Recirc Pump, Momentary Switch, Hot Water

I am a full time, only when the need arises, do it yourselfer. My mother's home has the hot water tank at one end of the house, the two bathrooms at the other end. I'm not too jazzed with a pump at the tank a thermal switch and bypass valves at the sinks. I don't like the idea of paying to keep that run of pipe hot all the time. I'd rather install a pump at the sink, a momentary switch that would run it for a (adjustable/preset) length of time, drawing on the hot and pushing back the cold side. If anyone can share some advice, I need some help on the hardware side. Type of pump, and how to run it for a preset length of time. Thank you for any advice.

Check out www.tacohvac.com Their D'Mand system will do that. There are others as well, but that one comes prepackaged with what you need. They offer an optional wireless remote if you want to operate it in another location as well as the "local" pump location, or you can hardwire addtional switches like a doorbell.

The cost of operating the pump in a recirculating system is very minimal. You can get one that operates off a timer so that it would only operate during the period of use. The advantage is you have instant hot water during the time the pump is running.

Engineering Solution:
Get a bronze circulator about 3-5 GPM. Install the circulator in a cross connection from the hot to cold side, with a check valve. Between the cross connection tee and the hot water faucet, install a flow switch (about 0.3 GPM) and a temperature switch.

Hook up the flow switch and the temperature switch to a relay to operate the pump under the following logic conditions:

When the FLOW IS ON AND the TEMP IS LOW, operate the pump. As soon as hot water arrives OR the flow stops, the pump is turned off so you don't fill the cold water line with hot water.

Hot water should arrive in about 10 seconds, depending on pump capacity, pipe size, and distance.

That's basically how the Taco system works...but is has everything you need in one kit. Maybe less expensive to do it yourself. Mine (Redy-Temp) has a thermostat. You set the temp of the water, it runs when it needs to bring it up to that temp and then shuts off. Also has a timer on it so it only runs when I need/want it. I've got it on a digital 7-day timer so weekend and day programs are different.

pump

Without the thermal valve at the sink to stop the flow when the water going into the cold system becomes warm, you will have no control over how much hot water enters the cold piping. You can install something like the Grundfos Comfort System and then control the pump anyway you wish to. Timer, X-10 wireless switch, flow switch, or whatever.

Thank you to all, I feel i now know enough to be dangerous!