Tankless Water Heaters anyone? - PeachParts Mercedes-Benz Forum

TheDon · #1 06-04-2011, 10:49 AM

So, what can you tell me about these things?

Hatterasguy · #2 06-04-2011, 10:52 AM

Gas or electric?

The gas ones are quite good, I have installed them on a number of houses.

The only downside on an existing house is you may have to run a larger gas line from the meter, since when they are on they use a lot of gas!

865sp300e · #3 06-04-2011, 10:52 AM

Quote:

Originally Posted by TheDon

So, what can you tell me about these things?

They don't have a tank.

chilcutt · #4 06-04-2011, 10:56 AM

Electric, tankless water heaters are just about all that are used in Asia. Warm up time is 4-8 minutes, and you have plenty of hot water to do what you have to do...then you simply turn it off. They are nice, and very simple to install.

kerry · #5 06-04-2011, 10:58 AM

Had one in a condo I lived in. Very good. They are rated according to the volume of hot water they can produce. Smaller ones preclude the operation of two hot water using appliances at one time like a dishwasher and clothes washer.

TheDon · #6 06-04-2011, 11:02 AM

Electric of course. Dear girlfriends water heater is leaking and I read about tankless heaters and how they are cheaper to operate than a tank.

chilcutt · #7 06-04-2011, 11:09 AM

To install, all you need are some low-voltage electrical skills. gotta run a power source. Some basic plumbing skills..gotta run water lines. If the shower enclosure is tile, you need a drill/tile bit. Total install time is usually 1-2 hours.

Besides getting rid of the leaking water heater, you also get to become a hero to your girlfriend.

TheDon · #8 06-04-2011, 11:12 AM

I'm thinking a tankless unit to replace the regular water heater.. Which means upgraded wiring and a higher amperage breaker. Not something I can do.

I can do plumbing, I can do electronic stuff for cars.. But honestly, talked about in the thread about the garage issue.. I do not like working with 110v. I'm not a pro and I don't have the training/know how to deal with it.

ah-kay · #9 06-04-2011, 11:23 AM

2 issues with tankless water heater. Flow rate and temp is the key.

1) Shower electric heater - one normally requires hefty cables if the water demand is high. May run off 2 phases 110V.

2) Gas heater - better than electric. In the past, the 'tank' does not last long as it may be constantly firing. It may have been improved in recent years.

Need above average DIY skills to install either one.

aTOMic · #10 06-04-2011, 11:36 AM

I got a Bosch electric from CPO (Link below). CPO sells a lot of recon and bargain tools. FOUR YEARS after I bought it, it leaked a tiny bit. They sent me another, better Bosch HWH no charge! They didn't even want me to send the old one back! I couldn't be happier with the customer service!
As for the H2O heater, the only complaint is the temp can vary depending on flow, but no big deal. Also, when you have the hot on very low flow the sensor will not turn on the unit, remedy this by setting the temp adjustment to a lower setting than usual so users won't mix as much cold with the hot. I can tell when the thing goes on the lights dim(!) only because we have dimmers in the bathrooms set <50%, it's not a big change but you can see it if you look.

Cautions: The electric that Bosch USED TO recommend was inadequate*; you need to go big, in this case that means a 240v 120a circuit. I am no electrician, but I re-routed three breakers, (3 x 40A=120A, easy) that used to supply our ceiling heat, to the HWH, no biggie. You'll need to be sure your house has the necessary wiring, 200A from the street - if not you'll pay $1000+ to an electrician and/or the power co to set it up.
*Bosch reasoned that us southern residents would have warmer incoming water so we wouldn't need to raise temp >55 degrees. Wrong! The water in NY (my real home) is a constant 60 cause the LINES ARE BURIED deeper, but here in TN one can tell the outdoor temp by the cold water temp. If it's 95 out, the temp is 70. When it's 30F out = 45 degree H2O! and 90 degrees is a cold shower. I've learned that three degrees can make a big difference in the perceived temp of my shower!
HTH,
-Tom

