TPR Valve... Do I need one of those?

By
Home Inspector with Superior Home Inspections - Greater Albuquerque Area InterNACHI 10041206

If you have a water heater in your house... you have a TPR valve. What is a TPR valve? TPR stands for Temperature Pressure Relief. They are installed on every type of water heater, gas or electric. They are even on tank-less systems. Why? The water in your water heater gets really hot! What happens to water when you heat it up that much? It expands! Your water heater holds a lot of energy in it's tank. I know lots of you have heard stories of water heater explosions, but have you ever seen one? Look at this video from Mythbusters, this is what can happen when one explodes.

                                                 

 

It can be devastating! Your TPR valve protects your water heater and the inhabitants of your house and should be tested yearly to insure that it is working properly. All water heater manufacturers install them in the top six inches of the tank, some are on the top and some are on the side of the unit, within six inches of the top.

So what do TPR valves do? Two things: 1) they open and release water out of the tank if the temperature exceeds 210˚F (just below the boiling point), and 2) they will open if the pressure in the tank exceeds 150 psi (the maximum normal operating pressure for a water heater.) What happens when they "pop"? The discharge of the water or pressure goes into the TPR drain line and to the floor or outdoors.

For such a small thing as a discharge line, there are a dozen or so requirements that must be met to insure your safety.  The pipe should not be directly connected to the drainage system, it should discharge through an air gap located in the same room as the water heater, should be constructed of materials tested, rated, and approved for such use, it should not be smaller than the diameter of the outlet of the valve served and should discharge full size to the air gap, it should not have valves or tee fittings installed, it should not have a threaded end, it should serve a single relief device and should not connect to piping serving any other relief device or equipment, the pipe should discharge to the floor, to an indirect waste receptor or to the outdoors. The pipe should not terminate more than 6 inches above the floor or waste receptor, it should discharge in a manner that does not cause personal injury or structural damage, it should be installed so as to flow by gravity and no loops or upward direction. Loops upwards traps water in it, it can back up to the valve and corrode the valve so it does not work, or cause it to start leaking because it will no longer seal. The pipe should discharge to a termination point that is readily observable by the building occupants.

Many homeowners try to install or replace their own water heater, it doesn't look that hard and hey.... I'll get that TPR thingy drain line outside somehow! You can see by the requirements of the drain line that it is pretty serious! Here is a few pics of some I have run across lately.

                    

Undoubtedly, these installations were not done by a licensed plumber! I know most of you are handy, but it could cause a catastrophe in your house, so if you are unsure or have no experience with water heaters (other than using one) hire a licensed plumber to install it! He will insure that it is done correctly and nothing like the video above will happen to you and your family. This is nothing to play with...

The TPR valve is your friend! When is the last time you had yours checked?

 

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Posted by

 
 
Fred Hernden 

 

 Superior Home Inspections

 

  505-588-9559

 

 **************************************************************************************

 Albuquerque, Rio Rancho New Mexico and surrounding areas...

 

“My mission is to provide superior quality home inspections to my clients to ensure peace of mind so they can confidently make the largest investment they may ever make!"

                   

Please visit my website at: www.SuperiorHomeInsp.com for details!

                 

 

                                     

 

 

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Rainmaker
569,250
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Gary - They can save your life! And definitely your house.

Dec 02, 2015 11:24 PM #37
Ambassador
605,385
Brian Schulman
Coldwell Banker Residential Brokerage, Lancaster PA - Lancaster, PA
Lancaster County PA RealEstate Expert 717-951-5552

Fred, I just had to replace a leaking TRP valve.  Turns out the expansion tank went bad, and that in turn put extra pressure on the valve and made it leak.  If the TRP valve has been leaking regularly, the expansion tank would be another thing to check.

Dec 02, 2015 11:29 PM #38
Rainmaker
1,015,377
Sam Shueh
(408) 425-1601 - San Jose, CA
mba, cdpe, reopro, pe

That photo of water heater will fail inspection in California. No drip pan at bottom, not seismically braced correctly.

In California the requirement is a lot more stringent than other states.

Dec 03, 2015 12:31 AM #39
Rainer
149,706
Michael Thacker - Re/Max Real Estate Center - Louisville
Re/Max Real Estate Center - The Thacker Group - Louisville, KY
Your best friend who just happens to be a Realtor

Great post, and something that I actually did know, ha ha! Nope, not Mr Plumber or handyman here! 

Dec 03, 2015 12:31 AM #40
Rainmaker
679,919
Nicole Doty - Gilbert Real Estate Expert
Zion Realty - Gilbert, AZ
Broker/Owner of Zion Realty ZionRealtyAZ.com

Thank goodness I've never had a water heater explode on me like that! That would do so much damage to a home!

Dec 03, 2015 01:08 AM #41
Rainmaker
680,670
John Juarez
The Medford Real Estate Team - Fremont, CA
ePRO, SRES, GRI, PMN

Am I familiar with the TPR valve on my water heater? YES!

