water heater issue

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

baldrudy

Member
Joined
Apr 24, 2022
Posts
6
Location
ohio
I drained the hot water tank and when I went to reinstall the anode rod the threads are rusty and very hard to get it back in. Can I use a tap and die set to clean the threads and what size do I need to buy?
 

Jbuck

New member
Joined
Jun 27, 2022
Posts
3
Location
Mt. Erie, IL.
I cannot help with size, but I ran a tap through mine, and it cleaned them up really nicely. I took my old anode rod to compare the thread pitch and size when I borrowed a tap. Good Luck
 

Kirk

Well-known member
Joined
Oct 30, 2005
Posts
3,358
Location
Full-time , Escapee
Is that the hex size? OP needs the thread size.
You are right. I gave the socket sizes. the actual opening size is 1/2" on the Atwood and it is 3/4" opening on a Suburban, I believe.

Baldrudy, if you are not sure, get a bolt of the size that I am suggesting and see if you can hand thread it into the drain opening, or take the drain plug to a hardware store and try their nuts on it.
 

Rene T

Site Team
Joined
May 20, 2011
Posts
19,783
Location
Farmington NH
You are right. I gave the socket sizes. the actual opening size is 1/2" on the Atwood and it is 3/4" opening on a Suburban, I believe.

Baldrudy, if you are not sure, get a bolt of the size that I am suggesting and see if you can hand thread it into the drain opening, or take the drain plug to a hardware store and try their nuts on it.
NOOOO! Don’t wind a bolt in that hole. If you do you’ll be looking for a new heater. The threads are tapered. They should be a pipe thread not a straight thread.

The Suburban will take a 3/4” NPT tap and the Atwood will need a 1/2” NPT tap. NPT stands go national pipe thread. Don’t remove any material with the tap. Just clean the threads.

I think the problem you are having is the anode is fully into the tank and it’s difficult to straighten it to get it to start. Keep playing with it until you get the correct angle. You shouldn’t need to tap the hole.
 
Last edited:

JayArr

Well-known member
Joined
Jun 13, 2020
Posts
1,421
Location
Mission British Columbia Canada
Wait a minute, something is off here. My Atwood tank is aluminum and aluminum doesn't rust.

Is your tank steel? Are the Suburban tanks steel?

Can you give us a make and model? Maybe a picture?
 

Kirk

Well-known member
Joined
Oct 30, 2005
Posts
3,358
Location
Full-time , Escapee
NOOOO! Don’t wind a bolt in that hole. If you do you’ll be looking for a new heater. The threads are tapered. They should be a pipe thread not a straight thread.
Correct so do not use any type of tool. It won't go in far but just enough to measure diameter. I have done that more than once.
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
76,598
Location
West Palm Beach, FL
He stated that he couldn't get the anode to thread in, so presumably this is a Suburban heater. And yes, it is pipe (tapered) thread. According to this article, Suburban uses 3/4" NPT at 12 threads/inch

Taps designed for cleaning (chasing) existing threads are available at Home Depot, Lowes and many hardware stores. Use only hand-power and don't force it.
 

JayArr

Well-known member
Joined
Jun 13, 2020
Posts
1,421
Location
Mission British Columbia Canada
To the OP: Make sure it is a NPT tap or chaser (for cleaning).

I own a couple of sets of thread chaser/cleaners and none of them are NPT, they are all straight thread. In fact, I've never seen a NPT chaser set.

Cleaning the thread with a regular chaser or tap will take the taper out and the anode will fit real easy but will have an increased chance of leaking.
 

Jim18655

Well-known member
Joined
Nov 27, 2017
Posts
241
I would try a wire brush of the proper size made for cleaning copper pipe fittings. Just insert and spin a few times to remove the corrosion. A few times on the anode threads would also help.
 

baldrudy

Member
Joined
Apr 24, 2022
Posts
6
Location
ohio
Thanks for the suggestions. It does take a 1 and 1/16 wrench to take it out. I am hoping to get to the camper this weekend to get more info and see what I can do with it.
 
Top Bottom