Tankless water heaters vs HW tanks

flyingvan · July 30, 2012, 08:11:04 PM

I've installed 3 Bosch Aquastars now----I really like them. THe cold water sandwich is very, very brief. I have not had any issue with the low flow not kicking it on.. They are very well built. I get the ones with a pilot light to provide a little heat to keep them from freezing----but it doesn't seem to help. So my two complaints are, they freeze really easy so I stick a trouble light with a 20 watt bulb in the housing when it gets cold. If the power fails I drain them. Second, the pilot has a little screen filter that gets clogged once a year or so. Very simple to clean out, and less work than draining the old tank style ones to keep the silt down annually. We never run out of hot water (I suppose eventually the propane tank goes empty)

MountainDon · July 30, 2012, 09:20:56 PM

The potential for freezing is the main reason I decided tankless would not work for us off grid.

I've lots of praise for the Bosch.

July 31, 2012, 12:26:35 PM

When I install them I create a bypass underneath so draining them just involves closing two valves and opening one. Since it's bypassed all the plumbing still works and you don't get backflow from a faucet with a mixer. I need a valve that screws to a hose bib that opens when it gets below freezing---the water heater would kick on, warm everything up, and be good for awhile. It would just automatically spurt hot water every so often.

AdironDoc · August 08, 2012, 01:21:09 PM

Quote from: MountainDon on July 30, 2012, 09:20:56 PM
The potential for freezing is the main reason I decided tankless would not work for us off grid.

I managed to freeze both of mine, despite draining them per instructions. I'm now hoping my new Rheem "freeze proof" won't meet the same end.

I know this has been beat to death in many threads, but I'd like to see a study showing what the actual energy difference ends up being for a 3 day weekend "occasional user". Both types need to heat a given amount of water. That much is the same. The difference will be that the tanked needs that water kept hot. Ergo, it will take more energy and depend largely on the insulation/thermal efficiency of the tank. Also, the wasted energy heating water eventually left to cool once the door is closed and everyone leaves for home. Probably not much in the short run. Tank vs Tankless.. like religion and politics, I suspect there will be no peace.

At least we can all agree we enjoy a nice hot shower.

PorkChopsMmm · August 08, 2012, 01:28:45 PM

Quote from: AdironDoc on August 08, 2012, 01:21:09 PM
I managed to freeze both of mine, despite draining them per instructions. I'm now hoping my new Rheem "freeze proof" won't meet the same end.

Make sure you leave electricity plugged into the Rheem unit. I did not and mine froze even when drained. I think the free-proof part are little micro-heaters that keep the copper tubing from icing up. If it does freeze you can replace the broken components. Rheem shipped me 2 replacement parts, and while I had to take most of the heater apart, they were easy to replace.

Good luck!

August 08, 2012, 01:41:48 PM

Quote from: PorkChopsMmm on August 08, 2012, 01:28:45 PM
Make sure you leave electricity plugged into the Rheem unit. I did not and mine froze even when drained. I think the free-proof part are little micro-heaters that keep the copper tubing from icing up. If it does freeze you can replace the broken components. Rheem shipped me 2 replacement parts, and while I had to take most of the heater apart, they were easy to replace.

Good luck!

Thanks for the tip! I'll make sure and leave the power on, or, blow out the lines with compressed air just to be sure. I haven't hooked the gas line up yet but I'm looking forward to my first long, long, hot shower.

PorkChopsMmm · August 08, 2012, 02:03:01 PM

I *did* blow my lines out with compressed air and mine still froze. Doesn't matter. Rheem won't (or won't easily) warranty a unit with freeze damage if it has *ever* had the electricity disconnected. Ever. So says their warranty department. They did me a favor as they have no techs in my area and would have to pay a random plumber with no tankless experience to try and fix it. I chose to fix it myself with their warrantied parts.

I wish I would have known that prior to buying the unit. It is not in the documentation provided with the unit. That being said, I think it provides very little power to the micro-heaters so I am hoping my solar set up doesn't take a hit. We shall see.

AdironDoc · August 08, 2012, 03:10:49 PM

Quote from: PorkChopsMmm on August 08, 2012, 02:03:01 PM
I *did* blow my lines out with compressed air and mine still froze. Doesn't matter. Rheem won't (or won't easily) warranty a unit with freeze damage if it has *ever* had the electricity disconnected. Ever. So says their warranty department. They did me a favor as they have no techs in my area and would have to pay a random plumber with no tankless experience to try and fix it. I chose to fix it myself with their warrantied parts.

Wow! well, I'll definitely be leaving the power to the unit on. I don't want to find that the same thing happens to me.

Quote from: PorkChopsMmm on August 08, 2012, 02:03:01 PM
so I am hoping my solar set up doesn't take a hit. We shall see.

I'm in the same boat on that one. I have 3 panels feeding eight 6V batteries. I didn't want to use them between visits, but I'll be making it a priority. Thanks for the sober advice on their warranty.

Cheers,
Doc

MountainDon · August 08, 2012, 05:50:09 PM

It should not require saying, but just in case.... Be certain the heater drain is not so high with the inverter "on" all the time as well, that the batteries would be run down to a dangerous level if there are several cloudy days in a row. No sense adding damaged batteries to a heater that then freezes anyhow. (I have no idea what those heaters draw, but that scared me away from the on demand heaters....

August 09, 2012, 08:23:13 AM

Bosch Aquastar doesn't take any electrical power, by the way..