T&P valve drain violates code & other water heater issues

[Snoonyb]

Just look at the breaker controlling the heater. It's likely 30amp, which equates to a conductor size of #10 copper.

Another method is to look on the heater itself and locate the tag which will have the heater element wattage, then divide that by 240, then, as a practical matter, add 20%.

So, a 4500 watt heater will equal 18.+ amps, + 20% will equal about 21amps.

Ergo, a 30 amp 240 volt breaker.

I am frankly amazed in your insistence in draining ANY water under your house, instead of OUTSIDE and into your yard.

Under floor areas, while ventilated, are systemically harbingers of an atmosphere that promotes mold and decay.

 

[zannej]

Just look at the breaker controlling the heater. It's likely 30amp, which equates to a conductor size of #10 copper.

Another method is to look on the heater itself and locate the tag which will have the heater element wattage, then divide that by 240, then, as a practical matter, add 20%.

So, a 4500 watt heater will equal 18.+ amps, + 20% will equal about 21amps.

Ergo, a 30 amp 240 volt breaker.

I am frankly amazed in your insistence in draining ANY water under your house, instead of OUTSIDE and into your yard.

Under floor areas, while ventilated, are systemically harbingers of an atmosphere that promotes mold and decay.

The reason is because the water heater is in the middle of the house. I'm not sure how to route the water out from under it. The condensate line for the air handler terminates just before exiting under the house and drips water under the house and has eroded the soil. I need to address that-- maybe with some quikrete or something and need to direct the water away from the house somehow.

When it rains water can go under the house as well. I should also mention that under the house is full of sand. Soil here is sandy loam and water soaks in to the soil fairly quickly.

I'm open to suggestions on better ways to route the drainage for t&p valve to get it to not drain under the house. Perhaps a floor drain that is routed out similar to the condensate line?

 

[Snoonyb]

While this discussion may seam cumbersome, by my lack of knowledge of your dwelling underfloor framing, you can clarify the generalities.

Floor joist systems seldom have changes in their orientations.

So, a floor joist cavity, the space, height and width between adjacent joists, allows for a min. of 5.5" of fall from the point of entry to the exterior of the dwellings perimeter. However, you may encounter bridging or span blocking which may need penetrating, as well as the rim joist, when routing a drain line to the exterior.

 

[PJB12]

Thank you very much, Paul!


When I eventually get a new water heater, I'm thinking of putting some scrap cement-board under the new pan- I've heard in some places you're not supposed to have a water heater sitting on wood.

I'm wondering how difficult it would be to replace the wiring for the water heater since it looks like the current one may have aluminium wiring.

I have only heard of the non-combustible floor & horizontal to combustibles requirement on many (not all) gas fired heaters. The manufacturer's installation sheet will will give specifics for your heater. I don't think electrics matter.

Replacing the wiring has to be your decision. Study access & how you will physically replace the wire. Do I have to cut, then patch holes? Can I fit where I need to fit to bring in the wires? Is there clearance to install cable staples or will the hammer not be able to swing? Questions like that.

I'd not junk it simply because is it aluminum. Aluminum is fine if sized and installed correctly.

Try this: Make the heater heat for 10 or so minutes, then feel the wiring. It should be a little warm. If it is hot, the next step is to (with power off) check your connections at beginning, end and every splice point between. Water heaters are a resistance load and resistance loads cause expansion in the conductors as they warm. The terminals can loosen over time. Aluminum alos oxidizes faster than copper if not treated with anti-oxidation paste. That can also loosen connections.



If the wiring has to go, you can also explore abandoning the wiring and starting over if there is an easier path.

If any aluminum stays and you use copper, be certain you know how to safely connect aluminum to copper. Don't ask the Home Depot guy. Sometimes they make potentially dangerous stuff up instead of saying"I don't know".

The 2" T&P to-floor clearance is so debris does not build up and stop a small drip from exiting or being visible. I've seen plenty of mice nests in the gap space.
The less than 6" is for slashing prevention (hot water) on a large dishcharge.

 

[PJB12]

I re-read above some things. It seems that you want to discharge tank flushing water under the house.
Please think of another path if at all possible.

Crawl spaces are dark and have limited air circulation. Those factors, coupled with the free food (wood, rodent droppings and fur, mite bodies and more) many species of mold and bacteria (aerobic and anerobic) will thrive.

