How to Test Your Water Heater's Temperature & Pressure Valves | Roto-Rooter 

It didn't blow up from a faulty T&P valve it blew up because the heating controls failed and someone plugged up the T&P outlet. Your information is misleading. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ug6gi2053wE.html

Never ever had any maint. on any past hot water heaters and lasted 30+ yrs.!!!!!!!!

You are very welcome. Dave is definitely an expert. We add new videos every week to help you with various plumbing concerns. We hope you will subscribe to Roto-Rooter on RU-vid and follow us on Facebook, Instagram and Twitter too.

Thanks, Loretta. We're glad you watched and we're happy the video was helpful to you.

So nice of you to say so. Thanks for visiting our channel

You're welcome!

Do you have hot water coming out of your faucets? It's full! Do you have air coming out of your faucets instead of hot water? It's not full.

@@f.demascio1857 thanks - that's good info I didn't know...

Yes, it depends on state and local plumbing codes. Expansion tanks aren't required everywhere. We're glad you got your valve replaced. There's peace of mind knowing it'll work if heat and pressure build up in the tank.

Debris trapped between valve seat and disc. take apart clean, lap as require, and make sure you record compression screw depth to retain approximate set pressure.

Thank you for your opinion. We don't know which comment you're talking about, but we didn't remove it unless you used inappropriate language. As you can see from the comments section, several others brought up the same point you made and their comments weren't removed. And you can clearly see our responses if you scroll down. Many of our plumbers share your opinion, but our most experienced Master Plumbers disagree. They say, "better safe than sorry." You say "they (T&P valves) always work." But that's just patently false. T&P valves, though very reliable, are known to fail at a rate approaching 2% on valves just 4-5 years old. The failure rate escalates considerably as valves age. The National Board of Boiler and Pressure Vessel Inspectors recommends regular T&P valve testing. They also recommend removing and visually inspecting T&P valves for accumulation of corrosion deposits every three years. But at just $15 for a new valve, it's smarter to just replace them when they begin to leak after a test. Better to test it and KNOW it works than to assume it's OK and suffer an explosion. The T&P valve is the only thing preventing a water heater from exploding if heat and/or pressure get too high.

Misleading statistic at BEST. The failure rate you speak of is NOT in failing to protect the water heater from blowing up, but failing in regards to leaking and such. Think about it? If the failure rate was that high, you would have hundreds of homes per week exploding!!! And you've made mention of this $15 part many times. But that's not the end cost for the homeowner. 35 year retired Master repair plumber.

The odds of the water heater exploding are so minuscule it's not even something to be factored. Another words, bang for buck, considering the leaks that can be caused by checking it, it's NOT a good exchange to prevent something that simply never happens to begin with :)

Again, thanks for your opinion, but we think we'll stick with what our Master Plumbers have advised is the safer route and follow established best safety practices on behalf of our customers.

Thing is James sometimes it is just sediment there that causes it to leak steadily - opening it and flushing the line/valve out can help to clear it and produce a better seal - happened with mine.

That sounds like a job for one of our plumbers. You can schedule a service call at 1-800-GET-ROTO. If you would like to ask your question to one of our master plumbers, please visit our free "ask the plumber" page on our website. Here's a link: www.rotorooter.com/plumbing-basics/ask-the-plumber/

You replace the valve. We don't like the options either, but the whole point of having the T&P valve is to prevent a tank explosion. The only way to know if the T&P valve is working (and protecting you and your family) is to test it. Sometimes they get fouled with minerals and leak, meaning they are failing and need to be replaced.

That sounds like a problem other than pressure and heat, so I don't think so. My guess would be burner/heating element and the need to tighten fittings. But it sounds like something a plumber ought to check out.

Just the expansion tank.

Given the dangers of a natural gas flash fire or explosion, I recommend that you call a licensed plumber right away to check out your system in person. There are simply too many possibilities that can't be accounted for without seeing it first hand. Call 1-800-GET-ROTO to reach your local Roto-Rooter Plumbing & Drain Service office. I won't risk giving you incorrect advice. Of course, you can also submit a question using our Ask a Plumber features, in which a licensed Roto-Rooter Master Plumber will respond to your question. However, due to the number of questions he receives, it may take up to 48 hours to get an answer. www.rotorooter.com/plumbing-basics/ask-the-plumber/

+Danny Diet Your question would best be asked on our website's free "Ask the Plumber" feature so you can get an answer from a licensed, experienced Roto-Rooter plumber. www.rotorooter.com/plumbing-basics/ask-the-plumber/

RotoRooterTV Job all done not leaking your video had gd ideas but ultimately had to replace relief valve it was covered with corrosion. works great.

