We got a tankless water heater last year to cut down on use of fuel and be more efficient. We were hoping that it would also address the problem we have with our sinks; it takes a long time to get hot water to them, especially in the kitchen. The tankless heater turns out to be much better for the bathroom sinks which are right above the unit, but it still takes a long time for the warm water to reach the kitchen, and once it's hot, if I cut back on the flow to save water, it turns cold again. We were looking for a way to provide hot water more efficiently to that sink but the units we've looked at don't seem to do the trick; they look more like instant hot water devices for making tea. Any ideas?
I installed a tankless electric heater back in 1985. All my plumbing is in close proximity with the kitchen sink wall adjoining the 2 bathrooms which are back to back. I had the heater installed in the supply line before it split off to any of the fixtures so it could to serve the whole house. They had been used for years overseas but were new here. It was advertised as being capable and it worked very well ...when it worked.
Within a month or two, I had to replace the element. Then again. I figured it was just a lemon so I ordered another one. Same thing. So I did away with it and got a regular hot water heater that had to go in the garage since there was no good space for it otherwise. So all this time, I've been living with wasting a lot of time and water waiting for it to arrive at the fixtures.
I honestly don't know what the problem was with mine. I theorized that it might be suffering from excess vibration or shock when the well pump shuts on and off. I disected mine and the element looked like nothing more than a light duty coil as in delicate. I was so disappointed and disgusted that I've not kept up with any developmental progress. I think they're a great idea but I'll wait until somebody else works out all the bugs.
They're supposed to work as long as a faucet is open so the only thing I can think of for your problem is that you must have a very long and uninsulated run from your sink to the unit. It's obviously cooling down before it reaches the kitchen because the reduced volume moves at a slower rate. The simplest fix is to quit trying to save water. The only other options are to try insulating the pipe entirely or run a new electrical supply and install another one under the sink. Probably none are appealing.
Twiggy, we have a run of maybe twenty feet in the basement ceiling from the tank to the kitchen faucet. The basement isn't heated but it's much warmer than outside, of course. It just seems to take a while for the cooled water to run out of the line and the heated water to replace it. The guy who installed it said that there is sometimes a brief period once it heats up when the warm water gives way to cold and then the warm water resumes. I forget the reason - something about the way the units work. I have found that if I turn the faucet on full I don't get that, which is nice for showers!! But if the draw on the heater is lowered it seems to trigger a shutoff.
I hate to waste the water, but that may be our only option. I try to do whatever I can with cold until it heats up but it would be so much nicer if it worked better. How disappointing!
Molamola, it's not insulated but it doesn't need to be because it's in our basement, which never gets below about 50º. The water in the supply pipe between the tankless water heater and the kitchen sink cools between uses, since it's sometimes several hours before we need hot water at the sink again. Then by the time we've gone through the cool water so the hot water can reach us, it takes a while and I'm washing in cold water at first. Tough on the hands and not so good with grease!
My water heater is at the opposite end of the house from the kitchen. (one bathroom house) I don't like wasting water while I let it run until it is hot. I have an old fashioned graniteware dishpan, and a teakettle, and as soon I am through cooking, I fill them with water and put them on my ceramic cooktop. I used to put them on my woodstove, and am wishing for one again.
There is usually enough heat left to warm the water for dishwashing without using any extra electricity. I am trying hard to learn to cut back, as I think electricity soon will be much more expensive.
I also wipe out all dishes and pans with the white paper napkins we use at dinner, so my dishwater doesn't get yucky. Then the napkins go into my compost, along with my newspaper full of peelings, leaves, etc from meal prep.
That's an interesting way of handling it, Caliche. Wouldn't work on my gas stovetop, and really if there's chicken or porkfat on the dishes they need hot water to get them completely clean. My scraps go to the chickens or into the woodstove.
Greenhouse Gal, nope ...that method won't work on a gas stove, and my dishes are washed with really hot water too, no matter what I have served.
By the time I have run enough water for the dishpan, the tap water is hot and available for rinsing.
I didn't mean to imply that I use no hot tap water, but that the advantage of a glass top stove is similar to a wood stove in that it holds heat that is already available.
