10.  When the boiler is off, however, it does NOT reads 0.

crash2009

I just looked up the

L4079B1033.  That is a high limit, manual reset.  If your pressure ever gets to 7.5psi., that pressuretrol will shut down the boiler.  This is a good thing, leave it alone.

Gurion

So then

Now that I know what not to do (although as I noted, the gauge sometimes reads 10)  - any ideas why the thing is flooding?  Where could the extra water be hiding?  My assumption is that it is held in place either by pressure of vacuum, replenished by the autofill and then flows back to the boiler when the system cools.  What I can't figure is why this is happening now and what I can do to fix it?



Thanks -



Danny

crash2009

I am guessing

 that the PA404 is not working correctly, the pigtail is plugged, or the condensate return lines are partially plugged .  This is causing the boiler to steam all the water out of itself.  Then the water feeder fills the boiler up.  Then a few minutes later, the original water from the boiler finally gets back which causes you to have to drain it.

crash2009

Ask your plumber

 to remove the pigtail and clean it or replace it.  Add a low pressure gauge so you know what pressure you are at, then test the PA404 to see if it's working.  Then replace the PA404 if it doesn't work. 



You also mentioned that when the feeder is running, the sight glass water level does not change.  This suggests that the upper or lower is plugged.  Have him clean both of those as well. 

Gurion

Course of action

I've flushed the thing fairly regularly and the water seems to run fairly clean from both of the valves in the return lines  (although not so clean from the boiler itself).  What is the pigtail and how do I clean it.  How can I test if teh PA404 is working properly and what is the proper next course.  I am reluctant to jump on replacing the part, because all of this started when the GC started changing the layout of the system.

Gurion

Low pressure gauge

Is a low pressure gauge something other than the gauge next to the PA404?

crash2009

The pigtail

is labeled in the photo.  They are a pain in the neck to clean.  They are easier to replace.  If you decide to clean it.....

1-shut off power to boiler

2-remove wires to PA404

3-remove PA404

4-remove pigtail

5-ram a coat hanger through the pigtail to remove all the baked on crud

crash2009

Yes

The gauge beside the PA404 is a 0-30psi.  You must keep that for insurance and possibly building code reasons.  When I was speaking of the low pressure gauge, I was suggesting that you add one a 0-3psi available at gaugestore.com  Here are a few different ways to add it when you take the pigtail apart for cleaning.

Steamhead

That must be a pretty big rowhouse

to have a boiler that big.



Is this a Vapor system or the older 2-pipe, air-vent system? Post some pics of some radiators and also the vents at the ends of the mains so we can see it.



Vacuum can hold water up in the system, which would cause the boiler feed valve to open as the level drops and the water doesn't come back. But we need to know the specifics of your system, to know where to look for the problem.

Gurion

Pictures of radiators and vents

Thanks for replying I am attaching pictures of both of the vents - these are above the level of the boiler above the last elbow where the return(s) drop to the floor.  I've also included a picture of the boiler (standing back as far as I can without having the door block the shot) and of an newly installed radiator and an older installed radiator (this is the one with the white cup beneath it).



One other note, and I don't know if it makes any difference - I closed down both of the radiators on the garden (lowest) floor of the house because it was heating too quickly and shutting down the system before the rest of the house got heat.  One of the shut radiators still heats significantly - I believe it is being fed by the return pipe.

Gurion

Replaced the pressuretrol and the pigtai

Yes - it is a pretty big house.  It was built in the 1860s-70s for Irish/German merchants who lived here.  In downtown brooklyn only this row of houses and a few others in Brooklyn Heights were built to this size.    When I bought it 12 years ago it was a 5 family - now a 3.



