When replacing a water heater,do you have to put a washer/gasket above the iron nipples coming out the top of the tank?

The gas water heater tank I replaced is >15-20 years old. The Brand New Water heater I bought doesn't have instructions. Do I need to put a washer/gasket where the iron nipples/ short iron pips come out the top of the tank and meet the corrugated Copper pipe? It is was too corroded to tell if one was there in the past or not. Most any advice greatly appreciated.
Of note, the short iron pipes are already connected to the water heater and they have some kind of "Dielectric??" plastic protector on it. Will this make a washer unnecessary?
Thanks Greatly
RONIN
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replace the flexible hot and cold connectors with new ones. just use teflon tape for leaks as usual. a dielectric union is used when copper meets galvanized to avoid corrosion at that point.
and "4. Wrap the threads of the heat trap fittings with pipe-wrap tape, and screw the fittings into the water heater (blue into the cold-water inlet, red into the hot-water outlet). Be sure the arrows marked on the fittings point in the direction of water flow. 5. Install new flexible connectors on the water inlet and outlet pipes. If there is no shutoff valve on the cold-water side, install one before connecting the water heater. After all connections are complete, open the shutoff valve to fill the tank. While it is filling, open several hot-water faucets in the house to bleed off air in the pipes." story and photos at: http://www.hometips.com/articles/replace_waterheater.html and excellent info about troubleshooting hot water tanks at: http://www.waterheaterrescue.com/pages/WHRpages/English/Longevity/water-heater-basics.html
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DO NOT sweat solder copper pipe to fittings with connector screwed on tank, you will ruin the dip tube and probably will have a poor connection anyway.
sweat the fittings to at least 6 inches of pipe, cool, screw on tank after cutting and use connector.
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In canada (who cares about the rest of the world, we are taking over) you must install a new dielectric union at each and ever point where iron or galvanized meets copper. /brass. Not required at pex connections.

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Thank you and the others who answered my questions. I did use Teflon and no gasket. I think the dielectric device served that function. I used soapy water to test for gas leaks and didn't see any bubbles though I did get a whiff of gas ( this was true of the old tank as well.) How big would the bubbles be - noticeable right?/ Thanks again
Ronin
On 12 Feb. 2006 00:54:03 -0800, "buffalo bill"

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On 2/13/06 12:57 AM, in article snipped-for-privacy@4ax.com,

Bubbles would be most noticeable. Double check/tighten every fitting and check for smells after the unit has finished heating one cycle. If you still smell gas, you may still have a leak.
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wrote:

Try taking a lit match or lighter around each connection and see if the flame sputters.
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