I have determined that I have a blockage in the water heater that is restricting the hot water flow to the house. I believe it's a clogged/blocked nipple or heat trap. With all my strength, I cannot get the existing nipple to loosen. Do you have any suggestions to loosen the nipple? Maybe there is something to spray on and let sit to help loosen or do I just need to provide more leverage and strength. I didn't really want to pay a plumber to come out to just screw and unscrew a few nipples, but I may have no choice.

Spray some WD-40 let it soak for an hour and try, you also can use a little more leverage, good luck.

John

In addition to John's advice... Use as big pipe wrench as you can get your hands on. Bigger the wrench - the easier it will unscrew.

Heat the nipple with torch to loosen possible sealant on threads, then use pipe wrench. If nipple breaks use nipple extractor to remove broken piece.

Warning,

If you use the torch and use too much heat you may melt the dip tube and will cause you problem and you will have hot water problem, dip tubes are the same for electric and gas water heaters, see the image below, Thanks.

John