[SGVLUG] OT(TTM) Tankless Water Heater

[David Lawyer]

I'm currently installing a tankless.  This house originally had a
tankless in 1923 and it worked good.  It had a pan underneath to catch
the condensation water (the water vapor in the exhaust is converted to
liquid water by a counterflow heat exchanger so that the latent heat
of vaporization of the combustion water goes to heat the house water).
So I paid more and bought the latest condensing type water heater
since a year or so ago they rediscovered the 90-year-old condensation
technology.

I bought a Navien which is supposed to be 98 % efficient.  But I have
yet to hang it on the wall since I need to mount it in a corner and
the wall studs in the corner only have 3/4" of their edge directly
behind the plaster and the other 1 1/4" is inside the intersection of
the two walls.  I've finally figured out how to do it by putting
screws in at an angle, etc.

Our hose has a 1 1/4 " main gas line and used to have a notice near
the meter not to restrict the flow.  But both the meter and the 1/2"
connector piping that was installed near the meter restrict the flow
so the gas co. is coming out to install a larger meter and hopefully
larger piping near the meter. 

This water heater has both water pipe nipples and a gas line nipple on
the bottom, all at the same distance from the wall.  This is going to
make it hard to connect it up using rigid pipe since pipes need to
cross over each other and two of these must go the pipes that enter
the house area on an adjacent wall.  So I may have to resort to using
flexible tubing for both gas and water.

When I bought it they tried to sell me a $70 installation kit which
makes it easy to use vinegar to flush out the unit every year or so.
I was incorrectly told that the guarantee requires that this be done.
But the manufacturer's rep say not so and that the calcium in Pasadena
water shouldn't stick much to the stainless steel heat exchanger
(which is guaranteed 15 years).

So I'm glad to see this house revert to it's original type of water
heater, but how well it will work out is something I don't know yet.
One ominous sign is that the instructions say the holes drilled on the
mounting bracket are 16" apart for 16" stud spacing.  I got one with
15 1/2" spacing and was told that I'm the first one to complain to the
local rep. about this.  So thus far it doesn't look that great.

Another problem is the rebate (indirectly from the gas co.)  They
state that it must be installed by a contractor, but I'm going to list
myself as the "contractor", have it inspected by the city, and claim
a $200 rebate.  The rep. thought that should be OK but ...

			David Lawyer