Leaking Steam pipe in 2nd floor Unit

Nate30

Hi All,
I have recently learned a great deal about steam heat because of the issues I have been having with the second floor unit I rent out. A month ago we noticed that our ceiling under upstairs radiator was dripping water slowly so we brought our heating guy over. I explained to him that before I rented it I noticed rotting wood by the radiator supply valve. He said the union valve was hand tight prob from when they did the floors. We tested the heat and didn't see a problem till this week.
This week I noticed the same thing again so I put paper towels by the supply valve, the union and air vent. I also slightly pitched the radiator with two pennies. Well two days later we noticed the leaking again, and it always seems to be at 4AM when it happens with banging. When I went upstairs I saw the paper towel near the supply valve completely dry but the air vent was letting out water (from both sides?) more than I have seen it do that before. I pitched the radiator more so the bubble is all on one side and I plan to replace the air vent when the supply store opens. In the mean time I cut my ceiling to see the pipe from the floor. The radiator pipe goes into an elbow fitting which has another pipe run across my rooms ceiling. I felt around my ceiling and noticed one hot point in the middle of the room(just an observation). They have been losing water a lot(another ovservation).
From what I can see the elbow looks to have some micro cracks that are letting up but i need some advice to know if they are actually cracks or not. I can't see the thread to the pipe which goes up to the radiator but there is still a chance t is leaking from there, which is still below their floor. Not sure if that could be causing the floor to rot again which is what I'm noticing. Maybe the blow off steam and moisture from the connection below the wood floor is damaging the wood?
Either way, would like some advice on how to proceed. I'm new to this but don't feel so overwhelmed. The boiler is a riello with Weil McLain. Thank you in advance for your suggestions.

nicholas bonham-carter

“Water water everywhere and all the boards did shrink”
Your system pressure may have crept up due to the pigtail having become clogged, preventing the pressuretrol from being able to see the pressure. This may be due to dirty water, or some additive to the water in your system. Unfortunately the standard 0-30 psi gauge is useless at showing the few ounces of pressure needed to get steam from the boiler to the radiator. A 0-3 psi gauge would be a good addition for you.
Cleaning the boiler, which may never have been done, is too time consuming for this very cold weather, but you could drain and refill if the sight tube looks opaque instead of transparent.
At the same time the pressuretrol could be unwired enough to take the pigtail off and run a cable tie through it to make sure it is clean.
Check your main vents to see if they are large enough to allow the air to escape with low resistance. The radiator vents are not large enough to do this, and if they are the main escape channel for the air, a lot of water, and debris will be carried up into the rads, which you do not want.
Do that first before assuming you have a leaky pipe. When you get it running right again at low pressure, the put a paper towel under the pipe, above the ceiling to see if it gets wet, or watch it while firing to see if any steam comes out of the “cracks”.
Dirty boiler water, and bad venting is the Albatross around our necks with these systems.—NBC

Nate30

Hi thank you for your response. What should the pressuretrol be set to, the lowest setting? How would I check the main vent and can you be more specific about what the pigtail is? I attached a photo of the sight tube because the water looks clear but it looks like the tube has some brown color covering part of the tube .Funny thing is I haven't seen any leaking since I cut the pipe a few days ago. I notice a drop or two but nothing else .