The one I have:
http://www.cpotanklesswaterheaters.com/powerstar-ae125-whole-house-electric-tankless-water-heater/pwsnae125,default,pd.html?start=5&cgid=bosch-whole-house-tankless-water-heaters#pr-header-pwsnae125
The CPO HWH site:
http://www.cpotanklesswaterheaters.com/on/demandware.store/Sites-BTWH-Site/default/Default-Start?ref=cpoboschsearch
The main site - cheap Bosch, Milwaukee, lots of other tools:
http://www.cpotools.com/on/demandware.store/Sites-Bosch-Site/default/Default-Start?ref=em20110603

10fords · #11 06-04-2011, 11:45 AM

I have bid on about 10 electric tankless installations and all of them have ended up abandoning the project or going with gas. The amount of electricity needed to run one for an average single family dwelling, about 125 amps at 240 volts, is just to much of a burden on a normal 200amp service. The only practical application I have seen of an electric tankless is in an industrial setting with a 600 amp or more main service. Don't you have gas available? Using electricity to make heat only makes sense if you have no other option.

TheDon · #12 06-04-2011, 11:50 AM

Sadly, no gas.

I'll keep reading up. Regardless the water heater needs to be replaced. I've replaced regular water heaters before, easy stuff.

10fords · #13 06-04-2011, 12:10 PM

Quote:

Originally Posted by TheDon

Sadly, no gas.

I'll keep reading up. Regardless the water heater needs to be replaced. I've replaced regular water heaters before, easy stuff.

What size is your main electric service? If it is 100 amp you will need to do a service upgrade. Can you get propane? That is what a few of my customers ended up doing and it was still way less than a service upgrade and the associated wiring for the electric tankless. Did you at least get your girlfriends garage door problem fixed!

kip Foss · #14 06-04-2011, 12:22 PM

Ah-kay,

There is no such thing as 2 phase 110V. It is single phase 120V. You don't get into 3 phase until you get to 240 and then it is usually a commercial or industrial application. Most houses have 240V service which is where you get the 240 for the clothes dryer but it is made up of 2 single phase 120 lines. You can get a sort of pseudo 209 V 3 phase for running larger ac units from a incoming 240v single phase line but I am not sure how they do it.

I have 2 Paloma gas tankless heaters and they are the best thing going. In 25 years I have put in an $11 diaphragm in each. They are expensive to buy but good over the long run if you have a big family. The only problem I had with them and teenagers is that once they find out that the hot water is endless they tend to use it. A 10 minute shower can turn into a one hour sauna.

I don't know how much electric will save because resistant heating from electricity is very expensive. Still it is a bit cheaper than having to keep 40+ gallons of water hot all the time in a standard electric tank type heater.

aTOMic · #15 06-04-2011, 12:52 PM

Quote:

The only problem I had with them and teenagers is that once they find out that the hot water is endless they tend to use it. A 10 minute shower can turn into a one hour sauna.

X2!!
Not just teenagers, wives, too! ;^p

This reminded me of another caveat; if the power goes off you'll be instantly out of hot water. Here in TN it goes off a lot from storms - when one should not be in the tub/shower anyway (insert Darwinism joke here). That said, we have never been affected by power loss>>no hot H2O.

In Fla, especially in a two-user household, you may be able to get away with the 120v/60A system (meaning no additional wiring beyond what the original HWH used). Does your supply feel colder in the winter? Do you even HAVE winter? If not, I advise you to measure the incoming water temp, and your GF's shower temp (seriously). The spec sheets will tell you what temp rise is possible at a given flow rate. Add the supply temp to the temp rise; if it's > GF'sST ( GF's shower temp), you are safe!
I originally wanted a gas-powered unit, too. They are at least 2X the cost of electric but last several times longer. The install in my house would've been more complex. (anyone going with gas, get one that ignites without AC power. There are several with battery-powered ignition, and some even generate the power using a tiny water powered turbine)!