Considering Hot water recir system, advice?

[HarleySilo]

So it takes at least 30 seconds to get hot water at our kitchen faucet. Not bad normally, but when you are trying to heat a bottle up at 3:00 am and the baby is screaming it seems like an eternity.

So I've gotten the literature from HD and Lowes' on the systems they offer. around $200ish.

Questions, Do they really work as well as advertised?

Can they work in the future if we go tankless?

 

[Rancher]

So I've gotten the literature from HD and Lowes' on the systems they offer. around $200ish.

Questions, Do they really work as well as advertised?

Can they work in the future if we go tankless?

Are these systems the ones that send the cold water from the hot water side back down the cold water side? If so you don't save any time, so save $200 and just run water. Even on my hot water re-circ sytem, which uses separate plumbing, it still takes time.

If you go tankless you won't need that system. And from what I've read and from people that have installed them, you won't be happy.

Rancher

 

[Sponsor]

 

[Jimbo]

These systems do save the inconvenience of wating for the water to get hot, assuming you have the pump on continuous, or a timer, so that it is runnine when you need it. So the PROS are the convenience, and the saved water. No free lunch, the CONS are cost of energy ( heat loss in the circulation) and the side effect that you will have warm water in the cold tap briefly.

Besides the Laing and possibly one other brand you saw, consider the Grundfos Comfort System. About the same price, a little more flexible, and it puts the pump at the WH instead of under the sink. It uses crossover valves, so does not need a dedicated return line.

 

[HarleySilo]

The two types I saw, used pump at HW heater. As I understand the literature, i can install multiple crossover valves to have HW at various locations.....

What I don't understand is how does the valve know when to open and close?

 

[Gary Swart]

I've been using a Laing for about 3 years and I really like it. It requires a return line from the furthest away fixture back to the tank, which could be difficult to do in some homes. Besides the pump, the system requires a simple check valve, an air bleeder, and a ball valve. I replaced the drain spigot at the bottom of the tank with a nipple, tee, and ball valve. I got my pump new, in-the-box on **** for much below retail. There are systems that do not require a return, but I can't speak to their operation.

 

[Jadnashua]

They work, and many will work without a dedicated return line, but as mentioned, you end up with warm water at the cold line. Most of them are preset so it continues to run until the temp of the water reaches the sensor. The one I have is a Redi-Temp, which has a user adjustable sensor (a knob on the front panel) so you can set the desired shut-off. I don't need really hot water instantly, so I set it to warm. This minimizes the energy losses and the fixtures closer to the water heater are hotter (you normally install these things at the end of the line). SO, my kitchen and lavatory sink downstairs are hot, while the shower and lav upstairs are warm when you turn the faucets on, but get hot fairly quickly. Before I did this, it would take over a minute to get hot water to the shower; now it is like 10-seconds. I've got a 7-day multi-period timer on the thing so it only runs when I want.

Taco also makes a system. I've heard many people recommend the Grundfos system, but have only experienced mine.

Note, in some locales, the utility companies also give a rebate for installing one, since it minimizes wasting water while waiting for it to get hot. This helps the water utility and the sewer.

 

[Rancher]

I should have mentioned that my re-circ system is switch operated so I am not heating the ground when I don't need hot water.

Rancher

(under the slab plumbing)

 

[GoTanklessToday]

They work really well. grundfos Comfort System, the Laing Auto Circ, and the Metlund systems are really good. They all use the crossover method, which isn't as good as a dedicated return line system, but remember the old saying.. there is no free lunch. I've installed many of these systems, our customers love them. One thing I've learned, the Laing system may have the edge on homes with old crappy galv pipes. Their bypass valve will stand up to cleaning better than the plastic version that comes with the Grundfos.

The Metlund is the only real crossover type option for tankless systems, and it's unique on its own. There is a triggering device located somewhere in the system, or several places. It can be a motion sensor, or a push button. The theory is when you need hot water to recirc, you trigger the pump (that installs under the farthest fixture) and wait a bit. This system seems to be favored by the customers who are more concerned with conservation rather than convienence. Those who are more interested in the convienence part use the motion sensor version of triggering. The only problem with that is if you are going into the bathroom for a bandaid, you just triggered the recirc.

