boiler room flooded

helpJohn

hi all,



situation:



two pipe system on two basement rooms;  rest of facility has one pipe.   don't know why it was designed this way.



a twelve foot radiator on a 2 pipe system had major water hammer and leaking at vent and steam was coming out of the nipples on the return side plumbing.



numerous attempts by professional to repair failed.  someone had actually installed a ball valve at the exit.  there is a Hoffman 8C trap at the exit  - also a 1/2" trap at the supply side on a drip leg which connects to the return.



i removed the valve and installed a new trap at the return and replaced the supply side trap too.  nipples were rusted which explains the steam leaking - except steam should not be in the return.  called for heat at the stat but the radiator did not heat.  i deduced that the traps had failed in the open position and that was how the radiator heated.  to make a long story shorter,  I found a valve in the enclosed soffit which had been shut off all this time.  removed that and installed a rad valve at the supply.  radiator heats wonderfully now. 



but...



-after making this repair the boiler now cycles on and off between cut-in and cut-off pressures every 12 minutes and struggles to reach thermostat temperature setting. 



-boiler room flooded this morning - boiler still runs and does not look like it has flooded.  flooding could be due to



                                 (a)  heat was turned down to 50 degrees for a week and then

                                        fired up last night to 67.  cold pipes ( uninsulated ) may

                                        have produced excess condensate



                                 (b)  my repair altered the flow physics and now radiators can

                                       dump their condensate instead of filling up.



More notes;



                                (a) mains not vented.  having trouble getting my service company

                                      to realize the value of this.



                                (b) numerous steam traps in building which i thought were for two

                                      pipe systems ( with exception of large traps in boiler room ).     



                                (c)  Macon adjustable thermostatic valves were installed at the supplies of  one pipe radiators.   service company refuses to admit these are the wrong valves.  they should have used Macon opsk valves or some other.



sorry for the long post.  learning much about steam heat but once one mystery is solved it seems like two more appear.



  













 

nicholas bonham-carter

the great flood

is there any auto-fill on this system which caused the over-filling?

the small diameter of the supply pipe might be evidence of a vapor system, needing very low pressure. do you have a good low-pressure gauge on the boiler [0-3 psi gaugestore.com]? high pressure from a blocked pigtail could back the water up into the returns, causing a temporary low water condition, and subsequent over-filling.

why not get a copy of "the lost art of steam heating" and give it to your service company, so they can be better informed about venting, pressure, etc?

in a hybrid system like this, i guess you have to treat each part separately-the 2-pipe has certain requirements [traps etc.] and the 1-pipe part needs other things.

get those pipes insulated, if only with fiberglass bats as a temporary measure!--nbc

DavidK_2

boiler room flooded

Can you tell where the water is coming from?

Jamie Hall

The question is...

where is the water coming from?  My first thought, since this seems to have happened after you got that lovely radiator working, is that the problem may be somewhere in the return from that radiator.  After all, when you think about it, you did't have the flood before that radiator started working -- and a big radiator can produce a lot of condensate.  It is quite possible that there is a rusted section of the return; it may not be obvious when the heat is off if the return is dry (if it's a wet return leaking, you'd know it!).  Check the entire length of that return for starters.



If the boiler water level is OK, and you seem to suggest that it is, at least you know that the autofill is working!



I'm not saying that the leak has to be there -- just that that is an obvious place to start.



As to the system struggling to come up to temperature starting at 50, have to admit that I'm not all that surprised.  There is a world of difference between holding a temperature, or recovering from a small setback, and coming a long way up.  However, that said, the lack of vents and the uninsulated pipes aren't helping you any.  Somewhere on either the dry returns or the mains for the two pipe section there have to be vents.  Exactly where differs from system to system, but they have to be there.  Likewise, on the one pipe section, there should be main vents at the ends of the mains.  If there aren't, all the air has to leave through the radiator vents, and they aren't meant to do that.  A lack of insulation usually results in excessively long times to get heat to the radiators, if it gets there at all, as the steam is condensing in the mains.  This can also cause water hammer, but it doesn't always.



You might, after you get done insulating things (and finding the leak!), take a little time for yourself and make a sketch drawing of the system, showing the mains and returns and radiators and all the traps and vents.  Just as an exercise for learning the system.  Pay particular attention to traps.  In general, one pipe systems don't use them; if they are on that section, it may pay to figure out what they are for -- they may or may not be needed.  Two pipe systems usually do have traps, but equally usually only at the radiators and, on some, on crossovers from the steam mains to the dry returns.  Other traps on both systems may have been added later to "fix" problems, and in those cases the cure may be worse than the disease.



Also while you are at it, check the pressuretrol settings -- neither one pipe nor two pipe systems need to run over 2 psi, and less is often better.



But do do the insulation, add some vents where they should be but aren't, find the leak, and keep us posted on how you go!

helpJohn

condensate tank overfill

i was away from the situation for about five hours.  floor was beginning to dry.



the condensate tank was totally filled and i think this is where the water on the floor came from.  i lowered the water tank level ( it has an automatic fill ) and let out some water from the return lines.  boiler is firing nicely - not cycling as much and the rads have calmed down some ( not spitting, etc. )  i have not yet made the connection between too much condensate and cycling ( if there is one to be made ).



the condensate tank pump periodically turns on and fills the boiler.  how does it know when to do this?  seems like it could flood the boiler.



will have to rip down a lot drywall to insulate the pipes since they are tucked in soffits.  first i will check for the main vents since i most curious as to where they could be located.  would lack of main vents affect boiler cut-out pressure in any way?  that is to ask, would lack of main vents cause the cut-out pressure to be reached more quickly versus if they were installed?



thinking of pulling the traps.  there are about twenty of them throughout the system and they complicate the diagnosis of problems.  the 2 pipe rads do have traps.  will consult a steam pro about this although they certainly are difficult to find.



nbc, funny you should suggest that.  if fact,  i did purchase dan's "lost art" book and did give it to my serviceman.  have not heard from him since.  hope i get it back soon or someday.

Jamie Hall

Some comments

First thing that hits the eye -- yes indeed, lack of main vents could easily cause pressure to build unduly rapidly.  As well as uneven and slow heat.



Condensate return pumps are, IMHO, a pain.  Unlike boiler feed pumps, which turn on when the boiler needs water, condensate return pumps are completely witless, and turn on -- or are supposed to turn on -- when the level in the condensate reaches a certain point.  Usually a float switch.  As a quick guess, is it possible that the float is misadjusted?  Or doesn't float any more?  Or that the switch is shot?  That could certainly cause a flood!  Particularly if the autofill is industriously doing its thing in the meantime.  If you get a steam pro in, he may be able to convert the thing to a boiler feed pump set up instead.  They work a lot better.



Extra traps complicate everything -- and it is not uncommon to find that they were put in to "fix" a problem -- see me comment above!

helpJohn

ahh! F and T steam traps are serving as the vents!!

looked for vents on the main - none to be found.  jamie mentioned there had to vents somewhere and either jamie or someone else said there had to be a reason why these were installed.



came across this on the Hoffman site:







"Float and thermostatic traps have two basic elements: a



thermostat for venting air from the system during start-up



and a float assembly for draining condensate."





so the thermostatic aspect of the trap is venting the air into the return line acting as main vents.  that is why the traps are on this one pipe system.  btw, some are near the mains and all the rads do heat up.