# Recirculating hot water for instant hot



## K2 (Jul 8, 2005)

When we were doing new homes we were putting in hot water recirc pumps to get the instant hot water at the faucets. When I'd go back to these homes months later, for on reason or another, I would find the pumps unplugged and the valve shut off. If I asked the home owner about he would say the water never was more than luke warm with the pump on. They never really asked us to fix it. So when I did my own home I hired a different plumber who said the other guys didn't do it right and he would install a recirc system that would work. When the house was done the water was luke warm. I unplugged the pump and shut off the valve. That was ten years ago and I really havn't thought about it much. Seems to be alot of good answers on this forum and it would be nice to have instant hot water. Basically the hot water pipe loops around to all the faucets then back to the mech room with a check valve, pump, and then a tee into the cold water supply at the water heater. Any ideas?


----------



## Teetorbilt (Feb 12, 2004)

For the cost, I'll continue to wait for my hot water, all of a minute or less. Turn it on before you start undressing, by the time that you are done, hot water should be there. If you are in a hurry, turn on the hot water only.
If non of the above work, go to the archives (very early). I believe that I posted a fellow fluid engineers booboo.


----------



## plumguy (May 29, 2005)

I normally install my recirc lines by use of gravity(no pump).For this to work the heater has to be lower than the fixtures, if it is a slab then a pump would be needed. What happens is hot water is lighter and will naturally rise and cool water water will fall causing a flow. This flow is very slow(about .5gal/pm), but constant and very effective! If you don't like it's performance then you can always install a pump.

Remove the the drain at the bottom of the heater and install a brass tee and reinstall the drain. Remove you're line from the cold water and pipe to the tee and install a new check valve (flapper type) on the horizontal.

I'm not a big fan of piping them into the cold side. However, if you're trying to salvage you're existing set-up then I would start with a new check valve and make sure the existing one is not spring loaded. Make sure the pump and check are inline properly.


----------



## K2 (Jul 8, 2005)

Yes, I like the idea of going into the bottom of the tank and I'm going to try gravity. Probably won't get around to it until winter. I'm curious about the flapper check valve. I've never seen one and was curious to the advantage. I use check valves on well pumps and some other applications and have only used the spring loaded ones. Thanks for the help. RT.<P>
Teetor, we heat with steam 9 months of the year so one more hot pipe running around the house would probably not cost too much. I would like to read your post and looked back a few pages. Is there an easy way to find old posts? Thanks, RT.


----------



## plumguy (May 29, 2005)

On a gravity loop there is not enough flow or pressure to open a spring loaded check.Flapper type check has a hinged brass door and come sweat or ips(threads). Flapper type are used on sump pumps on the verical and you can even get them in plastic(not for your'e application).Very common suprised you never seen one, check them out at www.wattsreg.com go to parrts then check valves for water and steam it is the cvs model at the top of the page.


----------



## 747 (Jan 21, 2005)

I seen rich T on ask this old house install one of those. He said you have to install at the farthest point from hot water heater in this application under vanity in bathroom. They you plug it in and every once in a while it recirculates the system. I'm bored so I will investigate and find manf. he used if its posted.


----------



## 747 (Jan 21, 2005)

Season 3 episode 308 Richard installs a hotwater recirculator for a homeowner tired of waiting for hotwater in her bathroom....Where to find it.....www.taco-hvac.com.


----------



## plumguy (May 29, 2005)

747, you are correct about those pumps and there are a few manufacturers(Grundfos,Taco,Redytemp,etc.)of those units. Those are great if you don't have a recirculation line already installed. The downside is you need to have an electrical outlet installed under you're sink.Actually, Grundfos has a system called "Comfortzone" that has a control valve at the sink and the pump goes on the heater where it is easier to install an outlet and you can install more than one control valve at different sinks(pretty neat!!). The code here is if a fixture is more than 100'(overall pipe length) away from the hot water source then one must be installed.


By the way, Rich Trethewey is a nice guy and does a great job for the industry.He is local around here I see him once in a while. Thanks.


----------



## Teetorbilt (Feb 12, 2004)

Remember that while all of this hot water is circulating, it is constantly losing BTU's and somebody is going to pay for that. Insulating piping is fairly new and older/cheaper homes could have significant heat loss. Extra heat within the walls could have other implications as well, such as mold development and structural stresses.


----------



## mdshunk (Mar 13, 2005)

"Two pipe hot water" is pretty common for the domestic hot water in taller bulidings and apartment buildings with central domestic hot water heating. I've done work in buldings with 50 year old plumbing that had the hot water pipework arranged in this manner. It's only been in recent years that the new homes and retrofits in homes have been popular. 

In my humble opinion, the two pipe method would be the one to use in new construction, since you won't have that splash of hot water from the cold faucet that you get with the Grundfos/Taco type of system.


----------



## K2 (Jul 8, 2005)

Teetorbilt said:


> Remember that while all of this hot water is circulating, it is constantly losing BTU's and somebody is going to pay for that. Insulating piping is fairly new and older/cheaper homes could have significant heat loss. Extra heat within the walls could have other implications as well, such as mold development and structural stresses.


I know your the engineer but in my house the btu is not lost until it goes beyond the outside walls, (Sept thru May). The efficency of producing the btu is always at question. My Mom lives in florida and I've built in the Carolina's and N.J. It is my opinion that climate makes a big difference in the way a person might do things. I've never had AC in my house or ever felt the need to consider it. Oops I said i would try not to get off thread. RT. <P>
"So much to learn and so little time"


----------



## K2 (Jul 8, 2005)

mdshunk said:


> "Two pipe hot water" is pretty common for the domestic hot water in taller bulidings and apartment buildings with central domestic hot water heating. I've done work in buldings with 50 year old plumbing that had the hot water pipework arranged in this manner. It's only been in recent years that the new homes and retrofits in homes have been popular.
> 
> I enjoy your posts over in the electrical section. I hope that stuff on the 3 phase motors isn't going to be on my journeyman's test but it makes me want to start some classes. Or I'll just keep reading your posts. > Lost me on the 2 pipe hot water. Did I miss something in the thread or is that something different? I believe what i started the thread with was one pipe? > One more quick one on the Rebs burning buildings in your area, (must be York, Harrisburg, Gettysburg area). I consider myself knowledgeable on that war and have not heard anything like that. Any good books? Oops, I said i would try to stay on thread. RT.<P>
> "So much to learn and so little time"


----------



## Bjd (Dec 19, 2003)

A recirc line for hot water heater run throught the bottom of the tank and from the far end of the hot water load shoul give you more hot water.

Sounds to me like some one piped this thing wrong, and or forgot to install check valves.

Without check valves the system works backwards.

BJD


----------