Last Saturday, two days after Thanksgiving, my wife noticed water under our water heater. I feared the worst…having to replace the unit. Closer inspection revealed that water was seeping out of the overflow pipe. I called a professional and the TPR was replaced and it looks like we are now good to go. 

Dec 03, 2015 01:34 AM #42
Rainmaker
648,797
Bill Reddington
Re/max Southern Realty - Destin, FL
Destin Florida Real Estate

When I first started in Real Estate Inspectors always tested them. Had to have many replaced. Chances are that if you don't open a valve for 10+ years it will leak when you try to close it. Now the suggestion seems to be changing the heater because of age. Great Video. Have seen it before.

Dec 03, 2015 06:45 AM #43
Rainmaker
1,120,544
Laura Allen, Lake Tahoe - Truckee Real Estate for Sale TahoeLauraRealEstate.com
Coldwell Banker, Tahoe City, CA (530) 414-1260 - Tahoe City, CA
Tahoe Real Estate Agent Helping Buyers and Sellers

Fred Hernden - Great information for anyone who owns, or will own a home or condo some day that has a water heater and how this important value is and how it works!

Dec 03, 2015 07:28 AM #44
Rainmaker
1,317,551
Joan Whitebook
BHG The Masiello Group - Nashua, NH
Consumer Focused Real Estate Services

Thanks for the heads up.  It is best to have plumbing done by professionals..

Dec 03, 2015 12:20 PM #45
Rainmaker
569,250
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Brian - That would be a great idea!

Sam - That's correct.... earthquakes are real!

Michael - Good for you, but if you do stumble on something you're not sure of... don't be a hardhead, get help!

 

Dec 03, 2015 09:48 PM #46
Rainmaker
569,250
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Nicole - As you can see, it can destroy a home!

John - They don't last forever, thus the annual checkup!

Bill - Another reason to test it.... 10 years is too long.

Dec 03, 2015 09:50 PM #47
Rainmaker
569,250
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Laura - It's good to know!

Joan - You got that right!

Dec 03, 2015 09:52 PM #48
Rainmaker
217,052
Rob Ernst
Certified Structure Inspector - Reno, NV
Reno, NV-775-410-4286 Inspector & Energy Auditor

Your right in pointing out all the requirements need to be meet. The TPR is an important safety device. Many times there isn't a pipe installed. The worst is when there is a plug in the TPR or where the TPR should be. That's when your definetly getting into the possibility of your house looking like a Mythbusters episode.

Dec 03, 2015 10:29 PM #49
Rainmaker
569,250
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Rob - No doubt, I have never seen one missing with a plug in it's place. That would be flat out dumb...lol, I would hope a plumber would not do that!

Dec 04, 2015 11:32 PM #50
Rainmaker
1,229,952
Gene Mundt, IL/WI Mortgage Originator - FHA/VA/Conv/Jumbo/Portfolio/Refi
NMLS #216987, IL Lic. 031.0006220, WI Licensed. APMC NMLS #175656 - New Lenox, IL
708.921.6331 - 40+ yrs experience

This post is another great example of the timely and beneficial .. and yes, lifesaving ... information that can and is supplied in good measure by AR member bloggers, Fred Hernden.  Your post serves a real need and purpose .. thank you!

Gene 

Dec 07, 2015 01:26 AM #51
Rainmaker
569,250
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Gene - Thank you so much!

Dec 07, 2015 01:37 AM #52
Ambassador
1,240,851
Kristin Hamilton CA Realtor
Sun Lakes Realty - Banning, CA
(909) 557-6966- Specialize 55+ Communties Banning

Great info Fred Hernden and I will pass this info onto my community. 

Dec 11, 2015 10:46 AM #53
Rainmaker
522,119
Lisa Friedman
Great American Dream Realty - Essex, VT
30 Years of Real Estate Experience!

Fred, I am so glad that you posted this. I actually had this come up in a home inspection two months ago for the first tme in 26 years of real estate. Everyone made light about it (inspector, buyer's agent, seller). I had no experience with it and asked a few people (other inspectors, town building inspector) and they all said it was no big deal. The buyer still wanted it fixed and I wound up paying for it because it would have been a deal breaker. Now, I understand why he made such a fuss (even though the odds of explosion are probably relatively low).

Dec 11, 2015 11:12 AM #54
Rainmaker
569,250
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Kristin - Thank you!

Lisa - I would be a little worried that your Home Inspector and the town building inspector thought it was no big deal. Yes, the odds may be low, but so are plane crashes... they might think that's a big deal :-)  You don't need the protection till you need the protection... right? Have a great day!! 

Dec 12, 2015 12:22 AM #55
Rainmaker
569,250
Fred Hernden, CMI
Superior Home Inspections - Greater Albuquerque Area - Albuquerque, NM
Albuquerque area Master Inspector

Found another sweet one yesterday!

Dec 12, 2015 03:00 AM #56
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