Good day!
After more than 20 years, I have recently started noticing a short, low-pitched noise occurring whenever cold water is drawn somewhere in the house. For example, when the washing machine starts running, when flushing the toilet and the cistern is refilled, or simply when quickly opening a tap.
At first, I suspected anything related to water flowing through the basement, such as the utility company’s valves, at least one of which contains a spring, and also the backwash filter, which also includes a spring. It must be something that can start vibrating. If I heard and felt it correctly, the noise does not come from a specific point but rather diffuses from a section of pipe. Such vibrations tend to spread through the house and can then sound much louder and stronger far from their origin than right at the source.
Now I am wondering: Could it be that there is a buildup of limescale somewhere in the pipe system that partially blocks the pipe, causing vibrations when the water flow begins? I mean: in Berlin, everything calcifies if it is not regularly descaled, so why should a fresh water pipe system be any different?
If we assume this is the case: how could something like this be eliminated? If something is vibrating somewhere, the next step would be that something breaks eventually. Under no circumstances do I want a burst pressurized water pipe in my basement, even though such a failure would be detected quickly by sensors.
There is a drain screw in the service room where I could empty the system. If the valve is closed again afterward, it might be possible to introduce an acid through an upper-angle valve on the cold water side. I remember something like "use acetic acid for warm descaling, citric acid for cold descaling." If the appropriate solution is left in the system for a few hours, all the deposits should supposedly flow out thinly at the drain valve afterward, right?
Or are my assumptions going completely in the wrong direction?
Matthias
After more than 20 years, I have recently started noticing a short, low-pitched noise occurring whenever cold water is drawn somewhere in the house. For example, when the washing machine starts running, when flushing the toilet and the cistern is refilled, or simply when quickly opening a tap.
At first, I suspected anything related to water flowing through the basement, such as the utility company’s valves, at least one of which contains a spring, and also the backwash filter, which also includes a spring. It must be something that can start vibrating. If I heard and felt it correctly, the noise does not come from a specific point but rather diffuses from a section of pipe. Such vibrations tend to spread through the house and can then sound much louder and stronger far from their origin than right at the source.
Now I am wondering: Could it be that there is a buildup of limescale somewhere in the pipe system that partially blocks the pipe, causing vibrations when the water flow begins? I mean: in Berlin, everything calcifies if it is not regularly descaled, so why should a fresh water pipe system be any different?
If we assume this is the case: how could something like this be eliminated? If something is vibrating somewhere, the next step would be that something breaks eventually. Under no circumstances do I want a burst pressurized water pipe in my basement, even though such a failure would be detected quickly by sensors.
There is a drain screw in the service room where I could empty the system. If the valve is closed again afterward, it might be possible to introduce an acid through an upper-angle valve on the cold water side. I remember something like "use acetic acid for warm descaling, citric acid for cold descaling." If the appropriate solution is left in the system for a few hours, all the deposits should supposedly flow out thinly at the drain valve afterward, right?
Or are my assumptions going completely in the wrong direction?
Matthias
Descaling with vinegar is recommended for hot water systems. For cold water descaling, citric acid should be used. You can leave it in the system overnight and then drain and flush everything out in the morning.
To clarify for everyone: I suspect the problem area is in a pipe section below the basement ceiling—so higher than the outlets in the basement, but lower than those on the ground floor. I have a drain screw right at the main shut-off valve, and I can also empty the boiler at the base of the heating system.
My main concern is the cold water side, since the noise only occurs there. However, it doesn’t hurt to descale the coil inside the boiler at the same time, since I will be draining everything anyway. The only issue is, I’m not sure how much water it holds. The whole system is interconnected, which is why I recently had difficulty getting much solution into the system, because the connection to the shower on the upper floor communicates with the air vent positioned at the highest point. For this reason, I plan to ignore that part of the system this time.
There should be about 200 liters (55 gallons) of water inside the tank, right?
Unfortunately, it’s not possible to shut off the cold water supply line to the boiler. This means I can never be certain how much water is actually contained in the pipes, which might prevent the citric acid solution from flowing into the relevant section from above.
To clarify for everyone: I suspect the problem area is in a pipe section below the basement ceiling—so higher than the outlets in the basement, but lower than those on the ground floor. I have a drain screw right at the main shut-off valve, and I can also empty the boiler at the base of the heating system.
My main concern is the cold water side, since the noise only occurs there. However, it doesn’t hurt to descale the coil inside the boiler at the same time, since I will be draining everything anyway. The only issue is, I’m not sure how much water it holds. The whole system is interconnected, which is why I recently had difficulty getting much solution into the system, because the connection to the shower on the upper floor communicates with the air vent positioned at the highest point. For this reason, I plan to ignore that part of the system this time.
There should be about 200 liters (55 gallons) of water inside the tank, right?
Unfortunately, it’s not possible to shut off the cold water supply line to the boiler. This means I can never be certain how much water is actually contained in the pipes, which might prevent the citric acid solution from flowing into the relevant section from above.
Completion report:
The backwash filter had to be completely replaced because it was leaking and, after such a long time, parts were no longer available. Apparently, the pressure reducer inside the old backwash filter was faulty, likely clogged by limescale, which caused the noise. Since the new backwash filter was installed, the noise has disappeared.
Interestingly, and typical for resonance issues, I would have acoustically and by touch identified the source of the problem somewhere else entirely.
However, my treatment with citric acid was not in vain, as the leaking only started afterward, and without the leak I would not have had the backwash filter replaced.
The filter is supposed to be backflushed only every six months. Is that sufficient or should it be done more often?
Matthias thanks everyone involved!
The backwash filter had to be completely replaced because it was leaking and, after such a long time, parts were no longer available. Apparently, the pressure reducer inside the old backwash filter was faulty, likely clogged by limescale, which caused the noise. Since the new backwash filter was installed, the noise has disappeared.
Interestingly, and typical for resonance issues, I would have acoustically and by touch identified the source of the problem somewhere else entirely.
However, my treatment with citric acid was not in vain, as the leaking only started afterward, and without the leak I would not have had the backwash filter replaced.
The filter is supposed to be backflushed only every six months. Is that sufficient or should it be done more often?
Matthias thanks everyone involved!