water heater plastic plug removal

[Notakwanon]

With the weather forecasters saying the temperature here in MD will drop to 19 tomorrow night, today I decided it was time to drain water from the Outfitter Apex camper. I grabbed the head of the plastic plug at the bottom of the water heater with a channel lock, as I have before, tried to turn a little, and the head of the plug snapped off. Well, that solved the problem of water removal, but now I've got plastic threads that somehow have to be removed. The space to get in there is very tight. Is there a better method for tackling this repair than to remove the burner unit, just to get at the drain plug?
Tom McCloud

[Kayteg1]

Some people install water accumulators in RV to lower pump fluctuation and also to have some pressure for midnight pee without waking up family with rattling pump.
I have the same benefit without the accumulator.
I think the primary function of air bubble in small rv system is to lower pressure build up when the burner comes on. Otherwise you will see PRV dripping during warm-up period.
Not that building system pressure to 150 psi is a good thing.

[covered_wagon]

The PRV is located on the outside on all water heaters is standard safety with the same as a house HWH, it is the same PRV. Your saying because of the outlet being lower than the top there is an air bubble that in essence can never be purged. You do have to purge up to that point though otherwise you can crack the tank if turning on prematurely. The air bubble you speak of does not negate the need for the pressure relief valve. That is all I was trying to say.

Sorry for the confusion.... I should have been more clear on that.

[Kayteg1]

Again, that applies to RV WH as household WH have different principals.
As you can see on the pictures, the hot water outlet on RV heater is placed some distance from the top, what keeps air bubble.

[covered_wagon]

I don't understand what you are doing for an air bubble nor why doing such a thing is needed, I have been around great plumbers for many years and always do as the plumbers do and that is to turn on the water pressure with the hot side open on the faucet till all the air is purged out and the water flows solid. Then you can turn on the water heater if needed. you want no air in the HWH as the pressure relief valve takes care of the safety aspect. They are the same PRV that is on house HWH'rs as well. I wonder sometimes why I even try educating people on these forums as it seems opinions are becoming solid knowledge now a days

[Kayteg1]

Each WH has safety valve. I think those in RV are only pressure valves, when household WH has pressure/temp safety valve.
Still I would not count on plastic plug design to work with 150 psi pressure to be much of safety relieve.
BTW WH in RV are design to have air bubble on the top not only for safety but also for convenience. The air with time gets sucked by water what you can notice by pump making big fluctuation with drizzling faucet.
How many ever tried to restore the air bubble?
For me it becomes routine that when I hook up empty hose to my camper, I open hot water faucet so the air from the hose runs via WH restoring the air bubble.

[enblethen]

HMS Beagle
That is what I was told many years ago along with acting like a freeze plug.

[HMS_Beagle]

I was under the impression that the plastic plug is a safety device - intended to soften and/or blow out in the event of overtemp/overpressure. Replacing it with a metal one will defeat that purpose.

[Kayteg1]

In my home repair business I made quite nice chunk of money replacing galvanized nipples put into copper plumbing.
For housing developer saving $2 on a nipple multiply by 12 nipples in the house, multiplied by 200 houses made it worth the risk - especially that the electrocorrosion acts slowly and usually the nipple start spraying water after 15 years.
But it is unavoidable.

[Bumpyroad]

I have a brass plug that has a built in petcock to drain.
bumpy

[beachbum2011]

Once you get the plastic plug removed, eliminate the problem with a trip to hardware store
Add a ball valve to drain hot water tank. Used this setup on last two campers with no issues.

[NMDriver]

I have used a galvanized steel plug for 10 years. Just use plenty of teflon tape. I also use a closet wrench to remove and put in the plug. A closet wrench will go past the propane feed tube and grip the plug without any problems.

[covered_wagon]

I think a SS plug could be had on special order from a plumbing supply house. They need them for plumbing that carries chemicals or for beer breweries that use all stainless pipeing.

I am interested about those aluminum tanks... I would like to take a magnet to the female threads to see if they are aluminum or steel.

Kayteg, interesting post BTW.

[Kayteg1]

Aluminium does not corrode with water, but is very prone to electrocorossion, so those tanks do require quite different maintenance than steel tanks.
SS plug might be good solution, but try to find one.
Coming to plastic quality - I noticed technological set back in the industry similar to automotive batteries.
Driving Mercedes, those build in 1980's had plastics that still holds today. Beside interior, window sliders, transmission switches from those years do work after 30 years.
Now after year 2000, stupid rubber groomets tend to turn into dust after just few years of use.
I come to the point that when I need rubber or plastic part for 2008 car, I go to junk yard and pull the same part from 1980's model as that one will last.

[covered_wagon]

Kayteg1 wrote:
OP has aluminium tank that don't use anode.

Yes, but an anode that is a metal being less noble than the aluminum will take up most all the corrosion cause by unlike metals i.e. brass plug and aluminum tank. In essence will eat away at the anode instead of the tank.

Another option is to go to a stainless steel plug which is known to do well with aluminum.

I wonder, are the female threads on those tanks aluminum or is it a pressed in adapter, possibly being steel? If aluminum threads, One needs to be very careful not to over tighten.

Im thinking the plastic plugs are a problem since heat from the water heater starts breaking down the plastic causing it to become brittle.

There are better grades of plastics that can take heat better over time, but you would have to research the correct type of plastic and then have a plug milled on a lathe.

It's amazing how much research on the net will reveal the wrong answer over and over. For example, trying to find the correct type of glass for an oven door, every search reported using tempered glass, but was very wrong as an oven door needs ceramic glass like that on a woodstove.