Atwood Hot Water Drain Plug

Just replace the plastic plug with a full port plug valve and be done with it. Keep the plastic plug around in case you ever need it.

yankee camper wrote:
I know it's been discussed before but if the drain plug on an Atwood HWH is plastic so as not to create a metallurgic reaction to the aluminum tank then why doesn't the pressure relief valve or the thermostat coming off the gas valve cause the same reaction?

The Galvanic corrosion everyone is overly worried about is very low between aluminum, brass, bronze and copper. As you pointed out the gas valve and relief valves aren't plastic and cause no problem.

The big problem is with steel tanks where those metals react highly with steel and is why anode rods are needed with steel tanks.

The reason plastic plugs are used with the Atwood aluminum tanks is the plug is frequently removed by people wanting to drain the tank. If metal plugs were used, the aluminum threads can be easily damaged if you don't watch what you are doing. It is better to replace a damaged plastic plug than to have to repair damaged aluminum threads.

Whewwwww... Thank You , I should have offered a better description of my HWH right off the bat. Now it's making sense to me Thanks for not giving up on me!

Hey yankee camper

Didn't know you had a pilot gas water heater. I 'assumed' incorrectly you had a electronic spark.
Yes your thermostat rod sits in the water.

The gas valve screws into tank and the gas valve threads can get corroded due to the reaction between brass/aluminum and electrical current. And when removing the gas valve it will be tough to break loose. BUT just like the PRV neither are removed often.
Drain plugs are (should be) that is why they use the nylon ones. So that the frequent removal doesn't destroy the tank threads. Cheap to replace a nylon plug vs a tank.

The Electronic water heaters (spark electrodes) have t-stat/ECO that are button style that just make contact with tank wall

Different type of water heaters........different type of parts :B

Old-Biscuit wrote:
The PRV will......it's just that
1) it isn't removed as frequently as the drain plug should be
2) nobodies makes a plastic prv
3) Drain plug is nylon which can handle the pressure/temperature and will not destroy the drain plug threads when you remove it. They come in a 2 pack for a reason.

The thermostat just touches tank wall..not in contact with water.

Not looking for a pi**ing match here but in my first post I mentioned the thermostat and you thought I was confused with a gas line and said the thermostat doesn't come in contact with the water? I went to the Atwood web site and they called the "copper rod"the ECO. Now your picture says what I thought to be correct from the beginning? There is no doubt that you are far more knowledgeable than me with this stuff,that's why I post and ask (maybe dumb) questions, but I gotta admit I'm getting a little confused now. I didn't think you were being dismissive in you post, but if I was that in the dark mechanically I would not be attempting any of the work I have done on my rig. Thanks and hope you will be here in the future when I need help.

double post deleted

yankee camper wrote:
Bisquit,while I did not know the name of the ECO at the time, I do know what a gas line is.

Wasn't be dismissive......just couldn't visualize what you were referring too.

If you have a gas only water heater with temp adjustment control on gas valve then the rod sticking out the back of gas valve is the thermostat.
The gas valve screws into the tank and the thermostat rod is in the water.
The threads on gas valve can corrode/be difficult to remove.
Especially since (like the PRV) they are not removed very often.

Hi hogcard,

Yes. The smaller hole doesn't allow fast draining--which means that any sediment may stay behind and build up inside the water heater.

It also makes it hard to siphon out the water that is left in the bottom of the water heater.

It also makes using a flush wand hard.

I didn't know about this reaction thing you are referring to. I replaced my plastic plug with the metal one that has the center little helicopter valve you can open and close to drain the tank without removing the entire plug. An RV service guy actually recommended it. Any issues here?

Bisquit,while I did not know the name of the ECO at the time, I do know what a gas line is.