Water Heater Element thread fit

[JimEb]

Do water heater elements normally thread in tight on the last few turns?

I have two 1” NPT half couplings that I plan to weld onto my kettles. Noticed by hand fitting I could barely get a turn of engagement between the 1” NPSM heating elements and the 1” NPT couplings. I managed to access a 1” NPSM plug tap so I chased the threads on the couplings. They fit much better now, but still tighten up before the seal makes contact. I’m not sure if this is normal in order so that the element won’t loosen up after being snugged up with a wrench. Or if I need to relieve the lead in on the couplings so that the element easily thread fully on.

I need to make sure the couplings are right before I they get welded to the kettles.

 

[quantrellc]

Water heater elements are a straight thread and your npt coupler has tapered threads so they will go together hard, so if you are having your fittings welded on I would try to find a straight threaded coupler I believe they are referred to as nps

 

[JimEb]

Maybe instead of saying 'chased' I should have said 'rethreaded'. I ran a straight thread tap through each fitting so they are no longer tapered threads.

There seems to be some imperfect/incomplete threads on the water heater element. I'm debating if this is per design (to lock the element in) or if I should relief the threads in the couplings to accomodate.

So to go off other people's experiences, are you normally able to thread them on by hand all the way to the seal?

 

[quantrellc]

I did almost the same thing as you, I had npt couplers and the elements threaded in very hard so I ended up ordering a weldless nps set up and the element treads easily into it and then just snug it down onto the seal. Hope this helps

 

[JimEb]

I did almost the same thing as you, I had npt couplers and the elements threaded in very hard so I ended up ordering a weldless nps set up and the element treads easily into it and then just snug it down onto the seal. Hope this helps

Thanks! Exactly the info I was looking for. I'll tweak the thread lead-in and minor diameter to allow the element to easily thread on.