PDA

View Full Version : Instant hot water heaters



Brian Hale
03-18-2006, 10:07 AM
Anyone have one of those instant hot water heaters, the kind you see mounted in sinks for a hot cup of water?

LOML is on her 2nd of 12 rounds of Chemo therapy and anything colder than room temp is painful and causes her muscles to lock up, hence, washing her hands requires the hot water to run till it gets warm enough and it seems like such a waste.

I'm wondering if these things have a variable temp setting and if they would work for warm (not hot) drinks and hand washing.

Thanks!

Brian :)

Cecil Arnold
03-18-2006, 11:04 AM
Bryan, don't know about the heaters but think they might, as it might be a liability issue. Sorry to hear about LOYL, and wish her the best.

Alex Yeilding
03-18-2006, 11:38 AM
Brian, check out a recirculating heater like this one (http://www.grundfos.com/web/HomeUs.nsf/Webopslag/PAVA-56TMVA) . I'm considering this just from a comfort standpoint. I was real skeptical at first because of no return line, but the way I understand it now, there is a very small flow, controlled with the valve just to keep warm (not hot) water available at all times. I think you will have to wait for hot, and keep adjusting H/C mix as the water runs and the hot gets hotter (But the cold will also be getting cloder as the recirculated water is flushed out.)

There are other brands that put the pump under the sink. I like this approach better, since I can put valves at multiple locations much more cheaply.

Ken Garlock
03-18-2006, 11:41 AM
First off Bryan, I wish the best to your wife in her battle.:)

Regarding the water heater, I can't say with certainty, but I think the instant heater that replaces the soap dispenser is at a fixed temp suitable for making a good hot cup of coffee.

Let me suggest that you investigate an electric tankless waterheater (http://www.hotwaterheater.com/model-h-12-2.htm)that is sized to work on your existing hotwater line to the sink. That way, you will have the instant hotwater you need, and when the hot water from the big tank finally makes it to the faucet, the instant heater will shutoff. The advantage is that you can regulate the water temp you want with the sink mixer faucet. Then you have the best of both worlds, instant hotwater, and direct control of the water temperature.

Stu Ablett in Tokyo Japan
03-18-2006, 12:41 PM
That is all we run here in Japan, the only tank heaters we have are either very small under the sink units, or HUGE ones at factories or such.

Ours are all natural gas fired, but I've seen them in electric too.

The work great, the one in the bath is only about 6' from the bath, so we have hot water in seconds, and all the hot water for my wife, TWO daughters and I to have LONG showers if we like, you just don't run out, as long as you have water and gas to heat it.

Best to your wife!

Cheers!

Brett Baldwin
03-18-2006, 1:04 PM
Another option to consider would be one of those very small electric water heaters that will fit in the cupboard under the sink. I'm not sure exactly how much they hold (< 5 gal.) but for supplying a sink faucet they do a great job.

Doug Shepard
03-18-2006, 2:00 PM
The Insta-Hot dispensers for making coffee/tea/etc are way too hot. The water isnt at boiling temp but it's pretty close. The one mounted to my kitchen sink is maybe the 4th or 5th one over about 20 yrs. They work great for drinks but they seem to have a relatively short shelf life. But way too hot for handwashing.

Cliff Rohrabacher
03-18-2006, 3:08 PM
Chemo sucks. I did radiation. That sucked too but chemo is worse.

Oh yeah I think Bosh has a good one.

Frank Hagan
03-18-2006, 11:48 PM
Brian, check out a recirculating heater like this one (http://www.grundfos.com/web/HomeUs.nsf/Webopslag/PAVA-56TMVA) . I'm considering this just from a comfort standpoint. I was real skeptical at first because of no return line, but the way I understand it now, there is a very small flow, controlled with the valve just to keep warm (not hot) water available at all times. I think you will have to wait for hot, and keep adjusting H/C mix as the water runs and the hot gets hotter (But the cold will also be getting cloder as the recirculated water is flushed out.)

There are other brands that put the pump under the sink. I like this approach better, since I can put valves at multiple locations much more cheaply.

I agree with this approach ... I know several people who have installed these, and they work well. There are several different kinds, but you can't go wrong with Grundfos. Good company. And they are a heck of a lot cheaper than an "on demand" water heater.

