What think? Tankless Hot Water

Rod Kotiga

Mike is right. We've installed several and they definatly like soft water over hard. There's a lot going on in those units and it will always need to be serviced more if your water is not slippery i.e. soft. There will also always be what they call a cold water sandwich if you use a re-circ with them as the water heater cools down in between cycles and you turn on the shower on the water will come out hot at first because of the recirc. but then about two minutes in ( depending on how far away your shower is from the water heater ) a slug of cooler water mixes through and this was the water just sitting idle in the water heater before you turned on the shower. They say you can put a small 5 or 10 gallon tank after the hot water outlet to help this cooler water mix in. Good to keep these units close to the showers.

Rod

neilc

Domestic leaking

30 gallon gas hot water heater is starting to seep.

I am considering a tankless hot water, no perticular make yet.

1 bath, 2 bedroom, 1000sq ft ranch, nat gas.

Am expecting cost to be about 3 times direct replacement of present tank due to refitting to exterior wall, etc.

Any pros or cons? comments?

Also thinking of on demand recirc at kitchen as there is a 1+ minute wait for hot water, 1.5 gallon, (50' 1/2" copper) wasted to drain,

again, comments?

any pros interested? Fairfield Ct ?

neil

Mike Thomas_2

Things to consider

Probably more like 4 times the cost. Especially if you consider special vent requirements, upsizing the gas line,etc... Constant recirc doesn't always work with on demand. The flow requirements have to trigger the flow switch to get it fire, then you are firing without much demand for heat. In my experience, unless you have the need to fill a large tub or something similar, you are better off with a standard water heater. The pay back is just not there. And they do require regular maintenance...

Charlie from wmass

neil hows your water? what heats your home now as there are other options. I do not install tankless units unless a gun is held to my head as we have some wonderful mineral rich water here in berkshire county and no one likes water softeners. the reciculating line is a good idea if over 75 feet away in mass it is required. reciculating lines often use small electric water heaters when you have a tankless unit. I say stay tank type and invest in insulating hot water lines and recirculating lines.

neilc

Details to replies,

Mike,
At 4 X's the cost it's starting to sting,,,
Have been to Rheem,
http://www.ruudtankless.com/content/resources/documents/tankless/IndoorOutdoorRTG2_42_53_UC.pdf
and understand 4 ft to operable window, vert and horizontal, or to any OA intake.
could you elaborate further on special venting needs?
Nat Gas line is 3/4 running length of house to HA Furnace,
would still need to repipe to new tankless location.
Recirc would be demand base, not constant, and would shut down on temp rise,
(6 - 12*, and locks out above 86* adjustable),
at far point, kitchen.
checkout,
http://www.chilipepperapp.com/howit.htm
Taco and Grundfoss make similar.
Maintenance I would handle the minor filter, burner by other w/ furnace.

Charlie,
City water, very mild,
Hot Air, condensing, w/AC, so no boiler or indirect, ideas?
In the end I may stay tanked, and add recirc, HW line is insulated now.
Recirc would be through added recirc line(3rd line), not Thru CW line.

Rod,
on that cold slug,
I think some manus keep the burner fan running ala post purge for a short period,
allowing instant relight of burner.
from Rheem, Troubleshooting,,,
"Fan continues to rotate after hot water
faucet is closed.
This function is to supply hot water
when the hot water faucet is reopened.
œ Normal operation. There is no need
to call for service."
I would not think to add a remote tank,
but stay with a traditional tank first.

Keep the ideas coming guys,,,

neil

Mike Thomas_2

Line Size

Depending on length and btu rating it could be as small as 3/4 inch line up to 1 inch, maybe more. You will need flush lines in heater to remove scale. This involves usually a pump, and descaler solution. Without really knowing the details of your install, I can't really say, but in general terms, I've never seen an install that will payback in any reasonable time. Those special situations, like large spa/tubs to fill is where they really work. But they work to fill the tub, all those other problems/quirks of the system are still there and will require you and your family to adapt to the tankless, cause it won't adapt to you....

kpc_53

50 Gallon

240V electric.... plenty of volume to handle your needs... no vent.... less money up front by far.

Erich_3

Navien On Demand Water Heater Is The Way To Go

You should use a Navien Model A on demand hot water heater. It has a 98% efficiency rating and is very high quality. The "A" models have a built in circulator so there is no cold water sandwich. You can see them here:

http://www.navienamerica.com/