Here is a little more information about two useful gadgets in our plumbing system.
The previous post lists the rationales behind the hot water routing and makes mention of a hot water circulation pump. Let’s start with that.
Typically, the pump is installed under the fixture that is farthest away from the hot water tank. It is activated with a push button or motion sensor and begins to prime the hot water line. In that process hot water is brought close to each fixture along the hot water line, providing almost instant hot water.
Graphic by: http://www.gothotwater.com/
The most common location for the pump is under a sink, which makes the installation very easy. It is shipped with the needed fittings for a quick retrofit. The package includes two flex lines to connect to the existing hot and cold water lines under the sink.
Our fixture at the end of the hot water branch is the shower, not a sink. That means that I will have to install the pump into the plumbing wall.
We did provide a hot and cold water stub to which we can connect the pump. But I am not ready to trust those stainless steel flex connectors. Not in a plumbing wall where access will be difficult.
Instead I opted for a hard plumbing connection. In other words, I used copper pipe and fittings to connect the pump.
The pump will be plugged into a GFCI outlet in the plumbing wall. Once that outlet is connected, we can pressurize the plumbing system and test-run the pump.
Edit: The on-demand hot water pump is now available at one of the home improvement big box stores (TacoGenie 1/40 HP Hot Water Recirculating Pump with Undersink Kit)
Pressure reducing valve
The pressure reducing valve in the shower riser is the second item I should point out. I gave this nifty gadget some mention in a previous post, but it may be
worthwhile to bring it up again.
The reason for the pressure reducing valve is the shower head, or to be more precise, the desire for a reliable 1.5 gallons per minute (gpm) low-flow shower head.
The one product we found to work really well, in that you get a stream of water that is powerful and does not feel like a trickle, is the Oxygenic® BodySpa® SkinCare™ Shower Head. But it is rated with a 2.5 gpm flow rate – at 80 psi water pressure.
To guarantee a low flow rate of 1.5 gpm for our showers, I’ll have reduce, control and stabilize the water pressure, as can be seen in the graph below.
The graph doesn’t seem to be entirely accurate, nor the dial settings on the pressure reducing valve. We found out when we were field testing what pressure would really get us the desired 1.5 gpm.
Once we had dialed the pressure reducing valve down to 25 psi, the shower head delivered the targeted 1.5 gpm low flow rate.
Should we decide to change the shower head in the future, which may require us to increase the water pressure, we can simply adjust the dial and thereby the pressure on the pressure reducing valve.