Hot water heater drain modification.

[Jagiven]

Originally Posted by Johnynorthland

in regards to plastics tanks, ones without anode rods, do they scale as much as the metal ones? I’m on my 3rd RV and never noticed anything draining out of the tank other than water.

I have not physically looked inside my tank (I do have an endoscope). I have not noticed any scale when I have drained and flushed.

I do not have a wand that you can insert in the drain port to flush the tank. I flush the tank, via splashing water into the bottom of the tank via the upper outlet. I will shut the lower cold water inlet valve, open both the bypass and the hot water valve open, along with the tank drain. Turn on the water. The water will back flow into the tank from the upper hot water port, and let it splash, and drain. When done, I have never noticed any scale on my driveway.

[Bob K]

I've added a drain valve, too, since I drain often. I discovered, too, that my low point drains will also drain the hot water tank, so that's a nice option.

https://www.amazon.com/gp/product/B07GWBK57V


Yes, that's a stainless steel valve threaded directly into my aluminum tank.

I'm going to take one for the team here and do a little galvanic corrosion experiment. SS316 and aluminum are only .5 volts apart on the anodic index, and this isn't salt water. Additionally, the aluminum tank is a huge anode as compared to the in-contact portion of the relatively tiny stainless steel valve (cathode). I'm going to check the tank, tank threads, and valve at regular intervals to see just how much galvanic corrosion is actually taking place. My hypothesis is that the tank and valve will long outlast the rest of the trailer. I'm ready for the little experiment to prove me right or wrong.

[Lake Huron]

It's funny you say you took a pic with your phone, because that's exactly what I did with my vin/weight stickers on the side of the trailer. They are fading as well. I'm going to have new ones made up and place them where they wont be exposed to the fading sun. And then probably peel the old ones off the side of the trailer.

[Jagiven]

Originally Posted by Bob K

I've added a drain valve, too, since I drain often. I discovered, too, that my low point drains will also drain the hot water tank, so that's a nice option.

https://www.amazon.com/gp/product/B07GWBK57V
Attachment 65359

Yes, that's a stainless steel valve threaded directly into my aluminum tank.

I'm going to take one for the team here and do a little galvanic corrosion experiment. SS316 and aluminum are only .5 volts apart on the anodic index, and this isn't salt water. Additionally, the aluminum tank is a huge anode as compared to the in-contact portion of the relatively tiny stainless steel valve (cathode). I'm going to check the tank, tank threads, and valve at regular intervals to see just how much galvanic corrosion is actually taking place. My hypothesis is that the tank and valve will long outlast the rest of the trailer. I'm ready for the little experiment to prove me right or wrong.

I installed, if I recall correctly a brass pipe nipple (TT is in storage), in my tank drain. Everyone on the forum said do not do it. Before I did it, I first spoke with a metallurgist at work, and he said I would have no issues. Just about 9 years later and there is no visible signs of galvanic corrosion. So I would not worry about it.

[Bob K]

Originally Posted by Jagiven

I installed, if I recall correctly a brass pipe nipple (TT is in storage), in my tank drain. Everyone on the forum said do not do it. Before I did it, I first spoke with a metallurgist at work, and he said I would have no issues. Just about 9 years later and there is no visible signs of galvanic corrosion. So I would not worry about it.

Great data point. Thanks! Important to note, too, that brass is even more cathodic (ie. prone to cause more galvanic corrosion with aluminum) than stainless steel.

[Bob K]

Originally Posted by Lake Huron

It's funny you say you took a pic with your phone, because that's exactly what I did with my vin/weight stickers on the side of the trailer. They are fading as well. I'm going to have new ones made up and place them where they wont be exposed to the fading sun. And then probably peel the old ones off the side of the trailer.

Excellent tip. I just walked outside and took the same pictures.

[Bayoutalker]

Originally Posted by Rustic Eagle

Good question.....

The advantage for me is that I take numerous trips during the course of the year and drain my HWH tank between them.

When winterizing annually I remove the stainless tubing/valve as an assembly and flush....., same as removing the prior plastic drain plug.

Bob

Why do you drain after each trip? I've never heard anyone else doing that? Also, are you using an anode? My anode replaces the drain plug and there is no hole in it.

[Rustic Eagle]

Originally Posted by Bayoutalker

Why do you drain after each trip? I've never heard anyone else doing that? Also, are you using an anode? My anode replaces the drain plug and there is no hole in it.

Depending on the original source of the water and how long the water sits in the HWH tank while in storage between trips, the "re-heating" of the same water can create a smell (been there, done it).

