Thread and Pitch

Roland_18

Hi All,

A quick question, what is the thread size and pitch of the element tappings in an electric water heater? Where would I get fittings to interface with said element tappings?

Thanks, Roland

icesailor

Treads:

water heater elements are standard 1" IPS threads. A 1" screw plug will fit in.

Why do you ask?

If you are trying to use the taps for a side-arm heater arrangement to feed a floor panel or something like that, you can do it but it is very hard on the tank.

IMO

Charlie from wmass

I am guessing

It will be used as a storage tank. I thought the thread was 1" NPS as in straight thread which is why they use a gasket. Lots of Teflon tape needs to be used to make the joint water tight.

Roland_18

Thread and Pitch

Yes, it will be used as a storage tank for hot (160*F) water. I understand that there will be thermal stress on the tank due to heating/cooling cycles.

Roland_18

Thread and Pitch

Yes, it will be used as a storage tank for hot (160*F) water. I understand that there will be thermal stress on the tank due to heating/cooling cycles.

Charlie from wmass

many people use

1" NPT into the element ports, when I have done this I used 6" long brass nipples and Loctite thread sealant, the stuff that looks like dental floss.

Roland_18

Thread and Pitch

Thank you to all who have responded to my question.            Roland.........



Just out of curiosity, do 1" NPT to IPS fittings exist?

Charlie from wmass

IPS is

Iron pipe size which is the same for NPT or NPS. IPS is in regards to the diameter of the out side of the pipe. NPT is National pipe taper and NPS is National Pipe Straight for the geometry of the pipe threads.

hot_rod

the element

depends on a rubber ring gasket to seal. I don't believe that is a tapered thread in the tank?



The was a fitting available to convert the old 4 bolt elements into a screw type 1" FIP thread.



I have screwed into the tank holes before, but I'm not sure it is a "factory approved' method of connection.



hr

Roland_18

Thread and Pitch

I was perusing the I/O manual of a Kenmore water heater, and it shows the expansion tank on the COLD water side. Why is this? Do we need one on the HOT side as well?

Charlie from wmass

The water will push back to

the cold side. It is for domestic water production especially if there is any sort of check valve on the supply. They put it on the cold side so it will last longer. No you do not need one on the hot side also.

Hot Rod, I do not believe it is a factory approved method to screw into the element opening and may void the warranty. I have done it in the past myself but I was not concerned with the warranty. I first saw this done with System 200 installs through out Berkshire county, MA. I am not sure if installers in other areas also do this? Guys do you?

icesailor

THREAD, PITCH AND TANK OPENINGS:

Charlie,

If you buy a John Wood hot water storage tank (like the plumber who plumbed the last house I built where I live), it is just a stock 50 gallon electric hot water heater with 1" plugs screwed into the tank. There is some small amount of taper to the female threads in the tank. The gasket you speak of is really for the shoulder/flange of a water heater element. When I use electric water heaters for hot water storage tanks, I just leave the electric elements in place. I've probably installed at least 75 of them and I've never had one leak through the element. When they go, they go like any other water heater.

I didn't plumb or heat this house I built in 2001 because the contractor hired all the subs and the plumber/heater was a good guy. I was busy working for my regular customers, where I work.

Three wraps of Teflon Tape, especially the new "Blue Monster" stuff and Hercules Meg-Loc Blue or Rectorseal #100 Virgin Teflon Paste is all I ever use. I've never ever had a leak. I also use Rectorseal #5 with Teflon Tape with it.