Pressure damaged water heater and options

Dean_12

Wow...thanks...

So by this it looks like sticking with oil is probably the way to go. And by running the incoming cold water through a coil in the boiler, I'd essentially be using the heater as a holding tank for boiler-heated hot water. I'd assume wintertime losses within the boiler would be offset by savings within the heater...proving that out would be something I'd need to research. I'd assume I'd have to mix coil output with cold water before the tank, too.

This (kinda) sounds like fun!

Dean_12

The temperature/pressure relief valve on our oil-fired hot water heater doused our floor last week, so I went out and purchased a new one (the old one was obstructed by sediment, wouldn't close), flushed the tank and installed it. Fired up the burner and the new valve vents just as the thermostat cut out.

Grabbed a water line pressure gauge and the heater is popping up to 150+ psi.

Looking at the tank, I realized what I thought was a shoddy installation is really evidence that this tank has seen better days. See attached.

The top of the tank has collapsed due to the concave bottom bulging out from high pressure, and the central flue has pulled down the top, making the nipples turn inward. This tank has seen some pretty high pressures.

Since water cannot be compresed, the only place for water to go is out the cold water supply. Seems my water meter has a check valve that does not allow water to flow backwards and as such has spelled doom for my water heater. Guess I need an expansion tank or some such.

So...long story short...I need a new water heater. Given that I'm currently set up for oil-fired (burner is about 10 years old), but have gas and electricity available...which would you go with? I also could tap into a hot water coil in my boiler...maybe even just to warm up the incoming water to my tank. What would you do? I'm much more intersted in total cost of operation versus what it costs me now...

John Starcher_4

Best bang for your buck.....

...depends on your fuel costs.

Around here, (as of today :-0) natural gas is running about $1.50 to $1.60 a therm. Electric is double, Oil and LP are somewhere in between.

Starch

Paul Pollets

You need...

...a pressure reducing valve on the CW main that limits house pressure to 70PSI max. 50PSI is preferred. Any water tank will be damaged, as well as the plumbing fittings, by high water pressure. Very risky stuff....call a professional if you don't have the skillset to install a PRV.

I'd be installing an indirect water tank with the boiler and a control that manages both boiler and water tank priorities. Viessmann makes the best indirect tanks (and the most expensive).

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Dean_12

Incoming pressure is about 60, so yes...I'll be adding a reducer on there if my 3rd floor pressures are sufficient. I'm also supplying a rental house about 80 feet from my back door, so I have to be careful where and what I drop.

Mike E_2

It all depends on energy prices in your area.

Prices by me are

gas - 1.30/therm

propane - 1.70/gal

oil - 2.21/gal

elec. - 0.08/KWH


Gas and propane water heaters have an energy factor between .5 - .6

Oil water heaters have an energy factor of .8

Electric water heaters have an energy factor of around .95 (although if the heater in in a conditioned space, it is 1.0)


So for me the prices work out to be for 100,000 BTU of usable heat:

gas - $2.32

propane - $3.31

oil - $1.97

electric - $2.41


Here's the equation to use your own prices -
(100000/energy factor) / BTU per unit of fuel * price per unit of fuel

example for gas:
100000 / .56 / 100000 * 1.30 = 2.32

Michael

Greig

Look at the Rinnai on demand water heater. $300.00 tax credit for 2006. Mount on outside wall using the Horz vent kit. Engery factor around .8 They work really well.