After New boiler installation - loud banging and hissing

alex_11

Background: Original coal fired boiler converted to oil. System was working fine heating around 1300SQ ft. No banging and hissing.All radiator has original vents.Everything was working fine,since we bought this house 9 years back. For the last nine years no issues.



One month back got the boiler replaced with a brand new gas fired steam boiler,properly sized to the sq ft of radiation.



Piping: Original piping had only one riser and surprisingly NO main vents.System worked beautifully with no issues. Only one main and one main return - length around 30 ft from the boiler. Boiler is on the opposite end of the house. All radiators feed from this main and risers are teeing off at 45 degree elbows.No issues no banging no hissing.



Problem: Since the gas boiler replacement, suddenly I hear loud banging in different radiators during the first 20-30 minutes of the heat cycle. Whichever radiator is banging eventually starts spitting.



Piping has not changed than why are the radiators hissing. There was NO issues before the new boiler installation.



I have verified that the radiators are all pitched correctly and the pitch in the return and main is correct.



Can some one tell me what could be wrong. The installer is very professional and would like to fix the problem but he is at a point where he has no clue.



Please advise.

Thank you so much.

kcopp

few things...

Piping? Done to  specs? Was it flushed and skimmed of oil pipe dope, etc? Got pictures? Is the boiler in the same place as before?

Mike Kusiak_2

Near boiler piping

Can you post some photos of the boiler and the piping connecting it into the mains?



Do you have a proper header and equalizer? Was the boiler piped according to the manufacturer's  installation manual?  Modern steam boilers are very critical as to how they are piped into the system, and what worked for the original coal boiler may be unsuitable for your new one.



You might get more responses if you posted your questions with some photos in the "Strictly Steam" section of the Wall. Thats where most of the steam guys hang out.

JK_3

What is the pressure set at ?

To high of a pressure could definitly cause this kind of problem.  In one pipe systems too high a pressure will not allow the condenste to return down the pipe properly forcing the water back and causing hammer and spitting. I have also seen radiator valves that were closed partally ( to try and limit heat ) have the same effect.

furnacefigher15

There are a few key

Elements that have to be installed exactly right, in order for the boiler to work right, and the big ones are height of the water line compared to the old boiler, height between the water level and the steam header, using both steam outlets from the boiler, operational pressure.



I would first try turning the pressure to cut out at 1.5 psi or less. If the problem goes away, leave it alone. If not, something was not done right.

Jamie Hall

Two things immediately come to mind

pressure.  That willl surely do it, pretty well guaranteed.



Waterline. may or may not, if it is significantly lower than the original.  That depends on whether there were wet returns, and whether they are still wet.



If your man is really good, and the boiler was installed according the manufacturer's near boiler piping specs, I'd bet on one of the two above.