Jerry Clark
03-19-2006, 10:28 AM
Quote:
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by Alex Yeilding
Brian, check out a recirculating heater like this one (http://www.grundfos.com/web/HomeUs.nsf/Webopslag/PAVA-56TMVA) . I'm considering this just from a comfort standpoint. I was real skeptical at first because of no return line, but the way I understand it now, there is a very small flow, controlled with the valve just to keep warm (not hot) water available at all times. I think you will have to wait for hot, and keep adjusting H/C mix as the water runs and the hot gets hotter (But the cold will also be getting cloder as the recirculated water is flushed out.)

There are other brands that put the pump under the sink. I like this approach better, since I can put valves at multiple locations much more cheaply.
</TD></TR></TBODY></TABLE>

This looks like a nice way to have hot water, but it requires that the hot water be looped back to the tank. The loop line connects to the fitting at the bottom of the tank. So it does require a return line of sort. Faucets that are on a single line and long distance from the tank will still have cold water until the hot water in the loop line replaces it.:cool:

Russ Filtz
03-19-2006, 10:55 AM
I checked into this a while back for work. It seemed most of the simple plug-in models (120V) were pretty puny in the actual heat input. You need to check the ratings of temp rise vs a standard flow rate (forget what the flow was) Most of the 120 models were at most 50 degrees rise I believe. That's from ambient, so if you live north don't expect a steaming cup of joe out of it in Winter!

You need to really look at 240V minimum and for really good specs, 277V and 480V models. For residential, you're pretty much locked into 240V max.

Ken Garlock
03-19-2006, 11:10 AM
Russ, you are right on target. The part of the country you live in will dictate the size of the unit you will need. Information of that type is given at the site I referenced in my post above.

I have a 36 KW unit to supply our master bath and hall bath. It required 3 50 amp circuits to supply it. Just turning on the hot water will bury the 24 KW pole pig that supplies the house.:D So long as the lights don't dim, which that don't, I am happy.

Regarding the recirculating hot water system, IMO they are a waste of energy. You need a small pump to make the water move, and your heater will run more to provide make-up hot water for the cooling that goes on in the pipe loop. As Milton Friedman like to say, there is no such thing as a free lunch.

Don Wurscher
03-19-2006, 11:37 AM
Brian
I have had the Grunfos system installed in my house for about 5 yrs now and I am very satisfied. Not one single problem yet.

The system requires the installation of a pump (with built in timer) on the hot water side of the hot water heater, ( I mounted mine on top of the HW heater as it was the easiest place to get at) and a temp sensitive valve under each sink you want to control.

There is no need for a return line to the hot water heater, as it uses the existing cold water line.

The only drawback I have found is in the summertime, you have to wait a very short while for the cold water line to cool down, otherwise it works great.

My furtherest bathroom is about 35' from the HW heater, and there is warm water at the fauset the minute you turn it on.

May the LORDS face shine upon you and yours, and only good things come your way.

DLW

Frank Hagan
03-19-2006, 1:58 PM
Quote:
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by Alex Yeilding
Brian, check out a recirculating heater like this one (http://www.grundfos.com/web/HomeUs.nsf/Webopslag/PAVA-56TMVA) . I'm considering this just from a comfort standpoint. I was real skeptical at first because of no return line, but the way I understand it now, there is a very small flow, controlled with the valve just to keep warm (not hot) water available at all times. I think you will have to wait for hot, and keep adjusting H/C mix as the water runs and the hot gets hotter (But the cold will also be getting cloder as the recirculated water is flushed out.)

There are other brands that put the pump under the sink. I like this approach better, since I can put valves at multiple locations much more cheaply.


</TD></TR></TBODY></TABLE>

This looks like a nice way to have hot water, but it requires that the hot water be looped back to the tank. The loop line connects to the fitting at the bottom of the tank. So it does require a return line of sort. Faucets that are on a single line and long distance from the tank will still have cold water until the hot water in the loop line replaces it.:cool:

I'm surprised at their website ... they do have that statement if you click on the "How it works" link at the top. But for retrofits, there is a method by which you simply push the hot water into the cold water line right under that sink. Since the hot and cold water line are connected, this simply pushes the cold water in the hot water pipe into the cold water piping. A picture is attached. Also, you can access the installation manual for this product at http://www.us.grundfos.com/web/Download.nsf/Pages/66D8FEAE045F0F2588256B020059F20B/$File/L-UP-TL-043.pdf (that's a PDF file, so it may take a while to load.)