+RotoRooterTV o

HI Stacey. I'd like to refer you to our free Ask the Plumber feature at RotoRooter.com where you can submit your question to a Master Plumber and get a helpful, detailed answer. Here's a link: www.rotorooter.com/plumbing-basics/ask-the-plumber/

Is it discharging that much water through the temperature and pressure relief valve? If so, you should have it examined by a plumber right away. Call back whoever installed the water heater. Since it was only three months ago, the work is probably still under warranty.

Yes, do not set it so high. Best setting is 120°

If you mean the pipe at the top of the water heater that carries hot water from the water heater to the plumbing fixtures in the house, then yes. It will be hot to the touch. The other pipe on top delivers cold water into the unit to be heated.

I need to make sure I understand what it is you're asking. When you say "fume" do you mean "fumes?" As in smelly gas fumes? Or did you mean "foam?" Nothing should be coming out of that drain faucet at the bottom of the water heater except water when the valve is open and any sediment that may be piling up at the bottom of the tank. The relief valve tube could be hot because the water inside the tank is hot and the tank and everything connected to it will also become hot. If you have serious concerns, please call a plumber for an inspection and tune-up. However, check the age of your water heater. These appliances usually last 11-12 years. If yours is close to that in age, evaluate whether serious repairs make sense on a unit that you may be replacing in the next year or two anyway.

It should match your incoming water pressure.

It may be a black pipe or even a PVC pipe. Most often it's copper, but if it's coming out of the T&P valve and running vertically down the side, that's all that matters.

@@RotoRooterTV mine doesn't have a pipe connected to it at all. Should it always have one or is it fine for it to not have one and it can be attached when testing the valve? Otherwise it's so high up that any hot water splashing out would splash on your face with how close you have to stand to it to reach the valve release.

@@XSemperIdem5 Plumbing codes require a vertical pipe extending down to the floor or almost to the floor. Yes, yours should definitely have the pipe installed to prevent hot splashes.

Thanks for commenting. I don't know the answer to your question, but I invite you to ask one of our master plumbers. It's a free online Roto-Rooter service called "Ask the Plumber." Here's a link: www.rotorooter.com/plumbing-basics/ask-the-plumber/

Yea it's connecting to another drain somewhere

Lol!

That's very unusual since the heater should no longer be functioning and building pressure if it's turned off. You should be able to open the T&P valve manually to relieve pressure in the tank, but if pressure continues to build, you should replace the T&P valve or call a plumber to do so.

@@RotoRooterTV thank you for the response...I discovered that there is a pressure regulator in the crawl space...I wonder if it is malfunctioning...I know that pressure before it is pretty high but there is not a gauge...thanks again for your time and halp.

Yes, unfortunately, the T&P valves are notorious for leaking if you haven't tested them regularly from the outset and then, after a few years, do so for the first time. The usual culprit is a grain or two of calcium that gets caught between the valve's rubber seal and metal body, allowing water to get past the seal. Sometimes you can open and close the valve a few times then lightly tap on the valve pin with a screwdriver handle. This action sometimes reseals the valve seat and stops the leak. But other times the valve simply fails and will need to be replaced if it is more than an irritating drip. This is an annoyance, but it helps to remember that that little valve is the only thing preventing your water heater from becoming a bomb that could damage your home and everyone inside.

Could be several things, but if it's getting power but not heating water, a good guess is there's a bad heating element. But most electric water heaters have more than one heating element and the chances that more than one went bad are slim. More likely there's a power delivery issue. Is the water getting warm at all? We suggest you call a plumber for an accurate diagnosis. But if you have time on your hands, try using our "Ask the Plumber feature" on our website: www.rotorooter.com/plumbing-basics/ask-the-plumber/

Could be. You might want to check the age of your water heater. They typically last 11 years. The serial number typically incorportes the date of manufacture. If you haven't had a water heater tuneup in a few years, it may be time to call a plumber.

@@RotoRooterTV Many thanks. Had plumber in - water pressure reduction valve u/s - very little water getting through, build up of steam causing boiler to run very hot and RV letting go - expansion tank also full. That was drained and both valves replaced - 1 hr 20 mins later all good - and for $225 CAD am well pleased. Thanks for posting these vids and your reply - have a great 2019 ! Cheers from NS.

Hi Rich. I don't understand your question besides the part about your pressure valve being loose. It should not be loose and can be tigtened with a wrench very easily.

I couldn't say without seeing it.

