[VAC] tankless water heaters - more

[Robert C Townsend <rctowns@xxxxxxxxxxxxx>]

As I understand it, the compressed air and demand pump systems both maintain
around 35 psi... a good question and an important consideration, though...
however, for the kinds of hot-water use for which the tankless systems are
'best', i.e. 'unlimited hot water', a city-water supply would clearly be the
preferable source. In 'boondocking' situations - where one's water supply is
necessarily limited to what one carries with - the traditional small propane
fired systems seem more suitable for 'navy showers', since the initial cool
water is that which is in the hot-water line between faucet and heater...
the tankless systems take a few extra seconds (pints? gallons?) to get the
water flowing through it up to temperature....

re: 'venting' natural gas/propane tankless heaters:
venting up a lined chimney (which usually requires a vent fan, too) is only
necessary if the distance to the vent outlet is greater than 10 - 15 feet,
or something on that order. the Takagi (i don't work for them, honest) i
installed has a vent run less than five feet to an outside wall of the
garage, and only about a foot of vent-height above the heater (an important
factor). If i were to use a tankless heater for maximum effect, i'd put the
rolls-royce of tankless heaters (the 'Mobius' TM-1) for about $2,000... and
get the 8.3 gpm rate. In a boondock situation, a nice hot, high pressure
shower would go through my week's supply in a couple of minutes...unless i
set up the SofTub as a rainwater collector/cistern, or ran a suction line
over to the nearest river/stream/creek...

Tuna