Water hammer caused by hot water circulator pump sensor valve

[Home CA]

Just wanted to post a note for someone who might run into this in the future.

I have a Watts hot water circulating pump, this guy:
https://www.amazon.com/Watts-500800-Instant-Recirculating-Install/dp/B000E78XHG

The thermocouple/sensor valve is installed at nearly the furthest point on one end of our house, at the master bathroom sink.

In the past few months, we started having worsening water hammer. I've been racking my brains, checking our PRV, the hammer arrestors at the washing machine, even crawling under the house to look at the pipes...

Anyway, turns out the issue was in the sensor. It occurred to me to shut off the water at the master bathroom sink, and test the hammering at other faucets -- with the water shut off, there was no hammering. I removed the sensor from the mix, and the hammering stayed gone. Finally!

I don't recall seeing anyone mention anything like this in regards to hammering, so just wanted to make a note of this in case it might help someone.

 

[Breplum]

Of course removing the "sensor" which is a thermal bridge, defeats the ability of the so-called recirculating pump to do anything.
So, either purchase a new bridge or unplug the pump.

 

[Sponsor]

 

[Jeff H Young]

so replace your part and let us know if its fixed. but you seem to be on to something . I don't see removing s recirc system a fix So lets see it work and not cause hammer