Steam Heat Issue - Water spraying from radiators

gkennedy61

Good morning. I’m not a plumber but a homeowner trying to figure out an issue with an old steam unit. Basically, we bought an old house a little over a year ago. It has a complicated heating system that includes a steam unit that heats 8 radiators throughout the house (4 on the first floor, 4 upstairs), as well as a separate forced air system. Some are one pipe and some are two

The issue we have had is that we have now twice (once last winter and once this) had problems with water spraying out of one of the steam radiators through the air valve. And when I say spraying, I mean like gallons of water, not just a little trickle. Each time, this has happened unexpectedly, and the one way to resolve it is to empty water from the steam unit itself (a Utica which our heating guy says is in great shape).

But the thing is, there is a LOT of water in the unit when I do this. Not just a few gallons - the last time this happened, I dumped out roughly 18 4+ gallon buckets of water (that is not a typo) before the site glass on the steam unit came down to the appropriate level. There also seems to be some leaking from the boiler itself whenever this occurs, as there is water on the floor of my boiler room.

Part of the issue seems to be that condensate is not making it back to the steam unit and it needs to be refilled periodically. That said, I’ve never refilled it anywhere close to the amount of times that would lead to even a fraction of the amount of water I pulled out of the system. (And we switched the primary heat in the areas where we have steam to forced air, meaning that we have to use the steam unit a lot less now, other than when it’s bitterly cold).

Piecing this together, it seems like there is some backlog of water forming in the pipes as water does not return and, at some point, the backlog just rushes out to flood the steam units and the pipes, leading to the water spraying out of the radiator valves. I am curious if anyone has seen an issue like this before and has any thought on what the problem might be. We had a someone come out earlier this year and he was a bit stumped and wanted to see how it proceeded for a bit (unfortunately our legacy heating guy passed away this summer). Much appreciated.

KC_Jones

If you aren't adding the amount of water you are draining, then it's not a slow return, the water has to be added somewhere. Now you could also have a slow return, but I would suggest first thing is to figure out where the excess water is coming from.

Do you have a separate water heater, or does the steam boiler make the domestic hot water. If it does then you could have a leak in that coil.

Another likely possibility is the valve for adding water has partially failed and is leaking water by.