I can't stand this type of nanny-state bullshit, with regulations stepping in to prevent things that common sense should be preventing.
The red handle provides hot water, hot enough to burn you. Be careful.
PLEASE GIVE ME BACK MY RIGHT TO CONTROL THE WATER TEMPERATURE IN MY HOUSE.
Don't know about the USA but in Canada they are legal if you have a "tempering valve" on the water heater, which mixes hot and cold to limit the output temperature.
It sounds like your tankless water heater is undersized for your situation.
Tankless heaters are generally rated for a given temperature rise at a given flow rate. If you draw water faster than it can heat it, you'll get cooler water.
Likewise, if the water coming into your home is colder, the outgoing water will be colder too. The heater can only raise the temperature so much.
It would be like trying to heat an entire house with a small space heater. If you close the doors you might be able to heat one room. Open the doors and you'll lose heat faster than the heater can warm it.
When you bought your heater you should have checked the temperature of your water supply, what flow rate you would need (how many fixtures you would be running at once), and selected a heater that could meet those requirements.
At this point, you really only have a few options.
Of course, putting low flow aerators on all of your fixtures would help too.
One way you can test if your water heater is the culprit is to open a hot water valve at a sink or washing machine outlet. Basically someplace with the "two handle" operation you are describing. If the water cools down as you open the faucet further, you know the heater isn't able to keep up.
As far as I know, single handle pressure balanced shower faucets are now required for new construction (or remodels when you upgrade the plumbing).
You might try replacing the balancing valve in the faucet, it might just be defective. Sometimes they get plugged up with grit and stop moving correctly.
Odds are the pressure balancer is crusty/rusted too. Time to do some maintenance.
Good luck,
Anthony Watson
I noticed this, and I don't like them because of this. Because you have no control of how much water comes out. . I think I've seen this kind of faucet in gym locker rooms, And they had it in the Hilton I just stayed in, though there one person's use of hotwater probably has no effect on its temperature.
However i didn't realize there were so many problems.
A) I don't know anything about the law.
Besides Hubby's suggestions, and depending on how many places this is a problem, could you replace the shower fixture with a kitchen sink style fixture, whose handle moves in two planes and with which you can adjust both the temp and the volume? I can't remember now seeing them in a shower or bathtub but I saw one in a bathroom sink a couple days ago (of course the house was 30 or 40 years old)
It might be easier, no tile work, for example, to replace the water heater.
My own bathtub/shower doesn't work like I remember it. If I don't want a blast of water, just moderate, I can turn on the hot, and then it takes only a minute adjustment to the cold to change the temperature of the mixed water. It's not bad, but I sure thought it used to work differently and I don't know how it coudl have changed.
Tankless water heaters suck and they don't really save money.
Why blame safety regulations for your crappy water heater? Or is the valve going bad? With my single handle shower faucets I turn the handle to about 11 o'clock, make a minor adjustment if needed and I'm set to shower. Makes no difference if anyone flushes a toilet, the dishwasher is filling or the other shower is going.
It is also possible the sensor in the faucet is not working properly too. You should be able to set the maximum temperature at a safe level and just turn the handle to full hot and be within showering range. Maybe a slight adjustment for seasonal cold water temperature.
Agree. Sounds like another satisfied tankless customer. I see what's going on and how it's annoying, but I'd say the root cause are the properties of the tankless. It would be solved by having a tankless sized to maintain constant water temp up to whatever the max usage rate of the whole house is. But that will likely take a much larger model, because you have to support the max reasonable load of the whole house. And if he's having this problem with just one point of use, it would likely require a much bigger unit to support two or three simultaneous draws. Alternative, as you say, is to restrict the hot water flow rate so that the tankless can keep up. Even then though, I wonder how variable their burn rate is and if they can actually maintain a perfectly constant outgoing temp rate? IDK, because I don't and won't have one, for a variety of reasons, starting with cost.
I'm not certain, but I think where I live plumbers are not allowed to install separate valves, but you can still buy them. It sounds like what you need is a real water heater. Then if you do the shower plumbing yourself you can probably switch over to dual valves. But with a decent water heater you might be happy with the old mixing valve.
There's nothing wrong with tankless as long as they are sized for the application.
As with most things, people buy the wrong thing then complain about the item as a whole. "Those things don't work" instead of "I got the wrong model".
A tankless heater designed for a single faucet isn't going to perform well for an entire house.
I looked at tankless models when we built our house. We didn't have gas available and electric models would have required major electrical supply upgrades. We have relatively cold well water so we would have needed a large model. And, as you say, they're kind of expensive.
However, I have used tankless heaters at many cabins and cottages and they perform very well when sized correctly. Best part is the hot water never runs out.
Anthony Watson
That's an inaccurate generalization.
