Water being drawn up into the main - 2 pipe system

heatseeker1

I have reason to believe that the main is retaining water. A lot of hammering is happening at the boiler on the outer wall immediately adjacent to where the main starts its run through to the supply pipe. A Hoffman vent was removed this summer from what I was told was the return. Could they have removed it from the wrong line? Now that I've gone into the garage I can see that they removed it from the supply line. Sorry for the bad pics, but the 3rd picture is the location where the vent used to be.

KC_Jones

If you have hammering, that is caused by water laying in the pipes and the steam picks it up and "hammers" it into a fitting. Check the pitch of all the pipes and make sure they are all pitched in the correct direction. On a parallel flow the highest point should be at the boiler and everything pitches downward from there. On a 2 pipe system the vents are usually at the end of the dry return many times that is near the boiler somewhere. What vents do you have left after the removal of that vent?

heatseeker1

None. I take that back.. Years ago some non-plumber, non-heating person attached a small hoffman on a radiator. He thought it would decrease the banging at that radiator.

Jamie Hall

Could you stand back a bit further from the boiler, and take a photo with all of the near boiler piping included? Any risers, the returns, all that stuff. May take a couple of photos from different angles. I'm having a little trouble making out what I see of the piping, and before I sound off on what I think I see I'd like to see it more completely...

On vents. Why was the vent removed? Seems an odd thing to do. If that was a dry return from which it was removed, it -- or more likely a bigger one -- is going to have to go back there. The dry returns have to be vented.

In addition, the steam mains have to be vented -- either with vents at the ends away from the boiler, or through crossover traps -- also at the ends away from the boiler.

On the hammering, the first thing to do is to check the pitch of all the pipes. Any water when gets into a pipe (and it will) has to be able to drain out of the pipe and into a wet return or back into the boiler. That's rule one. If there any low spots, or a section of pipe which has no drain at the low end, you will get hammering.

heatseeker1

The vent was removed because during the heating season it was spitting water and steam like Mt. St. Helens. Does that mean that it was broke? There is a very old hoffman on the end of the run on what appears to be the wet return stuffed way back in the corner. Don't know if it's functional or not. I apologize for the bad pics. The boiler is in such a tight area that I can move far enough away at any angle to capture the whole set-up.

heatseeker1

When steam becomes condensate and leaves the radiator through the trap, what's the name of the pipe that carries the condensate back to the boiler? Does it return to the boiler as water? Is the wet return the pipe running along the basement floor? What is the name of the line that takes the steam from the boiler to the radiator?

nicholas bonham-carter

Steam travels out of the boiler through the boiler riser, into the horizontal header, and from there into each of the steam mains, each individually connected to the header.
Once in the main, the next stop is the radiator, where it condenses (condensate), and flows out through the radiator trap into the dry return. Next stop is the crossover traps allowing the water to then pass down to the wet return, and back to the boiler.
The steam books in the shop here would be a wonderful investment for you to have, and you would end up knowing more about steam heating than many average plumbers.--NBC

heatseeker1

Interesting! I wasn't aware that there was another trap beyond the one at the radiator. Thanks for knowledge. I ordered one of Dan's books which should arrive shortly.

Jamie Hall

If the vent was spitting water and steam... at that location... your pressure is way too high and at least one radiator trap or crossover trap is failed open.

Fix the pressure first -- cutin on a pressuretrol should be around .5 psi (as low as it will go).

heatseeker1

Thanks Jamie. My pressure reading gauge on the boiler is bustded. The neefle sits at 5 even when cold. When the boiler is in heating mode the needld rises to about 7. Righg now the boile isn't on and the needle is on 7. Everything about my system appears to be shot. The pressuretrol. on 0.5. That's probably broke too even though it was replaced 4 weeks ago.

nicholas bonham-carter

Even when the supplied, and required 0-30 psi gauge is working perfectly, it is useless for the diagnostics we need for perfect operation.
Your two-pipe system is one of the best for comfort and economy, so get a valworx 0-3 psi gauge, to see if you also need a vaporstat. Keeping the pressure down in the area of mere ounces will save fuel, and make you more comfortable.--NBC

Jamie Hall

heatseeker1 said:

Thanks Jamie. My pressure reading gauge on the boiler is bustded. The neefle sits at 5 even when cold. When the boiler is in heating mode the needld rises to about 7. Righg now the boile isn't on and the needle is on 7. Everything about my system appears to be shot. The pressuretrol. on 0.5. That's probably broke too even though it was replaced 4 weeks ago.

Does the pressuretrol ever shut the boiler off, or does it just keep on cranking? When the new pressuretrol was put on, did someone clean out -- or better, replace -- the pigtail (with brass!) and the opening in the boiler it screws into? Surprising how often those get gunked up.

That 0 to 30 gauge is required by code, but doesn't help you much to see what's happening. It is possible to put both the pressuretrol and a new low pressure gauge, as suggested by Nicholas, on the same pigtail. Not a bad idea.

I doubt that everything is shot -- but I'd venture that there are a number of things which do need attention. Don't despair. We'll get there.