And that I don't relish wasting water down the drain.
No, we hate wasting the water, so I wash in cold until it heats up, and just do things like the glasses first. But it's hard on the hands, as I've said, and I felt sure that there would be some workaround. Oh well.
I've been thinking. I think there is a very good possibility that your uninsulated 20' run is guilty when you turn the flow down. That foam pipe insulation they sell at home depot or lowes is fairly cheap and childs play to install. My longest runs were about 5' and all inside the house. No matter what the flow, the water got hot enough to take the hide off.
Now if you open the sink faucet only half way and it maintains a constant temp at the sink once it maxes out, you'll know the flow switch is calibrated right.
I'm thinking that when you turn the faucet down, the water velocity in the pipe is choked down to the point that it's like an impact which sends shocks back to the check valve and back again to your fixture which slowly permits the passage of the cooling water. A certain amount of water then must be released before the heater cuts on again and then all of the pipe's contents must pass before the newly heated water appears.
All of my faucets have areators and flow limiters except the tub. It only takes 1/4 the time (or less) for hot water to reach the tub as all the others due to the velocity.
I really think insulating that pipe as well as possible would be a big help and possibly the whole solution.
Podster, that's what we were thinking about, but the ones I'm seeing seem to be separate from the other waterline, rather than piggybacking on it and allowing the other to take over once the water warms.
I wondered about that... I would pick the brain of a plumber that I knew and trusted.
Of course, do not ask sales people as they will tell you what they think you want to hear.
Perhaps email an inquiry to the manufacturers of a few different models.
If all else fails... it may still be the economical solution for that work station as it is probably used most frequently.
I had a "demand only" hot water heater (that I installed) in my last home. I think it was a "Bosch" electric. I checked the "point of use" models and they did not recommend "piggy backing" with another hot water source.
The reason the water turns cold when the flow is reduced is simple - a certain amount of flow is required to tell the unit to turn on and heat water. Go below that amount of flow (or flow rate) and the unit shuts off and none of the water passing through it is heated. There may be an adjustment within the unit to lower the required flow rate for operation.
Research is needed for more information so if you need send your make/model and I will look into it as soon as I can.
I know this doesn't help the low flow issue, but our method of dealing with the cold water in the pipe (kitchen is about 20 feet from the heater) is to keep our watering cans in the kitchen and fill them with the cold water. It's then used for houseplants, humidifier, and the garden.
In our kitchen sink, to save water and reduce DHs bad habit of spreading germs around the kitchen via the faucet handle, I installed the foot pedals that used to be common in hospitals before the motion sensor faucets were popular. Now the water doesn't have to run the entire time when rinsing and you don't have to touch the handle when your hands are really dirty. It was a pain in the you-know-what to install but we use it all the time. Now when I go to other people's houses I try to turn on their sink with my foot.
Katlian, I never heard of foot pedals for a sink! Boy, I would love that! My DH is a phenomenal cook - but a very messy one. I don't know how many times I've gone to turn on the faucet and there was some kind of gunk/food/sauce on it, lol. Yuck.
I might look into that when I remodel the kitchen...whenever that will happen.
That's funny that you try to turn on other people's faucet with your foot. I guess it's a habit, huh? :)
Your plumber will probably think you're crazy but it's worth a try. I wanted ours to still have the pull-down type faucet and be able to use the regular faucet for filling the sink so it took about three days of cussing and several trips to the hardware store to get it right.
My DH also likes to cook and is very messy. If we ever remodel the kitchen it's going to have flat cabinet doors because I'm tired of trying to scrape the gunk out of the joints on the ones we have.
I installed a tankless electric water heater in my business' restroom several years ago to save space as well as money when the old water heater went out. We just needed limited hot water for hand washing, so it seemed an ideal solution.
The thing shorted out and nearly caused a fire when it was just a couple of months old. I was lucky that it happened when I was there, smelled it overheating, and cut off the power. I hate to think how much damage a fire would have done to adjacent businesses as well as my own. Maybe the newer ones are not as dangerous, but I am not about to find out!