Instant Hot Water

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junquecol

Bruce
User
Do you have a sink, or shower that takes forever to get hot water? Watts makes a recirculating hot water system that uses existing lines. Basically it's a pump with timer mounted at water heater, and a thermostatically controlled bypass valve that is located at furtherest faucet set from water heater. When pump cuts on, valve allows cold water (from hot water pipe) to return using cold water line. When valve senses hot water it closes, shutting off flow of hot water. Both BORGS carry system, which retails for less than $200. Hardest part of the installation is getting 110 to run pump at water heater. This system could also be used to prevent pipes from freezing
 

Gotcha6

Dennis
Corporate Member
We use similar systems in medical facilities where doctors don't want to wait 30-45 seconds for hot water to wash their hands. They can be put on a timer as well & are effective, but for a long run a regular instant hot water heater is better if it serves just a lavatory or sink.
Another option some people are using is manifolding the hot water at the heater so each fixture has an individual 1/2" supply line directly to it instead of a 3/4" line reduced near the fixture. This eliminates heating an entire 3/4" pipe and its water before getting it to the fixture.
 

Tarhead

Mark
Corporate Member
I like the type with a sensor that knows when you walk into the bathroom and turns on the recirc. pump for a pre-set time to get the hot water to the faucet or zone. Saves lots of water.
 

junquecol

Bruce
User
We use similar systems in medical facilities where doctors don't want to wait 30-45 seconds for hot water to wash their hands. They can be put on a timer as well & are effective, but for a long run a regular instant hot water heater is better if it serves just a lavatory or sink.
Another option some people are using is manifolding the hot water at the heater so each fixture has an individual 1/2" supply line directly to it instead of a 3/4" line reduced near the fixture. This eliminates heating an entire 3/4" pipe and its water before getting it to the fixture.
Recirculating hot water is standard in hotels / motels. But you have two hots, one for supply, and the other for return. What is unique about this system, is it uses EXISTING water lines. Because most of us are creatures of habit, meaning we get up the same time each day, it would be easy to set timer to come on same time as alarm clock goes off. By setting timer on pump for constant run, and then adding a digital timer, you set times based on the day of the week.
 

Tarhead

Mark
Corporate Member
Bruce,
So this is pumping hot water from your hot water line into your cold water line? What happens when you brush your teeth? Does hot water come out of the cold faucet? Doesn't sound very efficient to me but I'm not the sharpest pencil in the bookbag tonight.
 

froglips

New User
Jim Campbell
Being an armchair plumber, I have followed this post with great interest.

As I recall, another benefit of the pumps is reduced wasted water while one waits on that hot water.

Jim
 

Gotcha6

Dennis
Corporate Member
Bruce,
So this is pumping hot water from your hot water line into your cold water line? What happens when you brush your teeth? Does hot water come out of the cold faucet? Doesn't sound very efficient to me but I'm not the sharpest pencil in the bookbag tonight.
The pump return line usually discharges the water into the water heater inlet line so it is reheated.
 
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timf67

New User
Tim
Bruce,
So this is pumping hot water from your hot water line into your cold water line? What happens when you brush your teeth? Does hot water come out of the cold faucet? Doesn't sound very efficient to me but I'm not the sharpest pencil in the bookbag tonight.
I actually just had one (a grundfos) installed as part of our addition since the laundry room was very far from the HWH and we wanted a load of hots to actually get some hot water... :wink_smil

Anyway, the pump is very small (about the size of a coffee mug) and can be set to run full time or on a timer. The return valve is thermostatic which means that it only opens when the hot water temperature drops below a certain point. The valve then opens and lets the now cool hot water flow into the cold water line. Since the system is a closed loop, the cool hot water pushes the now "extra" water in the cold line into the HWH. The setting on the valve is low enough so that the cold water is lukewarm when you turn it on (basically the temperature of the cold water that you get during the summer).

I like the fact that you save water, but you do use more electricity for the pump and to heat the now circulating hot water.
 

Tarhead

Mark
Corporate Member
Tim/Anybody else that has these,
I looked just now on their website and it makes sense. My concern is that where I need one -our remote master bath...farthest point in the house from the hot water tank- it would push hot water into the cold line and I would have to wait for the water to get cold when I need cold water. This would waste water waiting for it to cool off and waste energy versus installing a loop back to the hotwater tank from the location. It would cost a lot to put a return loop line in for the traditional recirc pump systems and I have avoided doing this so far. This type may work for me, just want to cover my bases.
Also...Single handle faucets and anti-scald valve issues? Saw some negative feedback on Amazon related to this. Any thoughts related to this as we have both in the bathroom.
Thanks!
 

timf67

New User
Tim
The pump is 1/25th of a hp, it is not moving much water, so the cold water side doesn't get hot at all IMO. I have not had to wait for the water to get cold - especially right now :eek:. The thermal valve works by bypassing the faucet where it is installed. A traditional single handle faucet (not thermostatic or anti-scald) would not have issues. A thermostatic valve might have problems since the water on both sides of the valve will be close to the same temp, but you have the same situation right now when you turn it on after the water has sat still in the line for a while. I would think that the benefits would overcome any negatives.
 

junquecol

Bruce
User
Some anti-scald valves require a "seasonal adjustment." Last week, I had to go to a job that had anti-scald valve. Hot water everywhere, except shower. Adjusted valve = happy home owner.
 

petebucy4638

Pete
Senior User
Bruce,
So this is pumping hot water from your hot water line into your cold water line? What happens when you brush your teeth? Does hot water come out of the cold faucet? Doesn't sound very efficient to me but I'm not the sharpest pencil in the bookbag tonight.
I have used recirculating hot water systems in the homes that I build for many years. To do it right you need to plumb the hot water line with a return line so that it can recirculate the hot water back to the water heater.

