Hot Water Recirculation System
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- Опубликовано: 1 май 2023
- Learn how domestic hot water recirculation systems work in residential and commercial buildings. Learn 3 different hot water recirculation systems used in homes.
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Great yet simple straight to the point .. well done video
Thanks for watching.
love this simple and yet very effective explanation....thanks for your channel and vids i just subscribed it.
Awesome, thank you!
Do you tap your return line in on the 1/2 inch line going to the fixture or the main before the tee?
If you're using the bypass valve, you would connect on the fixture branch line. See the manufacturers literature for the correct method of attachment.
How does the under the sink system #2 prevent circulating hot water from coming out when the cold-water valve is opened by the user expecting cold water? Since there is always going to be hot water in the cold line during the time set for recirculation then it would seem that the hot water trapped in that cold line back to the tank would first have to flow out of the spicket before cold water would be felt. What am I missing?
A better choice is a dedicated recirculation line if one is installed. The #2 system ensures instantaneous hot water at the expense of heating up the cold water some. The thinking might be along the lines of 1) It minimizes the waste of water, 2) Most fixtures will require hot water during usage, such as showers, bathtubs, Dishwashers and Clothes Washers. The benefit has to be determined by the user and the usage pattern of the fixtures.
In #2 and #3, you will put heated water into the cold line. Drinking water from the heater is hazardous. You will have to run the cold water for several minutes to flush the hot water out of the system. Basically the same waste as flushing out cold water from your hot line.
We agree that's an important point to consider. Hot water from the tap might contain more minerals or impurities compared to cold water, as hot water can dissolve minerals more easily. If there are concerns about water quality, it's advisable to have the water tested, and definitely use a filtration system for drinking water.
Thanks for saving my time! I wanted to say exactly the same thing. That is not an option for me. I intend to install another tank on the other side of my house and do some replumbing!
Does the bypass valve have to be installed at the sink? Why not the shower or tub?
You want to install the bypass valve at the furthest plumbing fixture so that hot water is available to all the plumbing fixtures along the hot water supply path. It doesn't have to be a sink, but the furthest plumbing fixture requiring hot water.
Provided that the pump is running 24/7, does this system(#2 or #3) make cold pipe to be warm(or hot) all the time? Just wondering if this is worth if it a lot of energy is wasted to heat up both pipe lines at all times.
Methods of control can be added, such as a time clock. This would ensure that the system only runs when the user normally requires hot water.
So Ive designed a dedicated return line in a large home with 2 boilers.. 1 main line for cold water, 1 main line for hot water ( pump feeds 2 boilers, a header of 2 outlets) connects to the home paralleing the cold water line.. distance is about 200 feet of piping ... a seperate return line around the home and there are 2 risers with fitting from further point on each side of the home flow down to a pump room where it meets a hot water recirculating pump with thermostat.. problem we have is that the hot water kinda comes and goes .. like a bit of a pressure imbalance.. water pressure is pretty good for both lines. I shut off the return lines as a mean to test to see if under normal conditions there is balance.. the pressure becomes lower.. whats the best way to diagnose this problem? and is it ok to have 2 pipes opposite side of homes flowing down and connecting to an outside network (underground) dedicated return line? there are also faucets below kitchen etc.. the plumbing Contractor added return lines for almost everything.. I am lost and need some help. Thanks a million
Definitely need eyes on this problem. Can you hire a local engineer to review? It would be great if you had the original design drawings for them to review along with the specifications of the pumps. Remember the longer the piping and the more fittings there are, the greater the pressure drop in the system, which adds additional head to the pumps. Can the pipe and fittings be visually inspected along its full length? We suggest finding someone locally that has an engineering background to review the site and drawings if available. Good luck.
After the upstairs bathroom sink couldn't you use 1/2" pex to return to the water heater? Would the increased velocity of the smaller return be harmful to the pipe?
As long as there is some method to circulate the water when not in use, so that the hot water is readily available for the user based on usage patterns and the normal time of day that the fixtures are used. The 1/2" size shouldn't be a problem as you're just trying to keep a small amount of hot water circulating so that at the time of use you don't waste a lot of water to reach the hot water.
Thanks alot ❤❤
Thank you for watching
I've had my recirculating pump installed under my Rennai instant water heater in our garage and a Bypass valve installed under the sink on far side of our small 1650 ft home. My wife has complained constantly...let me emphasize the word "CONSTANTLY'...No hot water!!! She'll run the sink hot water valve for minutes before hot water.