Does your house have a weep tile system? Perhaps you can tie a trapped receptor basin into it for your hose to discharge. The receptor basin could be as simple as an upside-down reducing coupling. (I think I remember that you live in the south, so the weep tile won't be deep. Here it is 5 feet deep.)

Don't leave the hose connected to the drain when you're done. It's against both plumbing and health codes.

Problems! Problems! Problems! To many rules!

 

[PJB12]

Another method is to look on the heater itself and locate the tag which will have the heater element wattage, then divide that by 240, then, as a practical matter, add 20%.

Brief Correction: NFPA 70 calls for 125% for electric water heaters. It considers them "continuous load". (Article 220)

Keep in mind that water heaters usually have staggered elements. From the factory, never will both be on at the same time. But, people change this. Whether this has been changed or not in the heater has to be determined and the wire sized to suit.

Some utilities also wire the elements separately, requiring two branch circuit runs sized for one heating element only.

 

[Snoonyb]

Staged elec. water heater, "generally" operate on one element, until the stored water temp is expended below a predetermined level, then the second element kicks in, however there are models where both operate simultaneously.

In her apt. in NDAK, my moms was like that. The plate listed both top & bottom, but was breakered for the total.

Recovery time, has always been a short coming of elec. water heaters.

 

[PJB12]

Staged elec. water heater, "generally" operate on one element, until the stored water temp is expended below a predetermined level, then the second element kicks in, however there are models where both operate simultaneously.

In her apt. in NDAK, my moms was like that. The plate listed both top & bottom, but was breakered for the total.

Recovery time, has always been a short coming of elec. water heaters.

I've never seen one like that. It sounds quite efficient in recovery time versus the one at a time units.

I worked in a stadium that had 78 forty gallon electrics, over 200 Thirty gallon and I can't count how many 6 gallon point-of-use. They all used one element at a time. (All were off the shelf residential units) One thermostat did the switching.

On occasion for a unit with heavy use, the plumbers or health inspectors would have me or one of my guys increase the circuit and re-wire so both came on at the same time. Boy did that eat thermostats! (And lots of the load centers were FPE Stab-Lok. Not so great for those crummy bus bars either.)

 

[zannej]

My house is up on blocks and it has open air blowing through because there are only a few spots that have some sort of covering going all the way to the ground. It is usually fairly cool and dry under there. Part of the problem is that the ground underneath is uneven and there are a bunch of defunct pipes of different material types-- including metal. They get in the way when crawling under and there are some spots where there is not enough space for me to crawl. My friend can fit into spots I can't, but trying to squeeze under to run stuff is a pain.

I suppose absolute worst case I could try to find a way to run a drain to out from under the house like the condensate line. No drainage system around the house. The sandy loam just soaks the water up. But I need to install some gutters and work on drainage in some areas.

For the wiring there is enough clearance in the attic to tie on to the existing aluminium wire and pull it through to the water heater. I do need to look and see what sort of condition that wire is in inside the attic and if it is aluminium all the way back to the breaker. My friend is a certified electrician so he would know what to do.

 

[zannej]

Would getting an expansion tank be a good idea when I get a new water heater eventually?

Also, how much of a crackpot idea is this?

I could replace the tpr tube with the one I bought and run it in to an empty cheese balls container that has a floor drain embedded in it- on the platform. I'd still have the appropriate air gap. The pipe for the drain would then go out through the floor of the circulation compartment and go out from under the house and terminate over a hole/pit filled with drainage rocks.

 

[PJB12]

Would getting an expansion tank be a good idea when I get a new water heater eventually?

Also, how much of a crackpot idea is this?

I could replace the tpr tube with the one I bought and run it in to an empty cheese balls container that has a floor drain embedded in it- on the platform. I'd still have the appropriate air gap. The pipe for the drain would then go out through the floor of the circulation compartment and go out from under the house and terminate over a hole/pit filled with drainage rocks.
View attachment 33866

If you're adding a floor drain, you can skip the container and let the drain tube end above the floor drain. If the pipe that you have isn't long enough, technically you will have to extend it so that it ends between 2 and 6 inches above the floor drain's grate. (Or raise the floor drain pipe so the drain is higher)

But it's your house and thus ultimately it's your rules.
The reason for limiting the maximum distance from the end of the pipe is so that nobody gets scalded if there is a sudden discharge. The reason for the 2"minimum is two fold: One is to make water flow visible. The other is so that no pathopgens in the floor drain climb up inside the pipe and get into the tank. (Unlikely, but can happen if conditions are right.)

