WHAT ARE SYMPTOMS OF CLOGGED RETURN LINE ON LONG MAIN SIDE OF ONE PIPE STEAM SYSTEM?

ww

I read the article below regarding the subject and have gathered some great information. I ran my hand along the short return line and it was hot from the main to boiler.

The long side under the main was hot and just warm by conductivity going toward the boiler. I notice the water line at the boiler glass goes up and down a bit when boiler is running. I'm having various problems with radiators heating up all the way on the long side and wondering if this may be part of the problem.

I see unions so I'll be able to take a look and see if lines are clogged up. I do notice the long side return on the floor has some heavy rust..and the other short side is pretty clean.

Reasons why the return lines are clogged, and where to look for solutions
SHARING

Published: June 25, 2014 - by Dan Holohan
Categories: Steam

Jamie Hall

I'd be much more concerned about the short line which is hot... but this is one pipe steam, so perhaps not.

The chief symptom of a clogged return line is slow return of condensate to the boiler, such that, when the boiler fires up the water level drops significantly during a cycle and stays down, and only comes back slowly at the end of a cycle.

The radiators having problems heating up on that side are much more likely to be related to a lack of (or inadequate) main venting on the steam main on that side.

DanHolohan

What Jamie said, and if it's clogged enough, you're liable to get water hammer toward the middle of the firing cycle as water backs up into the steam main.

Abracadabra

If it's partially blocked, you might get boiler flooding as the boiler makes steam and condensate doesn't return as quickly as it should. Level drops, and feeder feeds fresh water. After cycle is over, the partially clogged return slowly always the backed up condensate to return to the boiler. Ask me how I know!

ww

ok thanks..there is no water hammer or lack of water while cycling...i'll see what happens...i'm trying different vents in radiators now...
reading the venting guide for radiators as well.

i made antlers and used a gorton 1 and 2 on long main and hoffman 75 and gorton 1 type on the short main so the mains vent out really fast...maybe i need more vents..set the pressuretrol cut in .5 and 1.5 differential.

maybe when i figure out the vents things will change on that return. i flushed the boiler last week a few times and it's totally clean now.

ww

i now understand more as to why you have to put these main vents 15 inches back of the 3/4 inch hole on the main..the water that is at the boiler level below that pipe would be subject to block the vent eventually with rusted debris and water as well when the steam heads down the main pipe from boiler

i also see the difficulty regarding clearing the return lines as well.
i will have to get some large enough hose to put over the connection at the union and put that hose into the floor drain and run a hose.

if i carefully fill the boiler and allow the water to get into the main line and flow back around to the return line i'm wondering if that would be a start to check the flow..

of course watching not to fill to0 high and go out the radiators. i could leave the boiler drain on and if the water comes out really rusty maybe that would indicate the return lines are being flushed. if that doesn't work i could always disconnect the unions after draining the boiler and flush it out and run a snake through there.

i guess if the line was clogged it would have to be replaced anyway if i couldn't clear it out another way. i don't want to be presumptuous but since i get no water hammer and steam heats the mains i'd figure there is no water blocking the mains.

ww

update...i removed the antlers on both sides and checked the site glass at boiler..it was half full. i put the hose on and let the water flow through the 3/4 hole and observed the site glass and level increased. I checked the other side as well. i continued this operation for awhile with the boiler drain on to flush out the returns.

i filled the boiler to the proper level and fired up the boiler. today i put in # 5 maid o mists on the lower floor living room above boiler and hall..and in the back room a #6.

two top floor front rooms i put in 2 #5's. the back room a # 6 and the bathroom #5. radiators started to heat up...some unevenly and cold in middles...a couple hot all the way and bathroom cold. I broke the union on radiator and it started to get hot after that. There is some air lock or something going on. i know when steam hits the cold radiator it condenses and creates a vacuum.

so this still needs more looking at. any suggestions on what to put on? Gerry Gill says he starts with all c's and takes it from there. I'll try that too..i did but some of the c's may have been bad so i have some more.

How is that determined what vent you put and after observing what? it seems these radiators reactions change drastically according to what vent is in but the problem is you take from peter and give to paul and i'm not satisfied yet as a whole.

I'm wondering if i need more main vents on these antlers. do the main vents have anything to do with removing air on branch lines or it stops there and that is handled by radiator vents?..i noticed on some one pipe systems there are vents on the return lines too.

i've read that the site glass should be half..others say 3/4..is there a difference in steam production,pressure,etc at different levels?

Jamie Hall

Getting the venting right on a one pipe steam system can be a bit tricky, and is almost guaranteed to try the patience. However, if your main vents are adequate it's easier -- and the best way to make sure of that is to look at the time elapsed between when the first radiator gets any steam at all (just a bit of heat at the valve) and when the last one does. That time should not be more than about 1 minute for every 10 to 15 feet of main (assuming that the main is insulated -- no insulation? It may take a lot longer, and that's not a venting problem).

Once you are sure of that, then you can start fiddling with radiator vents. You will get there.

From what you have written, I doubt very much that you have a serious clogging problem on a return. It may be a bit grungy, but clogged? Probably not.

You ask about proper boiler water level. Most boilers, about half way up the sight glass is as good a starting point as any. However, assuming that the near boiler piping is good, neither higher (up to 3/4 or even higher) nor lower (down to a quarter) will make much difference in the way the boiler steams or its efficiency. Always assuming that the water level is reasonably steady -- not bouncing more than an inch or two.

ww

ok jamie, thanks. it seems then that since i have about 40 foot of 2 inch main including what's on the boiler then it seems it's taking alot longer and steam doesn't get near the radiators in 3 minutes..and the main pipes are insulated..not the branch ones..so i'll think maybe i need to do something to speed up that steam getting to all the radiator valves in under a few minutes...will try to do something.

i guess what i'll really have to work on now is the reason it takes so long to get to the radiator valves...any suggestions would be appreciated.
thanks