I just purchased a new house and it has a hot water circulation system. I am out in the county using propane. I am trying to restrict utility usage and don’t want the pump running constantly. I can set a timer at certain times of the day but all that does is make my water heater heat up cold water for no reason. Purpose of this circuit is to allow me to push a button in the desired room that i want hot water and after a few min or so be able to get it. On the wall next to the switch would have two indicator lights one blue (cold) and red (hot).

Momentary contact with a latching relay and a temp switch to release the latching relay.

Temp Switch would have a sensor at the recirculation pump to sense temp returning to the water heater.

Does everything look ok? or am i missing something

Thanks

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Should look into on demand electric water heaters, they're exremely efficiant for occasional hot water usage.

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Or on-demand gas heaters? - I've just had a new central heating and hot water system fitted, using a Combi boiler. When you turn on the hot tap the Combi boiler senses it (via the water pressure, no wires) and fires up - after a few seconds you get hot water. They aren't new, they have been about for years - although new ones have to be Condensing Combi Boilers, which condense any toxic waste products and empty them down the sewer.

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PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

How about just removing the circulating pump.

 

The circulating pump is very useful...I live where there isn't allot of water and wasting it down the drain isn't very efficient at least I don’t think. It takes quite awhile to get water to the shower without it. (End of the loop) But I also don’t want to run the circulating pump all day either. A cheap circuit would allow me to circulate the water when i need it, but it also has to be idiot proof. (Kids and Wife proof)

 

I have wondered about the effency of hot water circulating pumps in homes. When I was younger, I worked in maintenance at a large dept. store with a hair salon in it, we had circulating pumps to make hot water always avalible for the hair washing sinks. But that was a case where there was considerable demand for hot water 12-14 hours a day - 7 days a week.

In my home, me and the wife are gone all day, and it only takes a few gallons to get hot to the shower on the second floor. So running it all day would be counter productive as heat loss thought the copper pipes would make my gas water heater run more. Running a pump on a timer would be better, but is saving a couple gallons of water a day worth all the extra wiring and effort?

I really like the on demand water heater idea. I'd like to get one when I get a newer house. Its pointless to heat 25-30 gallons of water 24 hours a day.

 

I replaced my old hot water tank with a smaller "fast recovery" tank. It has a high efficiency multi-coil heat exchanger and is well insulated.

It is a good alternative to the "On-demand" combi boilers, it is not instantaneous but does heat-up much faster than a conventional hot water tank and does not suffer from the corrosion caused by directly heating "mains" water.
(It can also be used with combi boilers to improve the hot water flow though.)

Hot water is pumped and controlled by valves to allow heating/hotwater/both

see: http://www.albion-online.co.uk/

 

Some general observations regarding the topic.

In cold climates the water heater and pipes are inside the insulation of the house. Heat lost by the water heater during the heating season contributes to heating the house. It is nice to have that hot water now on a cold morning so let the pump run.

On the other hand during the cooling season it is a double whammy. Maybe better not to run the pump in the summer.

Good pipe insulation should help.

 

I would think the contribution would be very small. Heat lost in the walls of an older house like mine would rise up the wall and into the attic for the most part.

On the flipside, I have some pipes in an exterior wall, and it would be nice to be able to circulate the water in those on the cold nights we have been having as of late. I worry about them freezing!

 

Haven't gone through your circuit yet, so I'll post again, but my initial impression is that it is overly complicated. I'm wondering if you would accept simplifying by using a fixed time delay instead of waiting for a specific temperature to be reached on the return water. For example, if you used one time delay relay you could really simplify this whole thing. Such relays typically allow you to dial up a fixed ON time up to a couple of minutes. If this is enough time to get your farthest tap's hot water up to temperature, it would be simpler indeed.

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RadioRon

 

I was just sitting here reading this and i notice the can of beer i was consuming had a few chunks of ice in it. It occured to me that if this can of beer had a some warm beer circulating inside then the rest of the beer would never had freezed up. And that got me thinking..it got me thinking about getting another can of beer and something about frozen water pipes but i can't remember what ah, umm..beer.

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2.4Gigglehurtz

 

My thinking was colored by how things work with my house.

It looks like what I suggested does not apply to poorly insulated homes. The OP said he had a new home. I wonder if it is newly constructed or just new to him.

3v0

 

I am hip to the option to putting in a time delay relay. They are very reasonable and would simplify the circuit quite a bit.

The House built new in 2001 a custom home with some real nice features. The original owner went cheap on some items that count. But i am working and improving those items as i go along. The house has duel pane windows but for some reason used standard plastic skylights which the house has four of, i will change those out to prevent heat from escaping in the winter and vise versa in the summer.

Heating the house by running the circulating pump wouldn't work too well. The pipes are run in the attic and only would heat the space up there. Which is vented too well at least IMO. Maybe it will work well in the summer..?

Thanks for everyone’s ideas and input

 

Just a quicky,im in the uk and have a fully pumped system and can independantly select water and heat on individual times via the programmer.
What system do you have?
Is your pump mains voltage?ie 230vac(europe) or 120vac?If so you could make life really easy and just buy a plug in digital mains timer,which comes with a plug socket which you can just plug the pump into(just wire a plug on the end of the feed cable to the pump)Then you can set on and off times during the day!!