Corroded brass check valve

[monkeywrench]

House is 4-1/2 years old, and kitchen island was getting intermittent hot water, so I planned to try cleaning the sweated "brass" check valve downline from the recirc pump. When I removed the insulation sleeve, however, I found massive electrolysis corrosion on the outside of the valve body, from one end to the other, as well as around the cap on top (photo attached) . The copper-to-copper sweated joint one inch further downline, and the sweated joint between the brass recirc pump body and copper outlet pipe are both clean and bright. I suspect that the brass material used to make the check valve was not compliant with industry manufacturing standards. Any thoughts on this? Is it possible that the builder used a check valve that was not designed for water?

 

[Jeff Handy]

Your picture comes up blank, on my iPhone.

 

[Jeff Handy]

Meanwhile, the old valve is corroded, so replace it.

If you are not good at soldering, you can use compression fittings or Sharkbite fittings, to splice in a new checkvalve.

 

[monkeywrench]

Thanks for your input, Jeff. Yeah, I got that it would have to be replaced (you should see the photo!), although I had not thought of compression fittings. I have had some successful experience at sweating copper pipe, but I have started a negotiation with the builder to supply the install labor if I purchase a new check valve.

I would still like to hear from anyone who has experienced this type of brass corrosion in such a short time, though, while all of the copper-to-copper joints in the same line are clean and bright. I'm wondering if I should beware of certain check valve brands.

 

[Jeff Handy]

Repost your pic, I think it has a problem.

 

[monkeywrench]

Re-posted as JPEG (original was PDF), so you should be able to view it now.

 

[Jeff Handy]

Yes I can see it now.
Looks more like it has been leaking for years.

 

[Diehard]

Yes...it does look like it's from a leak.

In any case, can that top plug be removed, allowing you to inspect the actual check valve function? Wire brush the plug joint, then lubricate with something like liquid wrench. Then tap it with something metal a few times, like a screw driver or small wrench to set up some vibration. Let it penetrate awhile if no go on the first try.

 

[monkeywrench]

Here is an update on what I have discovered. The builder's tech opened the check valve top plug (turned out to be easy-peasy), and I've attached a photo of the interior of the check valve. As you can see, it has accumulated massive mineral deposits from the local hard water, even though we have a high-end, whole-house (i.e., hot AND cold) softener, and only use potassium chloride. I also had the softener system checked out, and found that it was doing its job.

This is a new recirculating design for this builder, and it's pretty obvious that it's a dud, under our circumstances. I've also attached a rough diagram of the recirculating system, illustrating the problem area where the recirc return is plumbed to the cold water inlet. When the check valve sticks open, cold water is drawn backward through the pump whenever a hot water faucet is turned on. I would like to use the same Grundfos Comfort 10-16 pump, but perhaps plumb the output to the lower flush valve of the water heater? Any other suggestions for reconnecting this pump in a configuration that does not require a check valve?

 

[Diehard]

The diagram you show is the typical arrangement for that system. Either brought back to the CW inlet OR alternately to a tee connection on the water heater drain line(as you suggested).
It may be less apt to accumulate whatever that buildup is, when connected to the tank drain instead. Who knows?

You had originally suggested that perhaps the check valve was not designed for water? That's kind of doubtful. Look on the side of the check valve for a designation"WOG". That stands for Water-Oil-Gas applications.

Regardless, I wonder if a PVC Swing Check Valve would help avoid that build up???

Just out of curiosity...
What controls your pump operation?
Strictly manual?
Timer?
Aquastat?
Combination of above?

EDIT: I would be inclined to reroute that return line to the tank drain. In doing so, add a ball valve to allow future isolation of pump and/or loop. Periodically check interior of new or cleaned up check valve to see how frequently the build up may occur. And if need be, clean it out before it stops functioning.
Maybe add 2 ball valves to allow easy isolation and cleaning(if need be) without draining any of the system.

 

[SHEPLMBR]

Is that really a hard scale build up? It almost looks slimey.

 

[Diehard]

Is that really a hard scale build up? It almost looks slimey.

Yes... it looks like a lot of both.

But enough to hold the flapper open apparently.

 

[monkeywrench]

Well, it's definitely a mineral buildup - it had to be scraped out; but it was not hard like rock. I would call it a soft scale buildup. I should have taken a sample for analysis when the tech had it open. However, it was not something that could be completely removed, so a little (or a lot) of it remained in the valve, line or HW tank. It's just a gravity check valve, so it doesn't take much to keep it from closing, or to clog the seal.

Yeah, my question about the check valve not being for water was during my panic mode (stuck without HW over the holidays). When I thought about it, I realized how ridiculous it sounded.

Pump control can be either by thermostat, continuous running or "smart" sensing. I usually use the thermostatic control, but when the check valve jams open, cold water can be forced back through the pump when it has stopped and a HW faucet is opened. Lately, I've just had it in continuous operating mode. So-called smart sensing is a non-starter for us, since our HW usage schedule is not regular enough to learn.

I agree with Diehard's EDIT comments in reply #10. Sounds like the best solution. At least I won't have to check and clean the valve 8 ft. in the air!​