Post system overfill and flood, increased water hammers

abea17

Just over a month ago my steam system overfilled and flooded my pipes. I know water was in the pipes on my first floor, I’m not sure if it was able to get up to my second floor radiator. Either way, since that happened, there have been more water hammers in my system, especially on the second floor radiator which is also panting (inhaling and exhaling air during the heating cycle). I haven’t noticed panting in any other radiators. After the overfill, I had my boiler serviced and everything else is working properly, apart from the noise and issues with my upstairs radiator. I was able to come to the conclusion these issues were due to the flooding after reading Dan’s article on water hammers. Dan recommends disconnecting the riser and flushing the lines to clear any sludge. However, I have no idea how I would do this. My upstairs radiator piping is completely enclosed and I cannot access it, apart from where it connects to the radiator. Does anyone have any experience with doing this, or any idea how to approach this problem?  https://heatinghelp.com/systems-help-center/what-causes-water-hammer/

EdTheHeaterMan

I have heard in the past that when a horizontal pipe that is designed to hold only steam and a very small amount of condensate, gets filled with water, that pipe weighs a lot more and the hangers in the basement may not be able to support that extra weight. After you remove all the water, if the pipe is no longer properly pitched as a result of the flooding that happened earlier, there may be some sections that are holding a significant amount of condensate pooling in low points that were not there before the flooding event.

Look at all the pipe hangers in the basement that are supporting the Main(s) and see if you can tell if the pipe has dropped even just a 1/2". That can make all the difference in the world. Do you have a 3 ft level? use it on the main pipe(s) to ensure they are properly pitched so the condensate returns to the boiler properly.

Jamie Hall

I'll just extend @EdTheHeaterMan' s advice to ALL near horizontal pipes you can find. Long runouts especially. And be alert for sags, as well as any end to end problems.

It's unlikely that the problem is "sludge" or something of the sort, but if you still have the problem after correcting any out of level points or what have you you can get access to the top of any riser simply by undoing the union holding the radiator to the inlet, moving it aside, and running water into it.

The panting you mention does indicate that there is a condensate puddle trapped somewhere in the line to that radiator.

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1831956#Comment_1831956

I like extensions! Thanks Jamie

abea17

Thank you both for your advice, I will be checking with a level this week! Jamie: there has been a condensate puddle in the line for as long as I have owned my home (4 years) so I have always heard water moving and had issues with it getting as hot as everywhere else. However, I’ve never dealt with water hammers to this extent in that radiator, or heard panting from the vent. My boiler tech said years ago that the only option was ripping up my floor to access the pipes. Do you have any experience dealing with trapped water?

Jamie Hall

Oh indeed I do have experience with trapped water. But it's not hard to fix — assuming you can get at the piping. The solution is to make certain, by adding or adjusting hangers as needed, that the pipe has an adequate pitch end to end — and just as important, that the pipe has absolutely no sags anywhere in it. You can either use a laser or a taught line from end to end to check that, and particularly if the pitch overall is relatively flat this is really critical.

Any relatively short sections also have to have a useful pitch — and this can be problematic when it is a short offset between two vertical risers, or off a vertical riser over a few feet to a radiator.

abea17

Unfortunately this is on my second floor, and the piping is completely enclosed, so short of ripping up flooring, I can’t access it.

ethicalpaul

going up through the ceiling below can be easier

Grallert

You could try raising the radiator up an inch. Sometimes this has the effect of raisinf and in turn adding more pitch to the hidden pipes.