Tankless water heaters?

[K Frame]

The air rising will constantly cool the water...I didn't say it ready the tempurature of the air.

Ah, gotcha.

That's why some new gas water heaters have dampers in the exhaust. To keep that from happening.

[Brad Johnson]

They also have little flapper valves in the water fittings to keep heat from migrating out of the tank via the water.  Such clever chaps, these engineers...

Brad

[K Frame]

They also have little flapper valves in the water fittings to keep heat from migrating out of the tank via the water.  Such clever chaps, these engineers...

Brad

Di-electric heat trap nipples.

They actually aren't little flappers, they're two little balls.

[Brad Johnson]

The ones on my last WH (installed in November) were tiny little rubber/neoprene flaps that just stuck out into the connection.  They like like a check ball or anything.  They ... well ... they just stuck out there and flapped in the water flow.  They didn't even seal to the edges.

Brad

[K Frame]

Damn. That's a new design.

[grampster]

I needed more hot water because we installed a whirlpool tub.  We had a 30 gal quick recovery gas  heater.  I discovered that if I wanted a larger gas heater, 60 or 70 gallon, I'd have to install a blower unit to disperse the exhaust.  So I purchased a 30 gal electric water heater in series.  Cold water goes to the gas heater first then to the electric one.  The gas heater is more efficient and cheaper than electric to heat cold water.  The electric heater stores the hot water and as you use that water it is replaced by hot water.  My gas bill went down a bit as I don't always use all of the hot water from the electric heater so less cold water is heated.  My electric bill went down a bit because with an electric heater, the power company gave me a lower rate on electricity.

[Brad Johnson]

After thinking about it for a bit I can see the logic of the design.  Even thought the little flaps don't seal anything, they do serve as a heat barrier.  The flaps intrude into the water stream (I'm guesstimating) about 80-85%, meaning that if they were fixed in place they would provide about an 85% blockage of the pipe.  The only water/water contact is around the edges thus the only place where the heat can be directly transmitted through the water is this small area.

What doesn't make sense to me is they are installing all this paraphernalia in a copper pipe.  Looks like the copper, being a darn efficient heat conductor, would carry away far more heat than the water.  Why don't they put some kind of heat-resistant joint on the heater so that you don't have direct contact with the copper piping?  Hmmm... something to ponder.

I can just see one of those little flappers either getting scaled up from our hard water or coming lose and getting stuck in something (which is why the little flappers ended up in the trashcan).

Brad

[mtnbkr]

Damn. That's a new design.

They existed back when we did my water heater.  I recall seeing them.

Chris

[K Frame]

Damn. That's a new design.

They existed back when we did my water heater.  I recall seeing them.

Chris

I don't recall seeing them when we were getting the stuff we needed. I sought out the di-electric heat trap nipples because your old one had a serious case of electro-rot around that one pipe set.

Maybe it's the di-electric part that has something to do with it?

These are very similar to the ones I put on your water heater...

[mtnbkr]

Maybe the ones I saw were online when I was reading up on the replacement process.  Either way, they existed back then.

Chris

[280plus]

Natural gas is the cheapest type of fuel if available.

Last time I figured it oil was more efficient/cheaper than nat gas. I haven't done the numbers lately but when comparing high efficiency gas boilers to high efficiency oil boilers the last time it became necessary the oil won out.

You need to compare the price in your area between a "therm" of gas which is 100 Cu Ft x 1000 BTU per cu ft or 100,000 BTU and a gallon of oil which is 140,000 BTU. The best (conventional) gas efficiency available right now is 93% the best oil efficiency is 86% so if you take 100,000 BTU and multiply it by .93 you get 93,000 BTU of usable heat to your house from gas, if you take 140,000 and multiply it by .86 you get 120,400 BTU of usable heat to your house. And that's what it's all about. Propane is even less efficient than nat gas as it has less BTU per cubic ft than nat gas.

[gunsmith]

I used them in Ireland, once you get used to the extra nobs and dials they're pretty good.