having a problem with a steam boiler

Jepo

I have a two pipe heating system, I have 1/2 inch steam traps on all radiators, I replaced the boiler, now Im having a problem, all my feeds to my radiators are hot, but my returns on the radiators are ice cold. I replaced all the 1/2 inch steam traps and my returns are still ice cold except for one radiator. It is a free standing radiator the rest are sun rads. can anyone help me.

Al Letellier_21

new boiler

Sounds like a piping issue. Did the water line change when the new boiler was installed? Pressure different than before? Do you have a condensate pump or are the returns tied directly into the boiler? A two pipe system needs twice as much "A" dimension so the water line is critical.......

BobC

Installation manual pipe diagram

i assume things worked reasonably before the new boiler?



What make and model is the boiler/ Post some pictures of the boiler and the piping around it from a few different angles so we can see what your dealing with. Also look in the boiler installation manual and see if your piping agrees with the piping diagram in the manual.



Bob

Jepo

steam boiler

when i take off the 1/8 plug alot of cold air comes out and then all the radiators get hot, it works for a couple of days and then they stop working. it doesn't have a condensate pump.. do u have any suggestions. its been driving me crazy.

Jamie Hall

Clearly...

if you take off the 1/8 plug on a radiator, and air comes out, and the radiator gets hot... the air can't get out in the normal way.  Which may be vents on the returns, or it may be that you are getting steam pressure into the returns.



With a new install, I'd look at two things right away: were any vents on the returns removed for the new install ("we don't need those any more") and as Al said, was the water level changed?  That is actually a very very likely possibility.

Dave in QCA

Venting of Returns Required on 2-pipe

In a 2-pipe system, the return piping must be vented to the atmosthere in some manner, either through a condensate receiver pump/tank, or through a venting device of some sort.



When the steam starts to travel out from the boiler, it will approach the inlets of each radiator.  In order for steam to go in, the air must go out.  In order for the air to go out, it must be able to pass though the trap and on through the return piping where there must be a way for the air to escape from the return piping to the atmosphere.  If the return piping is sealed, you will get no heat in your radiators.



A dimension and B dimension is an issue on a 2-pipe system, but has no bearing until pressure begins to be established.  Since steam is not even making it into the radiators, this lack of steam cannot be caused by an improper a or b dimension.  Howeveer, those need to be examined to make sure that the piping was not messed up, because it seems that the installed may not have understood the physics of 2 pipe steam systems.



I person posted a thread on the wall a few months ago, where his installer told him that he did need any main vents, or vents of any kind on his system, because it was a 2-pipe system.   So.... 



More information and pictures of your system will enable the folks on here to help you identify and resolve your problems.