new steam oil fired boiler problem deperate please help

joe45

recently had a boiler installed.  the thermostat is set to 70 in the morning. it reaches 68 and then it shuts on and off every 2 minutes till it reaches 70 degrees for about an hour.  so....  they came and adjusted it now it shuts off when it reaches 64 degrees and starts cycling every 2 minutes for an hour.so when that didnt work the company came and downsized  the boiler cuz they said it was producing too much steam.and was oversized we have a 1500 sq. foot home and the steam sq.ft. of the boiler now is l 283 h 350  now we have the smaller boiler and it does the exact same thing also the pipes bang when we didnt have that problem ever not sure what to do please help 

joe45

also

also its a one pipe system

Jamie Hall

Hard to say even...

where to start.  Without being there.



You that initially the boiler would reach 68, and then cycle on and off every two minutes or so until it reached 70.  Do I assume that this implies that you are using a night setback?  Steam is not really happy with setbacks; I would suggest that a maximum setback of 3 to 4 degrees is about it; anything more and you may be wasting fuel bringing the house back up to temperature.  Check that for starters.



The initial behaviour you describe may be more or less normal steam system behaviour coming out of a deep setback.  The boiler gets the system full of steam and then, rather than create pressure -- which does nothing except burn money -- shuts off for a bit.  Then comes back on, and so on until the thermostat is satisfied.  Without knowing how long it took the boiler to go from start to when it started cycling, can't tell much.



Next.  The only way -- the ONLY way -- to properly size a steam boiler is to add up what is called the "EDR" of all the radiators in the house.  There are various ways to determine the EDR of the radiators -- hopefully someone will chime in with the correct link.  Then the boiler is sized based on that.  There is no other satisfactory way to size the boiler.



So... We need to know the total EDR of the radiators in your house, and the EDR rating of the boiler, to make any sort of comment on whether the boiler is too big, too small, or just right...



Pipes banging is probably water hammer.  Any number of causes for that, but if it didn't do it before the new smaller boiler was installed the first place I would look would be the install of that boiler.  Two things: pressure (maximum 1.5 to 2 psi, never more) and near boiler piping.  Which must be done as the installation manual directs.



Could you take some pictures of the boiler installation?  Until we see those, there isn't much to be said about the near boiler piping.  But it is critical...



Hope this helps get started...

joe45

thank you for the reply

thank you for the reply its a smith boiler series 8 not sure of the edr have to find that out. when we go to bed we turn the heat down to 62 and in the morning turn it up to 70 and thats when it happens. it does it thoughout  the day but the worst is the morning. the I=B=R net ratings are steam mbh 84. hope this helps i will find out the edr

joe45

also

i have checked the piping diagram with the boiler and everything looks exactly like the diagram .the thermostat was bypassed to make sure it wasnt faulty and it was fine

BobC

System issues

Joe,



Your new boiler should be operating at or below 2PSI, check the pressuretrol and see if the outside tab is set to 0.5 and then take off the cover to see if the white dial is set to 1 (one).



What kind of thermostat do you have? For steam it should be set to 1 or 2 cycles per hour. As Jamie said you don't want a deep setback on a steam system.



Your main venting may not be adequate, what kind of main vent do you have? How long is the main and what size pipe?



Has the new boiler been skimmed yet? A new boiler is usually skimmed a couple of days after being installed to remove any impurities in the water. Does the water in the sight glass bounce up and down a lot when it's making steam? that indicates it might need to be skimmed.



Post some pictures of the boiler, the near boiler piping (front and back) and the main with the main vent.



Bob

Jamie Hall

Too much!

Ok -- whatever else we have here, that 62 to 70 setback is just too much.  I'd suggest half of that, or less.  I have kept records over a number of years on the building I superintend (northwestern Connecticut)(a sort of museum), and I have found that a setback over 4 degrees costs us money, not saves it (we run 62 to 66).



That said, the behaviour of your original boiler in its original state (when it was shutting of at 68) (not the newer littler (?) one) is exactly what I would have expected: the boiler ran for quite some time, until it filled the system with steam.  Then it cycled -- just as it should -- until the thermostat was satisfied.  The hour or so running time for that deep a setback sounds pretty much reasonable, too.  I hate to say it, but it doesn't sound to me as though there was a significant problem with the original setup, but it does sound to me as though the "remedial" work which was done made matters worse.



I do suspect that there are problems other than the new boiler here (I definetly suspect the new boiler has some kind of problem -- pictures pictures please).  As BobC notes, there may be venting problems; pretty common, pretty inexpensive to fix.  He's also quite right -- independent of whether the new boiler was piped correctly, was it properly skimmed?  Is it set to the correct pressures?



Wish I could dial back to where you started... and go forward from there, to be honest.