The system that was described here requires that you run the hot water out of the cold water line before you get cold water. It can work ok for faucets that aren't used for drinking water, brushing your teeth, etc. An instant-hot water heater at the faucet would be a preferred option, in my opinion.

Pete
 

petebucy4638

Pete
Senior User
I actually just had one (a grundfos) installed as part of our addition since the laundry room was very far from the HWH and we wanted a load of hots to actually get some hot water... :wink_smil

Anyway, the pump is very small (about the size of a coffee mug) and can be set to run full time or on a timer. The return valve is thermostatic which means that it only opens when the hot water temperature drops below a certain point. The valve then opens and lets the now cool hot water flow into the cold water line. Since the system is a closed loop, the cool hot water pushes the now "extra" water in the cold line into the HWH. The setting on the valve is low enough so that the cold water is lukewarm when you turn it on (basically the temperature of the cold water that you get during the summer).

I like the fact that you save water, but you do use more electricity for the pump and to heat the now circulating hot water.
One of the issues with this system is that drinking water produced by a hot water tank is not a great idea. Hot water tanks precipitate heavy metals and other contaminants out of the water supply and concentrate them in the tank. By using the cold water line as the hot water recirculating line, you will be consuming water that passes through the hot water tank. If all you are doing is rinsing you mouth out with it, it's not a problem. But drinking it is not something that I would recommend.
http://everything2.com/title/Never+drink+or+cook+with+hot+tap+water

http://www.bookofjoe.com/2008/02/behindthemeds-1.html

Pete
 

Gotcha6

Dennis
Corporate Member
I have used recirculating hot water systems in the homes that I build for many years. To do it right you need to plumb the hot water line with a return line so that it can recirculate the hot water back to the water heater.

The system that was described here requires that you run the hot water out of the cold water line before you get cold water. It can work ok for faucets that aren't used for drinking water, brushing your teeth, etc. An instant-hot water heater at the faucet would be a preferred option, in my opinion.

Pete
+1
 

timf67

New User
Tim
One of the issues with this system is that drinking water produced by a hot water tank is not a great idea. Hot water tanks precipitate heavy metals and other contaminants out of the water supply and concentrate them in the tank. By using the cold water line as the hot water recirculating line, you will be consuming water that passes through the hot water tank. If all you are doing is rinsing you mouth out with it, it's not a problem. But drinking it is not something that I would recommend.
http://everything2.com/title/Never+drink+or+cook+with+hot+tap+water

http://www.bookofjoe.com/2008/02/behindthemeds-1.html

Pete
Let's not propagate misinformation here. Hot water tanks do not "precipitate heavy metals and other contaminans out of the water supply and concentrate them in the tank." If hot water heaters were boiling the water and producing steam I might agree, but you can't concentrate contaminants if you don't boil or at least evaporate some of the water. Having worked in the water and wastewater treatment arena for 6 years, I can say that the cold and hot water in your house are not significantly different - especially if you are regularly using both of them. Notice that I did not say that they are both healthy... I filter all of the water that I drink and cook with.
 

Trent Mason

New User
Trent Mason
Wow, this is some great information. Seems like everywhere I've ever lived I've always had to wait 30 seconds for hot water at almost any faucet. :BangHead::BangHead::BangHead:
 

Tarhead

Mark
Corporate Member
We're waiting about a minute with both faucets running to get hot water in our master bathroom sinks and longer for the shower so this is why this has tweaked my interest....especially if it means we don't have to run a line back to the hotwater tank. I will need to install a 110v outlet under the sink before this will be a reality.
 

Gofor

Mark
Corporate Member
As for the heavy metals, on of the reasons for that thought is because of the amount of lead in solder and the amount of copper piping that used to be used. Hot water will leach lead out of a soldered fitting faster than cold water. The amount is minimal, but lead absorption is cumulative, so over a period of time, the amount could make a difference. With few homes still using sweated/joint copper pipes to any amount, it is rapidly becoming a non-issue.

That said, What I would like to install is a return line from my master bath (about 70 line-feet away from the water heater) with a pump I could manually switch on to recirculate the hot to that room when needed. If it had an auto-off timer (say, set at whatever time it takes for about 2 gals of water to be recirculated), that would be even better. It would only be used about 3 to 4 times a day, so constant recirculating would be a waste.

Go
 

junquecol

Bruce
User
We're waiting about a minute with both faucets running to get hot water in our master bathroom sinks and longer for the shower so this is why this has tweaked my interest....especially if it means we don't have to run a line back to the hotwater tank. I will need to install a 110v outlet under the sink before this will be a reality.
With the outlet under the sink, I assume you are adding a 110V heater. The pump on this system is located at the water heater. Thermo. valve under sink requires no electricity.
 
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