I had one customer who had a 3 story home that was experienced a 1 plus minute wait to get hot water up to the master bath. She was pregnant at the time of the work. She called me a month later to say that she was so happy with the Comfort System that if her baby had been a boy, she would have named him after me. Our customers LOVE them.

 

[HarleySilo]

Interesting, I'll need to check the name brands that I read about to fully understand the comments written here.

All of the fixtures that I'm annoyed with are easily accessable from our unfinished basement. If a dedicated return line makes it that much better, I could do it, especially for the kitchen faucet, for just the price of copper pipe and the pump. So that is the type with a pump under the sink, correct? Put on say a timer? Where does the return line run? to cold water side of HW heater? Does it reduce pressure at the faucets, meaning when you turn them on does the pump stop, to prevent hot water from going back to tank?

 

[HarleySilo]

O.K. what about Gravity Hot Water Recirculating Loops???

http://www.askthebuilder.com/147_Gravity_Hot_Water_Recirculating_Loops.shtml

I understand the theory. But, can I have Two return lines?

 

[GoTanklessToday]

Interesting, I'll need to check the name brands that I read about to fully understand the comments written here.

All of the fixtures that I'm annoyed with are easily accessable from our unfinished basement. If a dedicated return line makes it that much better, I could do it, especially for the kitchen faucet, for just the price of copper pipe and the pump. So that is the type with a pump under the sink, correct? Put on say a timer? Where does the return line run? to cold water side of HW heater? Does it reduce pressure at the faucets, meaning when you turn them on does the pump stop, to prevent hot water from going back to tank?

If you can install a dedicated return line back to the heater, then hands down that is your best method. The pump installs somewhere in the basement near the water heater. The Grundfos model we sell has a built in timer and a standard 3 prong pigtail. Install a check valve downstream of the pump and run the return line into the cold inlet of the heater. Some remove the drain valve and let the recirc go in there, but I don't like that method as well. (personal preference). You also need a ball valve on both sides of the pump, and a boiler drain upstream of the pump so you can bleed the system.

 

[PEW]

We have a Laing in our kitchen which would require about 5 gal of water to get hot water.

I wired ours as part of a HA system where after pushing a button on the regular light switch, it will run for 20 minutes. For our life style it works fine, rather than on the internal timer or continuous running.

Paul

 

[Ginahoy]

One thing that hasn't been emphasized is how an on-demand water pump, like the one made by Metlund discussed above, differs from a circulation pump, whether operated by timer, switch, or continuous. Taco makes an on-demand pump. I like the one made by Chilipepper:

http://www.chilipepperapp.com/howit.htm

In my opinion, an on-demand system is superior to a circulation pump. It only operates as long as necessary, shutting off automatically when hot water reaches the tap. This conserves both energy and water. OTOH, a conventional circulation pump *wastes* energy. Moreover, on-demand pumps are more convenient than circulation pumps, except when left to run continuously, which is obviously a huge waste of energy.

The most common way to activate an on-demand pump is with a button. And since it operates at a much higher flow rate than a circulation pump, it only takes a few seconds for the water to reach the tap (depending on length of supply line). In any case, it's faster than trying to operate a conventional circulation pump like an on-demand system.

I live in the desert. In my town, circulation pumps on timers are now required by code. Big mistake in my opinion. Most folks I've talked to unplug them after they get their first couple of energy bills. Those that do use them typically endure the inconvenience of manually control, and even then, people tend to use them sporadically.

On-demand systems are a bit more expensive but there's a payback in terms of convenience and energy savings.

David

 

[Dubldare]

The beauty of the Grundfos comfort system is that multiple tees can be installed throughout the home, which can really help if your kitchen isn't at the back wall of your bathroom.

The tee's work on a thermostatic method, whereby the shortest loop will satisfy and shut off first, and the next and so on. Try balancing two or more loops in a conventional system.....good luck.

If you go tankless you won't need that system. And from what I've read and from people that have installed them, you won't be happy.

Ahh, the misinformed.