Technically, tankless water heaters "flow", not suck. :)
As for saving money, that depends on the application. If you use hot water regularly throughout the day, you probably won't notice a major difference compared to a tanked model (other than the hot water never runs out). On the other hand, if you have a cabin or rental unit that can sit empty for days, you'll save money by not heating water when no one is using it.
Anthony Watson
I'd say even if they're sized right, the fact that in most cases you'll never recover the increased upfront costs of the unit and installation are something that's wrong with them. That cost can include running a larger gas service. The OP might run into that if he tries to put in a larger one. And the alleged savings in operating costs, I think in many cases are overstated.
There you go.
That is an advantage. How much it matters, depends on your situation. For me, running out is not a problem with my tank type. On the flip side, when my power goes out, I still have hot water, while with most tankless, you don't.
Well, yes there are some things. They are expensive. That's because they have a lot going on in the unit in order to operate properly and safely. And that means a lot can go wrong, and very few qualified technicians to fix it, usually only one source for parts, and that means repairs can cost more than the original installation.
They do have some good selling points, but consumers should know about the good and the bad before making a decision.
Because the safety regulations are the reason that valve even exists. Without the safety regulations, I wouldn't have to adjust or replace anything, I'd just turn the hot valve a little less or more to get the temperature of water I need.
As for the crappy water heater - yeah, maybe it is not the best, but if I had two-handle faucets, it would be totally fine.
Apparently two handle, old style shower valves are still sold:
So, I'm not sure it's some safety regulation is the reason you have the more popular single handle type. The single handle ones are the type most people prefer and are going into most new homes, etc. But it looks like you can have what you want. How feasible it is to change it, IDK, that depends, but it's not trivial that's for sure.
I agree you have a valuable point though, and one that you probably wouldn't realize until it's too late. Which is if you have a tankless that can't maintain a constant temperature across the flow rate when using the shower and/or shower plus other draws at the same time, then you will have the problem you describe. If that is happening with just the shower, it definitely sounds like the tankless is under sized. What make/model is it? Also something that should help would be to reduce the flow rate at the shower head, assuming it's not already limited flow.
On Thu, 09 Jul 2015 09:25:37 -0700, croy wrote in
+1
This isn't his problem. The problem is that tankless heater is not heating to a specific temperature regardless of the flow rate so at low flow the water is too hot. Changing the mix at the faucet for more cold and less hot doesn't work because then the hot water, while lower in volume, is much hotter.
Does any tankless hot water heater monitor the flow rate and output temperature and then adjust the flame to keep the temperature constant regardless of the flow? It would not be difficult to do this but a good flow meter that works for hot water is not cheap.
Why would anyone put in a tankless water heater in a residential property? Even for vacation homes it's easy to fit something that turns the hot water heater off when not in use.
I remember visiting some friends once, during a milti-day power failure (caused by ice on tress). One of the best things about going home was getting a hot shower.
I'm not sure we can state that's it's "not trivial" without knowing the situation in a given bathroom.
If the shower originally had a 2 handle valve which has been replaced with an escutcheon plate and a single handle, then reverting back to 2 faucets might not be that hard at all.
Granted, if there is only the single hole in the existing wall, no easy access to the plumbing, etc. then things do get a bit more complicated, but I don't know that we can make the "not trivial" assertion without more information.
That would seem to be exactly his problem. At a slower flow rate, it's able to heat the water hotter. If he had a unit with a much higher capacity, then he wouldn't be having the problem.
It can't heat to the same temperature at 5 gal a minute as it can at 1 gal a minute. It's very much an issue of the flow rate.
Changing the mix at the faucet for more cold
That would indeed be the problem he stated.
I would certainly hope so. Otherwise when you were drawing .1 gal a minute, you'd get steam, wouldn't you?
If you had a big family and had experiences of running out of hot water I can see it. Around here, they are putting in two tank type to support large homes, with Jacuzzi type tubs, etc. I can see putting one in there instead of two tank type.
Not so easy unless you have a predictable schedule of when you're going to be there. For vacation rentals it wouldn't work well either.
If the water is too hot at low flow, there are two likely causes:
Both are easy fixes.
I have no idea, but a standard tank model doesn't do this either. You set a maximum temperature and the heater heats the water to that level (typically 120 degrees). A tankless heater isn't really all that different. It's just heating the water as it comes in instead of preheating it in a big tank. Either way the water should always be 120 degrees when it leaves the heater.
As I mentioned earlier, the original poster should check the water temperature at a valve near the water heater. If the temperature remains fairly constant at high and low flow, the heater is probably fine. The problem is probably a defective faucet.
Space savings, potential energy savings, endless hot water, gadget wow factor. How important any of these are depends on the situation and the individual.
Anthony Watson
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