Suburban water heater anode threads

[PbMax1972]

Has anyone had to redo the female threads on the Suburban water heater where the anode goes. I had a hard time getting the anode rod to catch and screw in last time out but got it in. Drain everything last time we came in because we knew it would be a while before we got back out. Can’t get threads to quite catch, it almost grabs then pops out. I’m thinking the female threads in the tank are buggered. Has anyone tried to retap this and if so what size? I’m thinking it needs a 3/4” NPT tap to clean the threads and get then straight again? Thoughts on correct size?

I always use a thin lapping of Teflon tape and keep it back from front edge of the threads of the anode so it can get a bite and start in before it gets to the tape.

Thanks

[Javi]

If you use an actual tap be very careful not to remove metal... just screw it in far enough to clean out the old tape and rust but not metal...

[KimNTerry]

try a brass wire brush as well. Just clean up to remove old tape/dope/crud

[Weekender 1]

3/4 NPT is correct.
And you can go in just enough to remove a small amount of metal to correct the thread.

Aluminum has a tendency to gull, so make sure you use some light oil on the tap.

[bobbecky]

If he’s cleaning up threads for the anode, he is cleaning up steel threads. On an Atwood heater, that is aluminum and does not use an anode. The Suburban tank is all steel and that is where the anode is used.

[travelin texans]

Had the same problem, chased the threads & still difficult to start 1srt few threads, then I tried holding the rod with a pair of pliers & stabbing in straight in & twisting a couple threads no more problems starts 1st time every time.

[JRTJH]

Keep in mind that the threads are "tapered". I can't tell you is it's the threads in the water heater or the threads on the anode rod fitting, but they are not "level and even"... The anode rod will only thread into the fitting 4 or 5 turns before it "tightens and won't turn"....

IF (again, I don't know which part or if both are tapered) you run a tap through the fitting, you may run into problems with leakage, assuming that the fitting is tapered rather than the anode shoulder threads.

[Javi]

Originally Posted by JRTJH

Keep in mind that the threads are "tapered". I can't tell you is it's the threads in the water heater or the threads on the anode rod fitting, but they are not "level and even"... The anode rod will only thread into the fitting 4 or 5 turns before it "tightens and won't turn"....

IF (again, I don't know which part or if both are tapered) you run a tap through the fitting, you may run into problems with leakage, assuming that the fitting is tapered rather than the anode shoulder threads.

Both are threaded NPT... which is tapered..

[hankpage]

The weight of the anode tends to pull down and cause an uneven start. A wire brush made for cleaning 3/4" copper pipe fittings works the best for cleaning the female threads of the heater and once clean you should see if they are buggered and the threads need to be chased. Insert the rod and press tightly in place with your left thumb, you should feel the rod tip up, start the threads with your right hand while still maintaining pressure with your left. ( you can get the same effect with a tight six sided deep socket to tip the anode up while turning without ratchet attached. ) If you're a lefty, I guess you can reverse the position of your hand and thumb. JM2¢, Hank