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Posted by BobK207 on April 3, 2008, 3:21 am
> Since there's been some discussion about these critters here lately, I
> thought I'd add my take on them. I have three customers who actually
> have them, so I speak from some experience.
>
> First of all, the answer to questions like "should I install one?", "are
> they more efficient/cheaper/better than a tank heater?" is definitely
> "it depends". It depends on (in no particular order):
>
> o where the heater is installed (how far it is from the farthest faucet)
> o how big the heater is
> o the water usage pattern
>
> The last probably being the most important.
>
> Two of my customers have the same type of older-generation tankless
> heaters (Aquastar, a French-made unit, now handled by Bosch for spares).
> Two of them are installed in the attic crawlspaces of a
> commercial/residential building, probably because the remodeling
> contractor didn't want to sacrifice any more space in the living units
> than necessary (and also simplified venting, since they're right under
> the roof). This makes these two a pain in the ass to service; I've
> overhauled both of them (replacing water valves and thermostats). Still,
> they operate pretty well.
>
> One of these had an odd setup, which it took me a while to figure out.
> Someone had written "OPEN 3/4 TURN" on the inlet valve, and it turned
> out that sure enough, the heater would simply not function correctly if
> it was opened any further. Not enough hot water in the shower, though
> the kitchen sink was OK. The culprit was the shower valve, which was a
> strange one that was full-on with temperature control; there was simply
> no way to have anything less than full flow in the shower. This shows
> that there's a definite limitation to how much flow these heaters will
> handle.
>
> Another customer has this same heater in their fairly large house.
> They're very happy with it; they have plenty of hot water and their gas
> bills are lower.
>
> My other customer just installed a Tagaki heater outside her house. This
> unit is remarkably small, requires no venting, and supposedly has a much
> higher capacity (and is more efficient). (Having electronic ignition
> doesn't hurt, either.) I'm told that this is pretty much the state of
> the art today. Too early to tell how it'll affect her gas bill.
>
> One thing that ought to be considered is insulating hot water pipes to
> further avoid heat loss.
>
> --
> The best argument against democracy is a five-minute
> conversation with the average voter.
>
> - Attributed to Winston Churchill
If you're listing issues.......
It depends on (in no particular order):
o where the heater is installed (how far it is from the farthest
faucet)
o how big the heater is
o the water usage pattern
better consider as well
o temperature of incoming water
o elevation (above sea level) of installation
if the incoming water is really cold (like sub 45) and / or
installation is in the higher elevations (like the mountains) forget
about a tankless
cheers
Bob
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