Check valve type, and installation (direction, Horizontal or Vert)

[OldSalt]

I'm having a problem with a check valve on my tankless hot water re-circulation line. It's evidently failing, as I have cold water in my hot water faucets/showers at the end of the run. The valve that is there is a spring-loaded-ball type (versus a swing) and is only a few months old. I've concluded that either the valve is bad, it's the wrong type of valve, or I installed it incorrectly.

Due to space constraints, I installed it vertically, with the intended flow going down, and checked flow going up. I know that swing check valves must be installed horizontally, but understood that the spring loaded type could be installed vertically. Is that correct?

The secondary issue may be water quality. I installed a whole house water filter to screen out small rock chips (i.e. like large particles of sand) in the water, which was clogging the water heater filter weekly. Those chips are still getting through, albeit at a slower rate. I intend to replace the filter with a y-strainer, as soon as Rinnai tells me the size mesh they use in their filter. It's possible that that grit is blocking the check valve as well, although it's on the opposite filtered side of the line.

Thanks for the advice, guys.

 

[WorthFlorida]

Is this something new or just started?
A spring loaded check valve works on its spring, not gravity so it can be installed in any direction. If you have grit in your system, a small piece might have wedge itself in the check valve and it cannot close completely. Allow the water to flow and tap the check valve to try to dislodge any debris or remove it and inspect it if possible.

 

[Sponsor]

 

[OldSalt]

Is this something new or just started?
A spring loaded check valve works on its spring, not gravity so it can be installed in any direction. If you have grit in your system, a small piece might have wedge itself in the check valve and it cannot close completely. Allow the water to flow and tap the check valve to try to dislodge any debris or remove it and inspect it if possible.

Thinking about timeline, the check valve was installed about 8 months ago, when I re-installed the Rinnai RUR98i water heater in the direct, versus cross over installation method. The cold water in the hot water line issue has been occurring for perhaps the past four months. At first, I suspected it was a cold water block, due to a faucet being turned on that failed to activate the system (minimum 1 GPH required, but low flow restricters combined with about 50 PSI main, result below spec water flow rates). After we eliminated that cause, and literally with faucets at the end of the recirculation/hot water line running cold for fifteen minutes, I eventually figured out that a check valve failure was the only likely cause.

I have been tapping on the valve to force it to close, which seems to help. So, as I mentioned, I will work both water quality and the check valve issues, by changing out the filter system to something that actually filters.

By the way, I spoke with a Rinnai technician this morning. He told me that they recommend the spring valve over the swing valve type, and that yes, it should be installed horizontally. I was reading on another site that valves can only be installed with water flow up (and checked flow down), but as you said, if it's spring activated, direction (i.e. gravity) shouldn't be an issue. That's why I was checking on this forum.

The problem occurring quite regularly, now. Tapping the check valve may be the interim solution; seems to work any way.