I replaced the pressuretrol and the pigtail and added a 1-10 PSI gauge on a T off the pressuretrol.  The pressuretrol is set for 2 .  The boiler fires and build a pressure on the new gauge of about .5 (the older gauge reads 10 psi).  At that point the system shuts off and the autofill test light turns on.  The 1-10 psi gauge immediately drops back to 0.  Then the autofill adds some water to the boiler (about a 3-5 second burst) the boiler turns back on and the patterns starts again.  I won't be able to tell if the boiler floods until the house reached temperature and the boiler cools down.  I will let you know what happens.



One other thing that may be of note. I found the original air valve on the floor of the boiler room - it is  Flare No 59.  The GC replaced it with a Gorton No 1.  Don't know if it is correct or not.

crash2009

I am glad

 you have a working pressuretrol and gauge now.  Yesterday, we were driving down the troubleshooting highway, at night, with no headlights.  Was the pigtail plugged up?

During your "run test" today did you happen to notice what the sight glass was doing during the ON,OFF,AUTO-FILL,ON,OFF,AUTO-FILL

From your recent radiator photo's, (beautiful rads by the way) I notice you have been working on new floors.  The radiators are blocked up.  Is it possible that the elevation of the radiators has changed?  If so this may have changed the elevation of the pipes under the floor.  Maybe the pipes are not sloped anymore.  If so, this can cause condensate to stay up there and not return to the boiler.

Gorton is a good brand.  Don't throw away the Flare.  Thats an antique!

You lucky devil, your post has attracted one of, possibly, "the best", steam men in the country.  Frank "Steamhead" Wilsey 

 





 

 

moneypitfeeder

air vents

First thing I noticed (other than those are beautiful rads) is that you stated this is a 2 pipe system, and I see air vents on each of the rads pictured. Do you have traps of any kind on the return end of the rads? This question does nothing to solve the whooshing noise you hear, I would suspect a piping slope issue with the new/ moved rads,  but can also help to identify another problem you might have. I.e. clogged orifice, or failed return traps.

Gurion

Current state

The old pigtail was certainly plugged. 



The sight glass goes down during the on cycle.  



it rises (slightly) when the autofill runs



The house got very cold while the boiler was off so I haven't made it yet to the off part of the cycle.  The autofill has kicked in at least three times while the boiler was running, although my impression is that it has kicked in less. 



The GC installed some new heating lines, but swears that the pitch on each on was correct.  They are buried in the floor where I can't see them so I can't really tell..  I was curious about the difference in numbers between the Groton and the Flare.  My impression is that the old valve spent more of its time shut and less venting.



Finally, I've been  watching my newest toy, the pressure valve.  When the boiler is firing it is mostly around .5-1 although it has made it to 2  at least once that I saw it.  What is interesting (to me at least) is that when the boiler shuts off it falls to 0 over about half a minute and builds up slowly when the boiler turns back on.  The larger, older gauge on the boiler stays more or less at 10 psi irrespective of whether the boiler is firing.



Any ideas where to next?  I think the situation will be clearer when the system cools and I can see if it is flooded or not.



Thanks for your help -



Danny

Gurion

Steam traps

Thanks for the compliment on the radiators - we love them.  I had two of them powder coated recently.  I suspect that the baking may have scaled the inside of the radiators and sent cascades of rust/junk into the system.  I think I am through most of that.



I don't think there are steam traps on the returns.  The wooshing sound is gone, and I think was caused by corroded rusted out return that I replaced.  The water that is coming out of the spigot where the return meets the boiler.



What is disturbing is the following - if it were an issue of pitch, the water would accumulate somewhere. What seems to be happening in this case is that the boiler fills itself repeatedly while it is firing.  Then, as the system cools, the boiler floods.  It could be condensate or it could be water that is being held either by pressure of vacuum somewhere in the system and released later.



