New Water Heater Drain Plug Won't Fit

[Kevin A]

Having read several posts about having spare water heater drain plugs due to plastic ones leaking, I ordered a new brass CAMCO 1/2" plug with a drain valve for our Atwood WH. This would replace the current plastic plug. However, when I tried to install it today, it would barely catch the threads and would not screw in at all. Since the plastic plug easily screws in, I didn't want to force this brass one. Is the thread configuration the problem even though both are 1/2"? Should I just stick with plastic and remove the whole plug to drain it? Curious...

[Raspy]

Go to any hardware store and get a 1/2" pipe plug. Then you'll know if the new one you have is defective or not.

I'm assuming the threads are 1/2" NPT and not 1/2" straight threads. The 1/2" straight thread plugs will have a flange that stops the plug and makes a seal, while the 1/2" NPT (National Pipe Thread) plugs are a tapered thread and a common plumbing part. 1/2" NPT is almost the same size, but won't screw into a 1/2" straight thread female fitting. The NPT ones are very common and can be found in cast iron, and brass at most hardware stores or at Home Depot.

The ones in my last two trailers were 3/4" NPT thread and included the anode. I screwed in a hose bib for easy draining.

[Kevin A]

Thanks. The brass plug from CAMCO via eTrailer just says 1/2", so I don't know if it is NPT or not. I'll try a couple plug fittings from the hardware store.

[mary and bob]

Take your new Camco plug into a hardware store and see if it will screw into a pipe cap or elbow or other female threaded piece. Since pipe thread is tapered the size may not be uniform from one piece to another depending on how far the tap or die was run into the hole or on the pipe. And if you have a foreign made plug, that may be the problem.

[steve dunham]

I tried using a pipe plug with a petcock drain valve . The petcock valve on my water heater would plug up constantly and then drain extremely slow or not at all
I finally gave up and went back to a 1/2 “ galvanized pipe plug

[Kevin A]

Thanks for the suggestions. Since Atwood recommends the nylon plugs, I guess I'll stay with those for now. They are cheap, haven't leaked yet in 3 years, and won't strip the internal threads.

[Darral T.]

Our local TSC (Tractor Supply Company) has MANY selections of the plastic plugs.

A lot of people do not realize you can use the teflon pipe tape and wrap around the plugs and it will seal them.


Here's also another source:
https://www.usplastic.com/search/?it...yword=%2462153

[Doug Arthurs]

I replaced the plug in mine with a small 1/8 ball valve. When I get hoe from a trip I open the valve and drain the water instead of letting it sit in there.

[Darral T.]

That's a good idea as well as I dont haul water in my wh. BUT, I do use the "Hottrod" so I remove it after every camping session (it may be used twice a year) and replace it with the cheapy nylon plugs.

Originally Posted by Doug Arthurs

I replaced the plug in mine with a small 1/8 ball valve. When I get hoe from a trip I open the valve and drain the water instead of letting it sit in there.

[Tug Hercules]

Just be cautious using anything other than the intended Nylon Plug.

Other metals set up galvanic corrosion issues with the SS Hot Water Tank threads; this may lead to not being able to then screw the Plug out, in the future.

[Casita Greg]

Originally Posted by Tug Hercules

Just be cautious using anything other than the intended Nylon Plug.

Other metals set up galvanic corrosion issues with the SS Hot Water Tank threads; this may lead to not being able to then screw the Plug out, in the future.

True that dissimilar metals can cause galvanic corrosion, but that said, whether you are using a plastic pipe plug, or a metallic pipe plug of the same thread, the reservoir water will have been drained after removing either the electric heating element, anode, or the "hot rod," (depending on the make and model of water heater you have.) Anyway, once you drain the water heater's reservoir tank, and there is no water in it, it really doesn't matter one iota what you use to plug it, whether it be plastic or metal. The bottom line is "No water - No corrosion." The water itself is the electrolyte which causes galvanic electrolysis. If the tank is empty it doesn't matter what you use.

[Tug Hercules]

Yes, but being a Hot Water Tank, it will have Water in it.

[Casita Greg]

Originally Posted by Tug Hercules

Yes, but being a Hot Water Tank, it will have Water in it.

How does the water stay in the tank when you pull the anode, electric element, or hot-rod, etc?

Removing any of these will result in the reservoir draining out, and you're certainly not going to heat the water, if there was any, without any of those critical devices installed, much less with a plastic plug screwed into it.

[Tug Hercules]

Yes, the tank will be emptied, when the drain valve is installed, however, the whole purpose of the original poster wanting to install some form of drain valve, in the outlet plug, is such that next time they want to empty the Tank, they can use the drain valve, to empty it. In the mean time, until next emptied, the tank will hold water, those resulting in a galvanic action in the threads, if dissimilar metals are used.

[MTRCYCMAN]

Originally Posted by Kevin A

Having read several posts about having spare water heater drain plugs due to plastic ones leaking, I ordered a new brass CAMCO 1/2" plug with a drain valve for our Atwood WH. This would replace the current plastic plug. However, when I tried to install it today, it would barely catch the threads and would not screw in at all. Since the plastic plug easily screws in, I didn't want to force this brass one. Is the thread configuration the problem even though both are 1/2"? Should I just stick with plastic and remove the whole plug to drain it? Curious...

I contacted Dometic (Atwood) recently about that exact question. They suggested to stay with the plastic due to corrosion of two metals. You might give them a call and get it straight from the manufacture.