I just got a new water heater, replaced due to age (15 years) and
chronic sediment / rust. Both new and old were 40 gal (gas) and
thermostats were set to recommended temp setting. The only the other
thing that is different is a change to configuration of hot water
output pipes. And maybe this is the real cause... bear w/ me on some
Originally hot water was delivered from 2 places on the tank. 1 from
the top, the usual place. Also, oddly, from a pipe coming off the
*bottom* of the heater before the drain spigot. My guess is previous
owner thought it would be easier to add new service to this location
rather than trying to splice into the existing service to the tank. I
had my plumber just go ahead and cut/splice this service pipe to a T
junction at the top of the tank with the other service coming off the
top. In effect this shortened the service originally coming off the
bottom by ~ 5 feet max.
My house doesn't have a ready-hot water circulation system / pump
(which I understand involves this kind of second connection to the
So, I'm at a loss as to why it should take longer for water to get hot
@ shower. It is getting colder outside, but I live in San Francisco,
so the temperature really hasn't changed *that* much to make me think
it's the weather.
I suppose 1 explanation is thermostat on old was unreliable, heating
hotter than that prescribed by recommended setting on dial. Any other
ideas? The pipe splicing thing seems interesting too, though how
that'd cause it is beside me.
I would guess the old system used thermo siphoning to circulate the
water in the pipes using the fact that warm water is lighter than cold
giving you much the same results as using a pump.
You should save a little on energy cost, but as you have noticed it will
take longer for hot water.
-Hot water is never tapped from the bottom of the tank.
-99% chance this T connection to the bottom drain was the return leg of a
"thermosiphon" hot water circulation system which worked well w/o a pump.
firstname.lastname@example.org (HA HA Budys Here) wrote in message
Thanks. Well, that's got to explain it. What a cool trick (no pun
intended). My plumber spent time looking for a non-existent electric
circ pump, but didn't offer thermosiphon explanation. I have a
finished basement, so it's not possible to see all the pipes and I
incorrectly concluded, based on pipes going in different directions,
that they were serving different groups of destinations.
I suppose reconnecting to original spec incl flapper valve would be as
good as any for a first-time DIY plumbing repair if I decide I want
faster hot. I probably will - it worked pretty well!
I assume that if I have some sinks at basement level (ie, same level
as heater), they just won't get the fast hot from the thermosiphoning
I recently installed a new water heater in my house.
I installed the dielectric unions with the internal check valves. They
contain ball bearings of some sort which
is supposed to keep hot water from migrating out of the tank both at the
cold inlet and hot outlet when not in use.
With these installed, it now takes noticeably longer for hot water to get
to the destinations.
These do produce a kind of an annoying ratcheting noise at the water heater
when water is flowing.
Maybe your plumber installed something like these?
With the newer lo-flow fixtures, I'm a believer in reducing
the size of the supply lines from the water heater. Makes the
water in the line clear quicker, with faster delivery of hot water,
less wasted water.
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