complete system purge/reset question

No_Caller_ID

i have a good amount of experience with hot water boilers, but steam not so much. i have found some answers i wanted but i am hoping to find more precise info to help my friends situation, so let me explain his unusual setup....

its a very large home that has steam boiler heating everything but attic, the previous owner had a furnace installed in the attic that also has central ac, and they ran new duct lines to the 2nd floor rooms as well as the attic obviously. after doing that they cut the feed lines to 2nd floor radiators [2 pipe systems with steam traps]. so basically in winter time he was forced to run the boiler AND the furnace to keep whole house heated. also, he always had banging in the radiators.

at the end of last winter i reconnected the cut pipes for him so that he could use only the boiler for heat [attic would be somewhat warmed from rising heat] so fast forward to this year, upstairs radiators not getting hot some in fact freezing cold. so he uses furnace as well since ductwork feeds these rooms and never bothers me. well then the board on his furnace went out basically leaving all bedrooms now freezing.

so i go take a look, first thing i notice is pressure gauge is 0 or even below it actually. there is an auto feed valve connected with a manual override. the glass tube was "full" so i drained just a little of water from system and it dropped to half full. so i then decide to work on easiest to access radiator...i set boiler to stay running and try to 'bleed' the radiator. it has standard feed valve on one side and steam trap on other, as well as 1/2" plugs in top section of rad on each side. so i removed the plug on the steam trap side with boiler running. i could hear some pressure building but very little and after 10-15 minutes nothing reached the radiator. so i decide to force fill a good amount of water into boiler, but gauge still did not move [possibly broken?] anyway, now i can hear and feel the air trying to reach this radiator. few minutes later pipe on feed side got burning hot so i prepped to replug the other side. as soon as i felt the steam coming i tightened up the plug, the entire radiator was extremely hot now. at this point all rads were burning hot and i had hoped that the problem was partially solved, i had a feeling i may have to do this to all the other rads that were disconnected years ago but i figured i would let it run to see if there was any improvement. today they say rads cold again and even noisier than usual.

so now instead of just trying ideas i came here looking for help so i dont keep wasting time doing things that might not help. my goal is to get the system running as efficiently as possible or as its meant to be and understand it all better. attached are a few pics i took that may clear up some things in case i typed wrong, thanks in advance for any help.

Jamie Hall

Oh boy. Steam systems are not anything like the same a hot water systems, and it sounds as though you are applying things you have in mind from hot water systems to steam. The result can be anything from a poorly operating system to catastrophic damage to the system -- and serious personal injury to the workman.

Steam systems do not need bleeding or purging or anything else of the sort. Before you do anything else to the system, you absolutely must get either "The Lost Art of Steam Heating" or "We Got Steam Heat" -- available from the store on this site, or from Amazon.

In the meantime, while you are waiting for the books, on the front of the boiler you should find a glass tube. It should show the water level in the boiler and that should be about half way to two thirds of the way up the tube. It should respond to adding or draining water. If it doesn't respond, it will have to come off and have the connections cleaned -- assuming the valves connecting it to the boiler are open. If it does respond, drain or add water until the boiler water level is where it belongs and then leave it there.

With any kind of luck the extra water you added will drain back to the boiler, which should take care of some of the banging.

Then adjust the cutin pressure on that blue grey box to 0.5 -- where it is is much too high.

Do not expect pressure to show on that gauge when the system is running properly. It shouldn't.

If a radiator on a two pipe steam systems stays cold, there are a number of possible causes -- reading one of those books should help you analyse them -- but for the moment leave it that there could be water trapped in a poorly pitched feed pipe or return pipe, or the inlet valve could be closed, or the trap on the outlet could be failed closed, among other possibilities.

And last -- taking a plug out of a radiator with the boiler running is extremely dangerous. Once steam reaches the radiator, you will get steam coming out fairly soon -- and steam will cheerfully give you second or third degree burns in a matter of seconds.

No_Caller_ID

ok thanks for the your help and the info, i will read up some more and adjust the feeder as you said. i knew that my hot water system knowledge was all i had to work with and thats why i resisted my urge to keep fiddling. i am familiar with the glass tube, and that was what i used to measure how much to drain out originally as it was full, and i knew it should be about half full [of course now its full again after the extra added water)

my biggest concern is that there was some kind of issue discovered with these radiators before, and thats what caused previous owner to cut the pipes to them.

Jamie Hall

No_Caller_ID said:

...
my biggest concern is that there was some kind of issue discovered with these radiators before, and thats what caused previous owner to cut the pipes to them.

May well have been -- but two pipe steam is, basically, pretty darn simple. One reason some of us really like it! Basically so long as the pipes are pitched so that condensate doesn't build up and the traps are working... that's about it. The previous owner may have had some idea of saving money by disconnecting those radiators (he wouldn't have, but that's another story) or he may have had a water hammer problem (bad pitch in a horizontal pipe somewhere) or... just plain perversity.

I really do recommend The Lost Art -- very well written, and very clear.

BobC

It sounds like the system can'y get rid of the air in the pipes on the second floor, steam cannot flow until the air is pushed out. That green vent looks like the only(?) way the system cann vent the air, make sure it's working. If there is any doubt replace it with a Bigmouth vent (4X the venting capacity as the Hoffman 75)

In one picture you show a Hoffman #17steam trap at the end of the cast iron baseboard, if that trap has failed shut steam will never enter the baseboard because the air can't get through the failed shut trap - steam can't get passed trapped air. A steam trap stays open till steam hits it then the hot steam will close the trap. If you remove the top of that trap you can examine the trap element, you can get new elements from Barnes and Jones. Look aroung the basement and see if there are any large traps on the piping.

Two pipe systems want to run at very low pressure so set that pressuretrol front tab to 0.5PSI and behind the front cover you will see a white wheel and that should be set at 1 or lower.

Bob