I have an Atwood HWH with an "aluminum" tank which doesn't require an anode rod, the Suburban "steel" HWH tank requires one.

Bob

[ggilbert]

I use only this valve on my heater. No extension hoses. And I have no problem. I also put a 90 degree bend on the lever to make it easier to turn with obstruction

Litorange 2 PCS Heavy Duty Brass... https://www.amazon.com/dp/B07Q12XG5N...p_mob_ap_share

[Kozmo]

My situation is, if I don't drain the HW tank, the next trip I start with the sulfur smell. By starting with fresh water, I don't have the horrible smell.

[cherv]

Hi, love it, plan on doing mod. WINTERIZING. WHEN I drain the hw tank there is still some water left so i use a turkey baster with plastic extension tube attached to suck out residual water. Any issue leaving water in during winter??

[Farmerfred]

I thought the relief valve was pressure- temperature with a probe going into the tank. Pipe it away from the tank and you lose the temperature safety part of the valve. Just my 2cents.

[Bayoutalker]

Originally Posted by Rustic Eagle

Depending on the original source of the water and how long the water sits in the HWH tank while in storage between trips, the "re-heating" of the same water can create a smell (been there, done it).

I have an Atwood HWH with an "aluminum" tank which doesn't require an anode rod, the Suburban "steel" HWH tank requires one.

Bob

You better rethink that one. The aluminum tank definitely needs an anode. I had to replace my tank earlier this summer due to corrosion. I spoke to a friend in the RV business and he said that was a common repair. I replaced the tank and installed an anode. I'll replace it next spring.

As for the odor problem, I guess I've been lucky but in many years I have not had that problem.

[David Sinclair]

Great idea.

[thenne1713]

Originally Posted by billcf7

Modifying a pressure relief valve is illegal. I know its just a short line and fitting on the outlet

Extending the Outlet to a safe location is not an issue, that is WHY it is threaded; illegal would would be PLUGGING outlet because of drips/ leaks.

[gypsmjim]

I fill my entire water system in May and drain it in October. I only use city water. For each 10 gallons of water I add 1/2 oz. of bleach. Can't taste or smell it, no sulfur odor and no problem. The only time the HWT is on is when we are weekend camping.

What's the issue keeping the HWT full? Do we suspect corrosion? Before I fill it next Spring I guess I'll have a look inside.

[Johnynorthland]

Originally Posted by gypsmjim

I fill my entire water system in May and drain it in October. I only use city water. For each 10 gallons of water I add 1/2 oz. of bleach. Can't taste or smell it, no sulfur odor and no problem. The only time the HWT is on is when we are weekend camping.

What's the issue keeping the HWT full? Do we suspect corrosion? Before I fill it next Spring I guess I'll have a look inside.

I think it depends how often you use your rig. If it sits in the hot sun with no flow it will get stanky and contaminated. I’m in South Florida and if I let my rig sit for more than a month, I drain out the hot water tank. However, now we are Full timing in FL. I Don’t plan on draining until I park for a month during the holidays up north. Then I’ll do this mod.

[gypsmjim]

Originally Posted by Johnynorthland

I think it depends how often you use your rig. If it sits in the hot sun with no flow it will get stanky and contaminated. I’m in South Florida and if I let my rig sit for more than a month, I drain out the hot water tank. However, now we are Full timing in FL. I Don’t plan on draining until I park for a month during the holidays up north. Then I’ll do this mod.

We spend 3 days in the trailer every other week. 30 years ago I recognized the odd smell and someone suggested the lite ppm bleach thing. Been doing that for eons and haven't smelled bad water since.

Of course, in our early years we didn't have a water heater.

We have a small shed that stores 60 gallons of city water in 5 gallon plastic carboys. We transfer to the RV as needed. None of that water has ever given us an issue. We only add bleach when we transfer it to the RV.

[Bugman]

If you're draining the hot water tank, why would you even mess with the pressure relief valve? Just open up the sinks and shower faucets in the hot position and relieve the pressure that way.

[Jagiven]

Originally Posted by Bugman

If you're draining the hot water tank, why would you even mess with the pressure relief valve? Just open up the sinks and shower faucets in the hot position and relieve the pressure that way.

That only relieves the pressure, does not drain the tank. Now if you opened the plumbing's low point drain, you can accomplish the same task.

By opening the tank's low point drain and opening the pressure relief, I do not need to go into the camper. Same with filling the tank, if I am on city water.