@@RotoRooterTV i looked into it. its a secondary relief valve should the main one cease up. i just replaced my unit. Thank you

Expansion tank not only helps to regulate pressure of the water heater, by helping regulate it also helps extends the life of the heater. Granted the expansion tank is mounter properly; vertically hung not horizontal.

@@Killinza89 I have never see that Expansion tank here on the desert. even installed a new one and no Expansion tank at all by Tech.

No. Code demands that it go to the ground.

That's very strange. I suggest you submit a question to Roto-Rooter's Ask the Plumber feature. Go here: www.rotorooter.com/plumbing-basics/ask-the-plumber/

Either your gas valve is bad or your high limit switch is bad.

Yes, Dave was raised in Philadelphia.

Roto-Rooter me too! South street baby!

Assuming it's a gas water heater, is your burner lighting but not staying lit? Or is it not lighting at all?

Sounds probable.

This may be too easy or obvious, but if the water heater is actually inside your apartment, have you tried turning the temperature dial up? Depending on the building's configuration, sometimes apartments share a water heater or boiler and it may not be accessible to you. We empathize with your problem. Taking lukewarm showers is less than satisfying.

@@RotoRooterTV where would the dial be located (which lever)?

@@LyndaE79 If you don't see a dial in plain sight on the side of your water heater, then you probably have an electric water heater instead of a gas heater. It's a little trickier to adjust the temperature on an electric heater because you have to open two panels on the side of the tank (after turning off electric power to the unit) because full size electric water heaters have two heating elements, one near the top and another near the bottom. If you have a tiny, apartment-sized water heater, your unit may only have one heating element. We don't currently have a video showing how to adjust the temperature on an electric water heater, but here's one that shows the process very well. Please follow all safety warnings: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-yh8omS9oLTE.html

Not a 911 emergency. No life or property is at stake. It is a civil matter. Consult a lawyer and threaten to sue for not meeting the residence agreement.

There are different types of boilers and boilers work differently than water heaters. It depends on the type of boiler you have and the type of pressure relief valve is on the boiler. However, every boiler should have some type of pressure relief valve that is designed to relieve excessive pressure on its own. I'm not sure why your boiler installer told you to manually relieve pressure from your boiler, but there are enough variables with boilers that you should get a second opinion from the next guy who maintains and inspects your boiler. It probably requires an in-person assessment to see your equipment up close.

@@RotoRooterTV yeah, i think you are correct. I have asked several people and they all told me what you just told me. Don't need to mess with it. I guess I won't do it no more. Thanks for your help!

@@RotoRooterTV One more thing. Whenever people release the pressure relief valve manually is that hot water coming out from the pipe?

@@MusicLuv80 "Yes, it is hot water. Go back and watch the video from the 2:02 mark where the plumber says, "stand back and don't do this if you're barefoot or wearing open-toed shoes or sandals. If that hot water splashes out, you could be burned."

@@RotoRooterTV Yes, you are right. Lol ~ Thanks for your answers.

We're not quite sure what your mean. But if yours is a gas water heater, here's a video showing how to relight your gas water heater and turn it on. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Xp_dMW8fSKg.html

@@RotoRooterTV so I think my landlord is refusing to give me heat, even I pay for it my self, I have to turn my termostat all the way to 80 to turn on, and if I put it even 79 it shuts off. And the heat don't even feel like it's pushing 80, more like 50.

@@vfwvfw123 Are you talking about the thermostat on your water heater or for your furnace? The water heater should be set to 120-degrees Fahrenheit for optimal hot water efficiency and safety.

Yes the water heater, but I guess my landlord De pressure the water less I gues to save money, even thou I pay with my own money to national grid

@@vfwvfw123 Do you mean the water pressure in the house is low when it comes out of your faucets? If there is a pressure regulator where the main water supply line comes into the house, it's possible to adjust the pressure up or down. Without such a device, that would not be possible and your pressure problems could be occurring before the water ever comes into the house - at the municipal level. A plumber can check that out for you.

That's terrible and extremely dangerous.

There are many possible reasons, depending on the age of your home, what the pipes are made of, etc. There could even be a partially closed gate valve in the water supply line connecting the kitchen. We're confident that an experienced plumber could identify the problem if you've exhausted all the possibilities on your own.

Yes, it is normally pretty hot to the touch, but check your water heater's temperature. It may be turned up too high, but not high enough to engage the T&P valve. Set your water heater's temperature to 120-degrees Fahrenheit. This is hot enough to give your household a reliably supply of hot water but not hot enough to cause scalding.

@@RotoRooterTV My pressure relief valve is not hot nor warm. What does that mean?

+roxydog 2004 Expansion tanks on water heaters are part of the plumbing code now in many parts of the country.

