Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.
I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.
Can anyone here offer relevant experience or practice?
Dont you mean it runs off your boiler, what vents, the boiler or
heater, On my old pipes I would never let them get over 75, 150Lb ! I
think you are crazy to run it at all. The installer was a hack if it
actualy goes to 150lb. Whay do you even need 140f water, lower it now
to the lowest temp you need to take a hot water shower, with no cold
added. for me thats 95f, it will lower pressure before you break alot
of stuff. Pressure should not be more than incomming. Also you now run
the boiler to heat water in summer, likely that will cost you alot
more in summer.
Dont all dishwashers have electric heaters to bring the temp to what
is needed, mine does, whites, I use Bleach. No wonder this country
uses 25% of the worlds energy with only 5% of its population, nodody
cares about conservation. 140f is a waste, and if you really think
about where that hot water goes, down the drain. I keep mine around
100f in summer and my gas bill is still high.
PO's of my house were like that. I immediately turned the water temp up
so I could take a comfortable shower. Plus if you don't have it at
least 130F you can get nastiness growing in the water. I think before
the hot water was about 110F and I'd take a shower with all hot water
and it'd still feel cold - and then run out halfway.
Oh, and I have a solar tank feeding the gas heater, so I'm only heating
the water from maybe 90F to 130F not 65F to 130F - before you accuse me
of being wasteful.
replace "roosters" with "cox" to reply.
Many or most dishwashers have a "heat assist" to help maintain water
tempeature, but will not raise the temperature to correct operating levels.
Only some (usually high end) models have heaters with enough power to heat
(or preheat) the water to the correct operating temperature. Our
dishwasher is one with "heat assist". When we first moved into this house
(it was a new house), the water heater was set much lower than 140°. The
dishwasher was doing a really lousy job. When I increased the setting on
the hot water heater, the dishwasher's performance was superb.
In a prevous house we installed a high end, all bells and whistles
dishwasher which had water pre-heat cycles. We kept the water heater set
at a reasonably low temperature. The dishwasher performed flawlessly, but
because of the water heating cycle, the total operation time for a load of
dishes was well over 2 hours. In part, it depends on where you want to
spend your energy. I'm sure it wasn't exactly cheap for the heating
element in the dishwasher to preheat each batch of water to the correcct
temperature before running that part of the cycle.
We live in AZ where the incoming water is one the warm side most of the
year. Because of this, we also do not need a large water heater, nor are
ever having to raise 35-40° incoming water to proper temperatures. Ours is
only a 30 gallon quick recovery electric tank. I doubt seriously if we are
wasting a lot of energy.
We do have gas or oil service in our area, so electric was the only choice
Water expands when heated. Most water systems tend to be closed
(regulator, backflow check etc) and in a closed system it needs
someplace to expand so it is definitely standard practice to install an
expansion tank. Small house has nothing to do with it.
I presume you DON'T have anti-pipe knocking "water hammer" arresters on
your hot water piping.
Many DIY home improvement books show you how to make your own with copper
piping. Fun DIY project for long rainy weekend. Good training for
Commercial versions just for visual demo:
(click on link in write up for Water Hammer.
should be available at local BORG.
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