Question(s): If you turn on cold water while waiting for the recirculation of hot water, does this prevent hot water from recirculation?
If you have to wait before using using cold water how long to wait? Long enough for her to make me an espresso, rub my back, massage my feet...yea this ain't happening either so about how long??? Much thanks for your reply.
Sounds like something isn't connected or set correctly. Has it ever provided hot water on demand as intended? Is there a timer that isn't allowing it to run when you normally use the hot water. The timer should allow you to set the pump to run just before your wife normally uses the hot water at the remote sink. Make sure that the timer is set to circulate hot water before she needs it, that way you don't waste energy. Running of the cold water won't matter at the time of use, as the hot water should be timed to already be waiting for the user.
With a recirculation pump on the heater does an expansion tank on the cold water line cause a problem or could be damaged?
When installing an expansion tank in a hot water recirculation system, it is typically placed on the cold water supply line to the water heater. The tank contains a diaphragm or bladder that separates the water and a cushion of air. As water expands, it compresses the air, allowing for the accommodation of increased volume without causing a significant rise in pressure.
It's important to consult local plumbing codes and the manufacturer's guidelines for both the water heater and the expansion tank to ensure proper installation and compliance with regulations.
@MEPAcademy Thanks for the info. I've got an expansion tank on the cold side and am looking into having a recirculation pump put on the system. I'm concerned that the water recirculation goes to the heater on the cold side and if that could damage the expansion tank?
Method one, would water be recirculating when circulation pump off, would this also cause pressure to drop in the hot line?
The water won't circulate through the return line when the pump is off. Hot water can flow through any fixture when the pump is off, as the city water district provides the pressure required for flow. The pump only runs as required to maintain a certain temperature as set by the home owner, or as dictated by a time clock. Thanks for watching.
Hi dominic in 70 years here in south africa we never heard about a legionella situation in a hot water geyser.
If the ac cooling tower water is not chemically treated then legionella is highly possible.
Very true, water treatment is very important in cooling tower applications.
What is the head feet of option #2 and # 3? I am going about 22 feet to an upstairs bathroom
That is not a long distance, as long as you don't have tons of fittings a small recirculation pump should work fine. Check with your local supplier on the various pumps and their capacity.
In system without dedicated return line. The "not-hot-enough" water is sent to the cold water line eventually into the water heater, if the hot water is not potable, is this setup going to send non-potable water into cold water faucets?
Not sure we understand the question, but you should never mix non-potable water with potable water unless code allowed through an approved back flow preventer.
If you have potable water connected to a non potable system, such as a boiler for makeup water, you'd have a backflow preventer on the potable supply before the boiler. You'd connect the return after the backflow preventer on the supply side.
Correct, any industrial use of a potable water system would have to use an approved back flow prevention device.@@bisurdaddy
No one ever talks about how very loud these constant hot water systems are?
Is the sound coming from a pump, velocity in the pipes, or as water hammer noise?
that is not right, the return line should connect to the hot pipe on the boiler. why put in on the cold line??
So it can go back into the water heater and get reheated. If it went to the hot side of the boiler it would dilute the hot supply of water, which is counterproductive
@bisurdaddy Thanks for the response.
we do it differently. the circulation iz connected to te hot line and circles the hot water in the pipes so as to receive the hot water instantly. never saw it done it your way so i was curious. @@bisurdaddy
@@bisurdaddyso every single fixture's cold like also connected to hot water tank ?
@@bisurdaddyhow you gonna make sure only water which was hot before will go to hot water tank not the regular cold water?
You didn’t mention the most important reason for having a flow&return hot water system, which is to prevent the growth of Legionella bacteria in the warm water pipes.
Great reminder. Thanks.
"What warm water pipes" are you talking about? When someone turns off their hot water faucet does the hot water pipe turn into a warm water pipe? Are you referring to the thermostatic valve under sinks that remain open until 95F water arrives at the sink?
@@utube4greenfuture Legionella will multiply in pipes that are between about 20 and 60 Celcius. Temperatures higher than those will kill the bacteria. In temperatures lower than those then it doesn’t multiply. You must ensure that your pipes aren’t stagnating with warm water in that range. The solution is both technical and procedural. A hot flow and return system which ensures that hot water flows regularly through to the furthest point of the system is the technical part. The procedural part is to run taps regularly…