+RotoRooterTV On a water heater ? ,I have one on my boiler ,but why on a water heater , that's what the relief valve would be for ,unless you have the tank set higher than 120 DF,I know codes change all the time ,good to know ,thanks

We hear exactly what you're saying. This topic is a matter of debate among our plumbers too, especially those from different parts of the country who aren't necessarily subjected to the same plumbing codes. But the plumbing code writers cite a number of reasons for putting expansion tanks on water heaters, and of course we follow all local plumbing codes in order to keep our customers' plumbing in compliance. Here's a link to one of the better explanations: plumbertalk.wordpress.com/2014/01/07/expansion-tank-that-thing-on-top-of-your-water-heater/

Yes, whoever installed the water supply lines did NOT install an expansion tank. NOW IT IS ON ME to install one! I don't know how they managed without it.

If your pressure relief valve is working why would you need an expansion tank? If your pressure relief value is not working and your tank overheats, what's to stop it from exceeding what the expansion tank contains and still blowing up?

We understand your frustration because some local plumbing codes require the discharge tube to extend to within an inch or two of the floor or the overflow pan. Other codes allow the bottom of the tube to be high enough above the floor to easily allow placement of a bucket beneath it. You may have to get creative and wedge a sturdy cup or a paint roller pan beneath the discharge tube. Whatever you do, try to minimize the risk of getting splashed with hot water by standing clear as best you can. This is never a perfectly safe situation.

That sounds like a gas water heater. They do exhaust outside the house. Power vents tend to vent to the side of the house.

That's not ideal because the fact that water is discharging out of that pipe means that your tank is either too hot or it is building up too much pressure. If it hasn't been inspected or tuned up by a plumber in a few years, you may want to have it looked at. Keep in mind that the average water heater lasts 11-12 years. If yours is older than that, you're on borrowed time and you may want to begin budgeting for a new one, rather than make extensive repairs to an appliance that may not last much longer anyway.

He capped the pipe where the T&P valve should be? That's a very dangerous situation. We suggest you send your landlord a link to this video and insist he have a plumber install a working temperature and pressure relief valve right away.

RotoRooterTV Thanks for the info

RotoRooterTV it's been like that for ten years with no maintenance and it makes popping noise oh and there's literally no pressure relief valve it's a cap on the gas water heater it's self

That could easily turn into a dangerous situation. Check out this news report of an exploding water heater due to overpressure. This wouldn't have happened if the water heater had a functioning temperature and pressure relief valve. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-TpjYgQURQ7o.html

RotoRooterTV holy S*** am gonna do this my self screw my landlord he is a lazy old man that lives like 2 hours away from me is there a video that shows how to turn it off

That's difficult to say without looking at your entire plumbing system. Is cold water coming out of the hot water taps in the bathroom sink and shower, or no water at all?

You should have that checked out ASAP.

Yes, we've heard it has a very different meaning down under.

I agree with you on the expansion tank, relieving the air makes no sense as any kind of "test". I don't understand why you say the relief valve never needs to be checked. PRVs have been known to fail from obstruction due to minerals. They do need to be checked every so often.

gurgy3 Simply because I have changed out hundreds of water heaters in my history of over 40 years of plumbing and I always drain the tank of course before removal to make it lighter. Each time I hook up a hose and then pop the relief to allow air into the tank to facilitate better drainage. Each time air passes through without a problem. These are on tanks from homeowners who never "tested" their relief valves because I have never even heard of this scheduled practice before recent days. Tanks that usually last 10 to 15 years and sometimes up to 20 years. Basically sediment collects because flow carries sediment to places. There is no flow through relief valves so there is very little accumulation aside from the temperature sensor rod with the fuseable link which has water passing over it inside the tank. Even then there isn't usually very much accumulation on it and occurs more on tanks with the side mount valves. If you have well water very high in mineral content, I possibly could recommend changing it out maybe every 5 years or so, but I would rather say remove it and visually check for sediment accumulation by looking into the inlet. I would not recommend reliving water pressure through it, because odds are it will then develop a leak and need replacing from dislodged mineral sediment getting between the valve seat and the washer. You are however welcome to do as they say here and learn for yourself. I'm just saying it isn't necessary. If it was, a long time ago, instructions on the box would tell you to periodically check the valve. It doesn't, because water heaters have used them since they were invented and were built to be fail safe. I have never known one to fail from obstruction, just stupid people who, when they started leaking, fixed them by plugging them off rather then replacing them. Is your knowledge of them failing from first hand experience or from here say? I became a Journeyman in 1972 and most of my life as a plumber I was in service work with short bouts in construction.

gurgy3 Mine was clogged with hard water minerals...I just don't know why it opened up. Fire Dept across the street is always opening up the hydrants..testing equipment..and not flushing the line before closing it..Air pockets build up in the main feed..I turn on the faucet and it SPITS air, as if I turned my water line. They have to be the culprit.

