Pls help me buy under-sink, POU, electric, tankless water heater...


  #1  
Old 08-24-15, 10:43 AM
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Pls help me buy under-sink, POU, electric, tankless water heater...

...or am I needing a Hot Water Dispenser ?

Better Half's bathroom sink is about 50 feet away from our garage electric HWH. There is a considerable wait (and much weeping and gnashing of teeth with rendering of garments) until hot water arrives at said sink.

There is limited space under the sink. Cabinet is 21 wide x 24 deep x 26 high, but sink bowl and P-trap intrude and I think something like a device 15 inches high x 10 inches deep x 10 inches wide can be installed. Not by me. There is a 120v plug nearby.

Incoming water temp is 70 degrees now and outdoor temp is 78 degrees. When cold weather is here in S. Oregon, incoming water will be 55 degrees or so. Our old AO Smith electric water heater is set for 135 degrees.

BH does not need a LOT of water. Just enough to wash her face. Can't tell if she will use sink stopper. She is not saying. I think not. Is 2 gpm OK?

OK, there are all the parameters. Lastly, does it connect under sink to hot water in line or cold water in....and are we limited to 1500w on a 15A circuit ? Or does electrician go into circuit breaker box in garage and wire two breakers together....or something ?

Many thanks
 
  #2  
Old 08-24-15, 12:07 PM
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You could install a POU heater like this one: Ariston 2.7 gal. 6-Year 1500-W 120-Volt Point-of-Use Mini Electric Water Heater-GL2.5S - The Home Depot

It plugs into a 120 outlet, but if you try to use something else on the circuit, like a hair dryer for example, while the heater is heating, you'll blow the breaker, so it really needs to be on it's own circuit.

A better solution might be a hot water recirculator system. This is a small pump that connects between your hot water line and your cold water line under the sink. When activated, it quickly pumps water from the hot line to the cold line until the hot water arrives, then it shuts off. The easiest way to activate it is with a button. When your wife walks into the bathroom she would press the button. Chances are by the time she actually got ready to use the sink the hot water would be waiting. You can also put it on a timer, or tie it to the light switch instead of a button, but button is easiest. There is still a short delay after pressing the button, but since the time starts as soon as you walk in, it's probably not going to be noticed. And you're not wasting water down the drain while you wait.
 
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Old 08-25-15, 01:15 AM
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Your faucet is limited (by federal law) to a maximum flow rate of 1.5 gallons per minute. That means it takes what seems to be forever and a day to move all the cold water out of the piping from the water heater to the faucet.

If your primary concern is the amount of water that you are wasting down the drain until it becomes hot, the amount is probably a very tiny percentage of your water bill. The cost to operate an additional heater, be it a tank-type or an instantaneous, will likely be significantly more than the cost of the wasted water, not including the capital cost of the heater and its installation.

And yes, I understand the frustration waiting for the hot water to arrive; it takes at least a full 60 seconds, maybe more, for me to get hot water to my kitchen sink and when you are just standing there it seems like an hour.
 
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Old 08-25-15, 05:48 AM
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A watts recirc pump will be easiest.. At the homes stores you can buy for $200

Pump goes on hot side of heater. Set timer thats built into pump for the hours/times your wife may use the sink.




A check valve gets put under the sink you need the hot water at..




These work very well...

Read about it here..

http://media.wattswater.com/PF-IHWRS.pdf
 
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Old 08-25-15, 06:03 AM
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Time for me to install a new outlet near my water heater and install a Watts. Very cool setup.
 
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Old 08-25-15, 03:15 PM
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Now if this pump shuts off when the water hits 98 degrees, would you not end up with quite a bit of water, just under 98 degrees, in your cold supply, if you turned that on when this system was still running?

May not be a problem, but if one wanted cold water it might now be hot ... or perhaps I am misunderstanding how the water flow works.
 
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Old 08-25-15, 03:51 PM
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Now if this pump shuts off when the water hits 98 degrees, would you not end up with quite a bit of water, just under 98 degrees, in your cold supply, if you turned that on when this system was still running?

May not be a problem, but if one wanted cold water it might now be hot ... or perhaps I am misunderstanding how the water flow works.
There is a check valve and upon cold water use you may have warm water temporarily on the cold side. Way less time then waiting for the hot..

.The purpose is HW. And when you turn on the faucet anyway to use it, such as a single lever, you'll have hot instantly and the cold will be as normal when you switch over to cold only because of use. And you will not even know you get warm out the cold.. ( unless you turn on cold only at faucet for first time...)

Hope one could understand this...
 
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Old 08-26-15, 07:28 AM
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Yeah, that is what I thought. I agree that having the hot is the primary issue, but in some cases if one wants the coldest water they can get out of a tap it might go contrary to that. I guess I am thinking of getting a drink of water out of the bathroom or something like that. I would think that a person would want it colder then 97 degrees.

I suppose they could just let it run like they had to do with the hot before the fix.

Anyway, thanks for the idea. It is interesting.
 
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Old 08-29-15, 06:13 AM
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Thanks for your replies. A recirc pump seems to be the answer. I was not aware of this critter....
 
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Old 08-29-15, 06:27 AM
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Let us know the end result and how it works out for you..

Cheers......
 
 

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