I am confused.

crash2009

Next

after seeing the condition of the pigtail you replaced, I'd probably get the boiler serviced.  Flush it out real good.  It probably hasn't been skimmed after the new pipes were added. I didn't see a skim port in any of your photo's.  When you add new pipes you add oil to the water.  Just a tablespoon of oil will screw your steam.  When you are wrenching on the pipes you loosen up a lot of crap that ends up in the boiler.  After we did mine, it took forever to get it clean.  I think I flushed and skimmed mine for 5 weekends in a row.  I got all kinds of crap out of there after re-piping.  chunks of teflon, bits of solder, rusted up bits of old pipe threads.  You may have other problems too, but I would eliminate the cleaning first. 

Clean the probe on the low water cutoff.  Clean the upper and lower sight-glass tapping.  Replace that other gauge.  Check the other pigtail.  Test both pressuretrols to make sure they shut off the boiler when they should.  Just give it a good going over on the water/steam side.  

Probably wouldn't hurt to get the combustion side checked later on.  The boiler was heating the place during the construction right?  Sawdust, drywall, sanding,

Gurion

Status

As the boiler cooled the water level rose to about 2/3-3/4 of the site tube.  This is less than it has over the last few days.  Moreover, it ran for a long time (because the house had cooled to the point that it was in the 50's).



One note of interest - the boiler's main pressure gauge (not the valve that I added today - the other one with the larger scale) read 10 PSI for most of the time that the boiler was firing - this even though the gauge that I added off the pressuretrol read no more than 2.    The water level rose dramatically when the pressure started to fall.  The level had risen when I went down and the gauge read something like 7 psi.



Why would the two gauges have such widely variant readings? 



Also - and this is just a thought - if the pressure really is 10 psi, assuming a 2" pipe there is roughly six inches area - would this be enough to push back 60 lbs of water and hold it in the riser?



Thanks -



Danny

crash2009

What is

 the model number of the pressuretrol you installed today.  The reason I am asking is maybe you can turn down the pressure a bit more.  When you had the plugged pigtail, the old pressuretrol was unable to do its job, your pressure was out of control.  Now you have it set to 2psi (32 ounces) and you can see an improvement. 

1-Can you imagine the improvement in the level of the water if you could limit your pressure to 8 ounces?

2-Are the radiators heating any differently?

Gurion

Lower pressure

I can try that - don't really know how the radiators upstairs behaved as I was down on the lower floor.  I'll check that tomorrow.



The one question I have is why the large gauge on the boiler still cranked itself to 10 PSI.  Why would the two pressures be different.  Also, while the new gauge did get to 2 it spent most of its tile while the boiler was firing at 1 and fell to 0a minute or so after the boiler shut off.  The other gauge stayed high.



Oh - the new pressuretrol is a clone of the original.  I replaced it with the identical part.



This is more art than science (IMHO).



Thanks for all your help, I really appreciate.

Steamhead

This is a two-pipe air-vent system

First of all- there should be no vents on the return lines in the basement. You do not want to let the air out of these returns since there's nothing to keep steam out of them, except for the air. This is probably why that garden level rad gets steam from the return line.



But you do need to vent the steam mains quickly. Measure the length and diameter of each steam main and we can tell you what you need.



Replace the Pressuretrol with a Vaporstat. The Honeywell part number is L408J1009. Running at less than a pound will, again, help keep steam out of the returns. With proper venting it will also keep your fuel bills down.



The original gauge on the boiler is shot. Replace it with a new one.



Then tell us how well it works!

Gurion

Maintenance

Thanks for the advice.  How do I identify a skim port?  I have flushed it a number of times and opened the cleanout.   I;ve also blown the water out through the spigot when the boiler is pressurized.  Is there a way to actually clean the inside directly or is it simply a matter of filling and draining.



How do I accesss the probe in the low water cut off?



I replaced the main pressuretrol yesterday.  Now that I am an "expert" (hah) I could also replace the other and its pigtail.



Danny

crash2009

Danny,

I suggested that you should "have that done"  Safety devices, such as the pressuretrol, low water shut off, etc., should only be worked on by licenced technicians. 

Skimming, and flushing the boiler, I think I can help you with.  What is the model of the boiler?