Hot water recirculation questioins

Since this involves metal plumbing I figger it's probably OK to post my questions. Because of the way my house is plumbed it takes a long
time for the water to get hot at a few fixtures. I could put little water heaters at these fixtures but that would require running power to the fixtures. Though this could be done it wouldn't be easy. I looked at two types of recirculating systems and both are lacking. One relys on a thermostatic valve opening up between the hot and cold pipes when the hot side cools enough. For the system to work a pump must be operating , to keep the hot side at a higher pressure. The other sustem I looked at requires running wires from each fixture. The wires power a solenoid valve and provide a signal to turn on a pump. But that would require running wire which as already stated isn't that easy. I'm wondering if maybe a check valve and a differential switch could be used to turn on the pump when the thermostatic valve opens. The valve doesn't require power and each fixture can have its own valve. Or just one valve can be installed at the furthest fixture. Advice anyone? Thanks, Eric
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On Mon, 05 Jun 2017 09:06:00 -0700, snipped-for-privacy@whidbey.com wrote:

I vote for the spot heaters. If you do recirculation, the pipes better be short and/or well insulated. Otherwise they'll become radiators, increasing your water heating costs and your air conditioning costs if applicable. How much, depends. But a friend whose pipes were buried in his concrete slab managed to increase his bills by $100 a month when he added recirculation.
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On 6/5/2017 11:11 AM, Neighborhood number 3 wrote:

Recirc means reheat all of the time. Return of cool water to keep hot at a tap costs money. I know of a couple that disabled theirs due to cost. They could afford it but it was electric (pump) and gas or electric to heat.
It is best to have a demand unit that boosts the temp to the need of the area then turns off. So the pool area has hot water but doesn't cost in the off seasons.
Martin
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In my laundry room the flow though the washing machine shutoff valves is much greater than the flow through the faucets on the bathroom sink the previous owner installed. If one of your distant fixtures is in a utility room maybe you could install larger faucets to rapidly purge the pipe.
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On Mon, 5 Jun 2017 12:44:55 -0400, "Jim Wilkins"

One way or the other, Eric, you'll either have to run a wire or additional piping. Neither is cheap, quick, or fun.
Hmm, thinking about it, you could put a 1/2" dump valve in the end of the feed to the hot water supply line to the sink and dump it in the drain pipe -after- the P-trap. That would expedite the travel of the water to the supply pipe at the sink, but it wouldn't require major plumbing changes in the wall/under the house. It would be a real PITA to plumb, but it might help.
Alternatively, run smaller pipe or higher pressure and insulate well. Something I'll do in the future, if/when any major plumbing problems come up, is to switch to PEX and insulate it all the way from the pump house to each tap. Instead of spending $300 to do a small job, I'll break out the cob-webby old credit card and do the entire job once and forever. Many of you know how nasty 'old' pipe is to work with. You attempt to unthread a leaky pipe and it breaks the next pipe on the other side of the fitting. And they're all constricted internally from age, anyway.
The galv pipe was installed in the early '60s. Nobody could have been more surprised than me when the water main to the house froze solid 5 or 6 years ago, -without- bursting or leaking. I put a Patton milk- house heater under the house for 5 hours and the toilet started filling several hours later (after bringing in the heater) with no ill effects. I was thrilled. http://tinyurl.com/ybo65vqo
To get hot water to my bathroom faucet, I run the hot in the tub first, then open the faucet. Most often, since it takes a minute to get hot, I just avoid using the bathroom sink hot faucet. It takes 20 seconds in the kitchen.
I've thought about the continuous hot water and can imagine how much it costs (both materially and electrically) annually for that little convenience. You either waste water (run 'til hot) or electricity (looped hot water.) Plumbed continuous is probably considerably cheaper than a POU water heater for each faucet in a home. Solar pumped systems would probably be the cheapest when considering lifetime costs.
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On Monday, June 5, 2017 at 12:00:23 PM UTC-4, snipped-for-privacy@whidbey.com wrote:

I have thought about this, but have never gotten around to doing anything.
My thought is to have a switch in each upstairs bathroom that would run the recirculate pump They would be wire the same as a three way switch so the pump could be turned on and off from either bathroom.
Thus would not be a automatic set up. If one was about to use hot water , one would turn on the pump for a minute or so before using the hot water.
Dan
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On Mon, 5 Jun 2017 11:27:25 -0700 (PDT), " snipped-for-privacy@krl.org"

Your solution would reqiure running wires, which I don't want to do. Eric
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You could use a wireless switch at the remote location, with the pump on a timer at the water heater.
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On Mon, 5 Jun 2017 16:14:19 -0400

Also, you could use a low voltage control (~24vac), similar to a door bell. Small wire, easy to fish here and there and a lot less code requirements...
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wrote:

If fishing the wiring isn't an issue that's easier to set up. Multiple switches could be paralleled on one wire pair to trigger a time delay relay so you don't need a forgettable Off switch. The check valve connecting hot to cold could be a spring-loaded pressure relief set low, so the line pressure drop from running cold water doesn't draw in hot. I've had good luck winding replacement low-tension springs for failed hose nozzles from stainless TIG rod. -jsw
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Use a timer, not a switch.
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On 6/5/2017 11:06 AM, snipped-for-privacy@whidbey.com wrote:

I have that long-time-til-hot problem at the dishwasher/kitchen sink . Probably aggravated by me using all 3/4 PVC right up to where the service comes thru the floor . In my case though , it's going to be relatively easy (we're still constructing) to add an instant-hot water heater under the sink . Just gotta get the unit and see what wire I need . I might get lucky and be able to use the 12 ga I have on hand .
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