You could cut the bottom of the container out and set it over the floor drain. But that's a rather "cheesy" idea.

Or, when you put the riser pipe for the floor drain, you can make it long enough to satisfy the rule and instead of a floor drain, use a reducing coupling upside down. The relief valve tube will end about 2" above the large end of the coupling.

You probably don't need the hole with rocks outside because water will only go there if there is a problem or when you're testing the relief valve. Absolutely you want (need) to have the end of the pipe where you'll notice if the relief valve starts dripping or discharges suddenly.

Regarding the expansion tank:
That's a matter of both local code and your piping. I don't have one on my house's water heater. In a stadium where I worked, there were well over 400 water heaters & domestic water boilers. None had expansion tanks. But my home and these installations have so much pipe that the expansion can be absorbed into the volume of water in the pipes. In other areas of the country, expansion tanks are required no matter what.

If you have a check valve (or dual check vacuum breaker such as Watts 9D) on your main water supply, an expansion tanks is well advised.

 

[Snoonyb]

I'm more interested in the moisture monitor.

It could be mounted securely to the side of the jar, so that if & when the TPR would discharge the overheated water, because of the difference in the temp. of the discharged water, and the ambient humidity in the space, condensate would form on the exterior of the jar, and be detected.

 

[zannej]

I like the idea of the jar, as cheesy as it sounds, to prevent any splatter since it's all wood in the compartment and it doesn't look pressure treated. So I want to make sure it won't rot. I also don't want mold or mildew to build up. I have never seen an expansion tank on a water heater in this area but I haven't looked at a lot of homes.

The discharge pipe is currently long enough to go through the platform and in to the air circulation compartment.

I do like the idea of mounting the leak sensor inside the jar.

 

[Snoonyb]

I'd mount it to the outside so it's not subjected to damage from the 210 degree discharge.

Check the quality of the plastic jar, because the TPR'S release at 210 degrees.

 

[zannej]

Thanks! Good suggestions. I'll have to rig something up when the time comes. Will see if I can find info on the jar's melting temp.
My water never gets that hot though. I don't think it even gets to 120. Not sure what temp its even set at now, but it doesn't get terribly hot even at its hottest.

 

[Snoonyb]

The TPR is a safety device which will activate were there to be a control failure, in the appliance, resulting in an over-temp. condition.

 

[PJB12]

Whatever you end up doing, Zannej, I'm glad you installed a full sized discharge pipe! Your family will be a lot safer.
Paul

 

[zannej]

I haven't switched it out yet. I'm going to turn the heater off and get my friend to change it out when he's free. I don't have the hand strength and I don't trust my brother not to mess it up.

Hoping it will be soon.

 

[PJB12]

Thanks! Good suggestions. I'll have to rig something up when the time comes. Will see if I can find info on the jar's melting temp.
My water never gets that hot though. I don't think it even gets to 120. Not sure what temp its even set at now, but it doesn't get terribly hot even at its hottest.

I'd not worry about the cheese jar melting temp. I stick those things in the dishwasher all the time before re-using them for starting seeds. My dishwasher sanitizes at 160-F and the heated dry is who knows how hot.

And I really would not worry too much about discharging outside. Getting the drain outside seems like a whole lot of work.

The only time the thing will deliver water is either if there is a problem or when you test it. A water alarm plunked in a tray or in your cool cheese jar will let you know if it discharges. A wi-fi one will tell you even while you're lounging at your summer home on the French Riviera.

 

[PJB12]

I wouldn’t bother trying to fit a pan under an old heater. Moving it could cause more problems, and pans don’t hold much water anyway.

From experience, I sure agree with Tylopwort about moving the heater.

Where I worked; constantly the big shot money people would "supervise" demolition jobs and require the water heaters to be saved- From little 6 gallon to 200 gallon, 199.9-k's.

Sometimes lime scale inside was stopping a leak at the sprayed on glass lining. Moving the tank would knock the lime loose. Other times, the glass would simply crack- after all it's already expanded and contracted a bunch of times.

When one still worked upon re-installation, the plumbers would celebrate! If it worked 2 days later, more celebrating! (Rare, indeed)

And, as Tylopwort mentioned, the pans don't hold enough to help other than a quickly noticed T&P drip. (Yet are required in some installations anyway)