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AD8BC
Senior Member

309 Posts

Posted - 03/17/2009 :  09:04:30 AM  Show Profile  Reply with Quote
I have been hearing a lot of talk lately about hot water recirculators. It seems like a good idea. In new homes, the recirculator has a dedicated return line to the water heater. However, for retrofit applications, there are models that are installed in the furthest bathroom from the water heater and use the existing cold water line as the return (i.e. pressurizing the hot water into the cold water line which, in theory, returns it back to the water heater).

Cool idea, and I'm considering it... but one question to those of you that have them: Doesn't that tend to heat up the "cold" water, and instead of waiting for hot water, do you now need to wait for cold water?

stusviews
Moderator

USA
10874 Posts

Posted - 03/17/2009 :  4:25:16 PM  Show Profile  Visit stusviews's Homepage  Reply with Quote
Yes, but the wait is quite short. The cold is only slightly tepid. The hot water is hot nearly instantly. We've saved many minutes of water running for a shower in the furthest away bathroom and a few minutes in the kitchen. It's really a pleasure washing your hands immediately instead of waiting until the water is hot.

The original timer allows one-day programming. I have ours connected to a controlled Outletlinc http://www.smarthome.com/2473SWH/OutletLinc-INSTEON-Remote-Control-Outlet-White/p.aspx because it's not needed at night nor when we're at work, but we like keep it on during the weekend and holidays. Too, we can easily turn it off when we are away.

BTW, you should install a module at the end of each plumbing run, not just the one furthest away (unless there is only one end). Our home required two.

You will also need electric power near the water heater.

And here's some good news. Ours has been in use for more than five years. We haven't even looked at it in all that time.

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LeeG
Advanced Member

USA
2223 Posts

Posted - 03/18/2009 :  03:38:32 AM  Show Profile  Reply with Quote
I have had my pump installed for less than a year and am very happy with it. The cross over valve between the hot and cold water line closes off after reaching a certain temperature so the cold water is still essentially cold. As Stu mentioned it sure is nice to have hot water in seconds. My hot water heater is on the opposite end of the house from the master bath so there was always a long wait to get hot water. The pump utilizes about 25 watts of power and has a built in timer if that works for your schedule. Being retired my schedule is so unpredictable I put the pump on an Insteon ApplianceLinc controlled by a KeypadLinc button. I press the KPL button a few minutes ahead of wanting hot water in the master bath and then turn if off when no longer needed. Also works well for getting hot water to the laundry room which is also on the opposite end of the house. Well worth the expense for the convenience of near instant hot water. Plus I feel certain it saves in electricity cost as I am not running replacement cold water into the tank just to get the hot water from one end of the house to the other. If I was paying a water and sewer fee based on water usage that savings alone would probably justify the installation. Being on a well at this house that did not factor into the decision.

Lee G
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AD8BC
Senior Member

309 Posts

Posted - 03/19/2009 :  10:30:09 AM  Show Profile  Reply with Quote
Thanks guys, it gives me something to think about. I have to wait a long time to get water into the kitchen, and a much longer time to get it to the guest bathroom. I'll have no problem dropping a GFCI outlet under the sink in the bathroom to power it... either down the wall from the sink outlet or I think the bedroom behind the sink cabinet has an outlet close enough to tap off of.
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LeeG
Advanced Member

USA
2223 Posts

Posted - 03/19/2009 :  10:55:03 AM  Show Profile  Reply with Quote
My re-circulating pump installed at the water heater on the hot water discharge line. One end of the pump came with a union which screwed directly to the threaded hot water discharge. The cross over valve is mechanical requiring no electrical connection in the master bath.

Lee G
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AD8BC
Senior Member

309 Posts

Posted - 03/19/2009 :  11:08:46 AM  Show Profile  Reply with Quote
Oh. I get it, Lee. The pump runs and when the crossover valve detects the extra pressure it opens into the cold water line, but cuts off at a certain temperature?
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LeeG
Advanced Member

USA
2223 Posts

Posted - 03/19/2009 :  11:49:37 AM  Show Profile  Reply with Quote
Exactly right. The pump is low volume so when the mechanical temperature sensor in the cross over valve closes when it detects hot water at the cross over valve, the pump is not bothered by the closed value. Also the valve closes slowly so there is no chance of a water hammer. You test the cross over value by leaving the cold water supply valve closed, turning on the vanity faucet for cold water only. Initially cold water from the hot water supply line runs. As the water temperature increases, the cross over value slowly closes until hot water completely closes the value. I looked for the paper work that came with the pump as it specs the temperature at which the cross over value closes but my filing system has misplaced the instructions. The cold water at the bath room vanity is a little warmer than cold water for a few seconds but it does not affect cold drinking water in the kitchen.

I think I have seen pumps which install under the vanity itself but that requires a GFCI inside the vanity. This installation was very simple both at the hot water heater where I already had power and at the vanity. The existing hot and cold water supply lines are connected to the cross over valve. New braded water lines (supplied with kit) are connected from the cross over valve to the vanity faucet. All the vanity connections are threaded so no special plumbing skills required.

Lee G
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Jill747
Starting Member

USA
3 Posts

Posted - 06/02/2009 :  8:30:13 PM  Show Profile  Reply with Quote
Hi im a little new here and i would like to share my thoughts on this. Yes, there are heaters nowadays that has automatic controls when the boiling water reaches its certain level and it auto cut the electric connection to save energy.





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Edited by - Jill747 on 06/02/2009 8:30:37 PM
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klundy
Average Member

99 Posts

Posted - 09/20/2009 :  08:42:43 AM  Show Profile  Reply with Quote
I'd be interested to hear what model pump people are using.

Kevin
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LeeG
Advanced Member

USA
2223 Posts

Posted - 10/19/2009 :  09:53:32 AM  Show Profile  Reply with Quote
I use a Grundfos Model UP15-10SU7P hot water circulating pump. It has a mechanical timer built in for those who are on a predictable schedule. My hot water usage is not on a predictable schedule so I use an ApplicanceLinc controlled from a KPL to turn on the pump. To insure I don't forget to turn it off (even though the KPL button LED is a reminder) my EZSrve will turn it off after a predefined interval. The pump draws about what a 25 watt light bulb draws. Very satisfied with the pump.

Lee G
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