How bad is that rumbling pipe?

February 28, 2013 2:15 PM

I got a water softener and when it goes into recharge mode it drains all the water from my water heater. This happens about once a week and it causes the water heater to try and fill. Of course as there is no water being provided this just means it is sucking air. The pulling of air is so violent that it shakes the intake pipes and creates a thundering racket.

I can see the straps that secure the pipes into place have been jerked out of the wall due to the commotion and I am a little worried this might be really bad.

Is this violent shaking going to eventually rip the pipes off the water heater and create a huge mess or are pipes meant to take a decent amount of movement?

Basically is this something I can ignore or should I be getting a plumber ASAP to install something with some give in it?

posted by M Edward to Home & Garden (8 answers total)

I don't know a lot about plumbing, but I do remember the concept of a water hammer from my engineering classes. If this is even remotely what might be happening, you definitely want it checked out and corrected. I keep thinking about the lab equipment my lab partner and I almost blew apart when we accidently created one with the test apperatus we were working with...you don't want that in your home.
posted by chiefthe at 2:31 PM on February 28, 2013

Best answer: If your system has a bypass valve you should use it and turn your softener off. This behavior cannot be right.

At a totally wild guess, I would say your softener was plumbed in backwards, and is pumping water out of your water heater instead of getting it from the outside intake during recharge.

Your water heater is not designed to function w/o being completely full, and could have burned out the upper heating element, if not worse.
posted by jamjam at 2:40 PM on February 28, 2013 [3 favorites]

Best answer: Yes, you need a plumber. There is no way that your water heater should be draining as part of the softner recharge cycle.
posted by HuronBob at 2:41 PM on February 28, 2013 [1 favorite]

Need a plumber, and fairly urgently.
posted by seanmpuckett at 3:17 PM on February 28, 2013

I have a water softener. It does not do anything even remotely close to this during a recharge; what is supposed to happen is that the beads in the softener are rinsed clean of the deposits that they've accumulated, and coated in brine. At no point should water be drained from your hot water tank, nor should there be any thundering racket.

Call a plumber.
posted by ellF at 3:20 PM on February 28, 2013

Response by poster: Yeah, I figured it was bad, thanks. Just needed a kick in the pants to get over the denial.

It doesn't drain completely, the rumbling only happens for about 10 seconds. The softener I have stops providing water during the recharge, this is normal, the manual states that if the computer in the softener senses I am trying to get water during the recharge it will postpone. I think what my issue is the water heater is elevated higher than the softener and I think some water is escaping down because the pressure is not being kept up during the process. Thus the water heater attempts to draw water when it is not being provided and pulls air.
posted by M Edward at 4:01 PM on February 28, 2013

Let us know what the plumber says, please-- but don't use the one who installed your softener, or that company.
posted by jamjam at 4:38 PM on February 28, 2013 [1 favorite]

There's no way in hell water should be draining from the heater. It's downstream of the softener. It sounds like your softener isn't fully diverting the flow when it goes into recharge, causing it to suck from the main system when it discharges. Call a plumber.
posted by Thorzdad at 6:03 AM on March 1, 2013