 

[Rancher]

I live in the desert. In my town, circulation pumps on timers are now required by code. Big mistake in my opinion. Most folks I've talked to unplug them after they get their first couple of energy bills. Those that do use them typically endure the inconvenience of manually control, and even then, people tend to use them sporadically.

David, Sorry but the Cochise County Board of Supervisors just approved the change to the zoning regulations on December 5th of 2006, and it was for new construction... So I doubt if "most" folks are unpluging them since it typically takes longer then 7 weeks to construct a house.

Here's what they approved:
Hot Water on Demand: In new construction, a hot water system will be installed to provide hot water on demand at the point of use in sinks and baths/showers. Recirculation devices shall include timers, temperature sensors or remote control operation. Point of use hot water heaters that serve individual fixtures or other alternatives that deliver hot water at each fixture within a waiting period of 15 seconds or less are acceptable.

I installed a hot water re-circ pump and plumbing in the house I built 12 years ago, it's switch operated with a timer than limites the on time to 10 minutes, I'm sured it has save me money in less propane needed to heat the water, and less electricity to pump the water out of my well.

Rancher

 

[Ginahoy]

David, Sorry but the Cochise County Board of Supervisors just approved the change to the zoning regulations on December 5th of 2006, and it was for new construction... So I doubt if "most" folks are unpluging them since it typically takes longer then 7 weeks to construct a house.

Hey Rancher. I live in Sierra Vista, which passed the relevant code on June 8, 2000 (similar language to the new county code). I've talked with at least a dozen people who live in homes built since then and more than half have disconnected their timer altogether and the rest attempt to set the timer to encompass typical usage patterns, or manually plug in the pump (when they remember). Only one person told me they set their timers for less than an hour -- he uses the minimum setting, which is 20 minutes on his timer. But he admits he often has to let the water run if he needs hot water during at other times. Not a scientific study, but it's consistent with anecdotal information I got from one of the researchers at Oak Ridge National Labs who published a major study on this topic.

The code does not require a timer-only system, but that's what gets installed in the vast majority of homes because it's the least expensive option. The one you described is much more efficient because it allows you to activate the pump only when you need hot water, and it turns off on its own. But even a ten-minute run time is wasting energy compared to the type I described that only runs as long as needed.

Having said that, I'd be thrilled if the city and/or county set yours as the minimum baseline.

David

 

[Bob NH]

A small point-of-use heater saves energy and gets you water quicker. It is fed by the regular hot water line and supplies immediate water. Because it is fed by hot water, the only electricity that is required is to maintain it hot. No switches. No circulating pump. No return pipe. No circulation to waste heat, or to add to your A/C load in the summer.

The point of use heaters are not adequate for supplying all of the water for a shower. They supply enough to get you hot water instantly and the hot water from your main heater kicks in to supply the greater demand before the POU heater runs out. The volume of the point of use heater is several times the volume in the supply pipe so it mixes with cooler water in the pipe and maintains hot water until the hot water from your main heater arrives.

The Ariston GL 2.5 is an example of a point-of-use heater. They operate on a 115 Volt circuit.

 

[Ginahoy]

The Ariston GL 2.5 is an example of a point-of-use heater. They operate on a 115 Volt circuit.

Hi Bob, I've been curious about these for the reasons you mentioned, especially in homes where primary water heater is electric. But it seems like the cold water stored in the supply line would overwhelm the recovery capacity of the little 1.5kw heater. Of course, this wouldn't be an issue for just washing hands, but when showering or shaving, wouldn't the water run hot-lukewarm-hot?

David

 

[Teamo]

I am planning to build a recirculating loop when I replace my electric hw tank soon. I was planning on running a loop all the way to the furthest fixture and return to the cold water supply line at the hw heater into a tee with a check valve. I was thinking of using a bronze circulator and a a clamp on aquastat with an additonal check valve installed somewhere in the hot water loop as well as installing an expansion tank somewhere in the loop. I will insulate all of the pipes to minimize heat loss in the loop. Does this look like it will work with this type of setup? Also I read something about an air valve in one of the previous answers. What does this do? Thanks

 

[Jadnashua]

You plumb the input of the point of use heater with the hot line, not cold, so as it starts to empty, it is refilled with the hot water. Since it is close to the outlet, you get nearly instant hot water.