Corrective action, HELP?

Michaelynn

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Steam

heating issues and observations the first week of January, 2010





Facts;





1.     

Poor heat distribution throughout.





2.     

All of the dry returns and underneath the column

rads are cold.





3.     

The boiler was changed by another contractor

last year & it appears they must have added a boiler feed pump.





4.     

Observed that the burner never shuts off and

positive (dry-steam) pressure is not achieved.





5.     

Observed that there is no steam in the dry

return to cause or hold back condensate.





6.     

We measured only 18” from the center of the

sight glass to the bottom of the primary boiler header. Do we need to redo the

header and increase it to at least 24”?





7.     

It appears that the original near boiler piping

contained some type of boiler return trap device that has since been removed.

It was above the water line with the bottom piped into the wet return with

check valves in the “gravity” wet return on either side (see pg. 266 fig. 56),

plus an auto vent just upstream in the common dry return drop.





8.     

We noticed that the current oil nozzle is

undersized by at least 1 gallon. Do we set this up to boiler manufactures spec?





9.     

The system is a three story residence built @?

We do not know exactly what heating system was originally installed. However,

we suspect that the original system was a two pipe gravity return vapor system.

The heating system components are comprised of two pipe steam, dry overhead

returns in the basement paralleling the mains, end of the mains dripped

directly into wet legs. There are cross-over trap-vents (Illinois

#2) from the end of the mains into the local dry return. There are two types of

radiation (column & cast iron) each having angle traps. The supply feeds

into the top of each. Some (@ ¾) have one-pipe steam vents installed which is

why they even are able to heat at all. High pressure to low…. We removed the

guts of one trap on a large column rad with no vent and the burner firing,

nothing!





10.  We just

installed three end- of- main F&T traps and nothing improved. Afterward, we

discovered at least two additional/original drips into a common wet return that

we assume must also require F&T’s to separate high to low. I suspect we

will also have to remove the guts of the old wet return check valves to enable

free flow back into the feed tank?





11.  Do we

eliminate cross-over trap/vents and plug and/or install end of main vents here?





12.  Do we

eliminate all rad vents and plug?





13.  What

is preventing the condensate from returning via the dry returns? Can it be that

presently the boiler is so under-fired that there is insufficient pressure to

overcome piping resistance?





Can

you specify the “FIX” for this job? Thank you, Michael Celiano, VP

(mceliano@ajceliano.com)





 

Jamie Hall

Sounds to me

as though you badly need a steam pro. to look at this system -- take a look at "Find a Professional" on this site, by state, and with luck you will find one nearby.  However, a few words...



First, do you have a copy of "The Lost Art of Steam Heating", by our host?  Also available on this site.  If you don't, get it.  You are going to need it, and it is well worth the investment.



Then... sort of point by point here.



The dry returns being cold is not necessarily bad.  They can be warm or cold, but should never be hot.  Be happy that steam isn't getting into them, though.



The near boiler piping should be checked against the manufacturer's installation instructions -- completely.  They don't issue these instructions for fun, and they describe a minimum set up for reliable operation.  Just for starters, it's unlikely that the 18" dimension from the sight glass to the header is enough.



The "device" mentioned under your item 8 may have been a rather critical part of the original system -- and may not have been a trap at all.  However, it's gone, so that's that.  It will be possible to work around it.



You mention a boiler feed pump.  This should not have been necessary either.  It may or may not have to go.  You also mention check valves in the wet return(s).  Ditto.



You imply that there are wet returns, in addition to the dry returns.  That was common.  Depending on pitch, the condensate might return to the boiler via the dry returns -- but it was more common for the dry returns to be pitched to the ends, and the condensate then went down to the wet returns and thence back to the boiler.  If the far ends of the wet returns are below the water line in the boiler, it will still do that.  If the ends of the wet returns are above the water line, there are ways to fix that without moving the boiler -- although the installer should have placed the water line where it belonged.



There should be no need for F&T traps on the drips to the wet return(s), if the wet returns are, as noted above, below the water line in the boiler.  They are (again) unnecessary.



Keep the cross over traps from the steam mains into the dry returns.  They were an essential part of the original venting scheme.  You mention an autovent near the boiler, where the dry returns drop to the wet returns.  This was probably the original main vent.  What size or model is it?  Chances are that it is too small -- but we need to know to comment.  If the cross over traps are working, that's probably the best place to have it.  However, you can put vents at the ends of the steam mains or the dry returns too.  It may be that a lack of venting is part of your problem.  If the cross over traps aren't working, fix them.



You do not need the vents on the radiators, assuming that their traps are working as they should be.



Now some more general thoughts.  It may well be that your boiler is either undersized, or badly underfired.  Either way, it will never, ever build pressure, as the system will condense steam just as fast as it is made.  It is not a matter of building enough pressure to overcome the pipe losses -- they are tiny.  This is a serious problem.  You will need to add up all the radiation in the building to determine what the rating of the boiler needs to be, adding a suitable "pick up" factor.  If the boiler is sized or fired less than that, you're out of luck until you get the size up to where it needs to be.



So.  Some things to do, while you look for a pro. and wait for your copy of the book.



First, are any steam mains uninsulated?  If so, get on it and get them insulated.



Second, check the pitch of all the mains and dry returns.  They should pitch consistently one way or the other, and my bet is towards the far ends.  At the lowest point, they must drip into the wet return(s).  If the pitch is inconsistent somewhere, check the pipe hangars etc. and get adjust so that it is consistent.



Check that the end of main crossover traps are functional; replace any that aren't.  Don't take them out!



If you want to leave the new F&T traps in the drips, fine.  Just make sure that you have enough head available above them to allow condensate to get through.  That would be a foot for the trap, and two feet for every pound of pressure that the boiler is set to cut off at, minimum.



Lose the check valves in the wet return(s).  They shouldn't be needed, and will only be a nuisance.



For the time being keep the boiler feed pump.  While it shouldn't be needed, it would be better to have a steam pro. look at it before getting rid of it.



Chances are the the ends of the wet returns away from the boiler may be dry.  Check the elevations very carefully against the boiler (or feed tank, if the feed tank is atmospheric).  If they are dry, there are ways to fix the problem -- but it will need to be fixed.



You might get a good oil burner man in to check that the nozzle in the burner is at least as big as the minimum recommended size for that boiler.  If it isn't, get him to fix that. 



While you are at it, make that list of all the radiation in the building, add it up, and compare it to the boiler rating.  You'll need the number eventually anyway.



What pressure are you trying to run at?  You won't need more than 1.5 psi, and probably less -- maybe considerably less.  Don't be tempted to crank up the pressure to try to get somewhere; it won't work.



I'll probably think of more, and I dare say that some of the other guys will come up with their own lists.