+OCZ0 Because the expansion tank is installed upside down, pressing the schrader valve and expecting water to come out on a bladder failure is incorrect. The air will stay trapped at the top of the tank and it will continue to function as an expansion tank.

+toysareforboys At first it sounded like you were disagreeing with me, but a careful read showed in theory you are agreeing with me. You are correct in assuming the air will remain trapped at the top of the tank. Again, that is only if people don't let that air out as suggested in the video without replacing it. Expansion tanks are dual purpose and it's not really clarified as to how they work. The bladder also serves as a shock arrestor. Quick closing valves on today's faucets can cause "Water Hammer" The banging of the pipes that occurs when a system does not have sufficient "air chambers" installed at each fixture. That instant stopping of the water can produce Hydraulic type pressures in a system not designed for those kind of pressures. The rubber bladder inside an expansion tank with the "air buffer" between the bladder and the outside walls of the tank itself provide an extra level of expansion and can absorb that "shock" to the water tank on a water heater. The bladder itself is simply a protection for the tank itself so it doesn't rust out from water exposure. It also prevents the mixing of the air and water to help alleviate the loss of the captured air into the system through turbulence. Not that there is much turbulence at the top of a expansion tank, however over time that air would be lost to the system. As far as other comments on this video. The city of Chicago and water heater manufacturers all recommend 140° as a set temperature. This also corresponds with dishwasher specs. Setting it at 125° doesn't save anything, in fact it causes your water heater to cycle sooner whenever hot water is used. Commercial water heaters should be set at 160° as per dish washing machine specs.

Depending on the age of your house and the city codes you may not need one. Usually a tank is required if you have a back flow prevention check valve on the water supply line after the water meter.

We beg to differ. A number of master plumbers have weighed in on this topic, and yes, opening the valve is a sure-fire way to cause the valve to leak if it is several years old and has never been tested before. But it is far more important to know that the temperature and pressure relief valve will work as it was designed to, if and when the pressure and/or temperature exceed what the tank can handle. That inexpensive ($15) little valve is the only thing preventing a water heater tank from becoming a bomb, so better to test it every couple of years and know that it is reliable and will protect your home and family than to worry about a drip.

​@@RotoRooterTV You are totally wrong and very misleading. It is a temperature and pressure relief valve. How is manual actuation testing the temperature or pressure function? The answer is it doesn't. Manual actuation is a senseless destructive test. Simply referencing a bunch of master plumbers that are completely wrong does not in any way change the facts but, instead shows that you and they are wrong. The manual actuation only verifies that water flows through. If manually actuating the valve causes a leak that means it is misaligned and possibly jammed at this point. You have now potentially made the valve non-functional. Negligence. This is so obvious but since you don't understand it perhaps you could consult with the National Board of Boiler and Pressure vessel Inspectors (NBBI). These valves should be removed and inspected for scale. Particularly if the home has any noticeable scale on any of its fixtures. If there is no scale buildup around the port then the valve is fine, do not manually actuate it. If you want to actually test the valve then remove it and expose it to the specified pressure and see if it actuates. Then expose it to its specified temperature and see if it actuates. But now you have senselessly monkeyed with the valve initiating the potential for corrosion and or a leak. After compromising the integrity of the valve and charging a homeowner for this, the T&P valve will very likely soon leak. The angry homeowner then unknowingly and foolishly plugs it up. This is why the water heater in the video blew up. The outlet was plugged by the homeowner because it leaked. The explosion was not due to a T&P valve failure as you misleadingly imply. (This was covered on This Old House) The water heater blew up because the temperature controls failed and allowed the water heater to overheat. On top of that, the safety system was disabled. The whole water system of the house was isolated by either a check valve or backflow preventer or pressure regulator preventing the water pressure from pushing out back into the incoming water main. So the pressure in the house built up due to heat expansion. The water heater, being the weakest component of the system, ruptured releasing high-pressure hot water allowing that water to expand and "flash" into steam, an expanding gas, and propellent. As far as the expansion tank no one should ever be messing with the Schrader valve. Most expansion tanks are precharged to 40psi. Ideally, they are set to match the incoming water pressure. It is extremely rare that these tanks are ever installed correctly with an isolation valve that has a bleeder on it. Such an installation would allow both a pressure test and pressure charge of the expansion tank. Short of that, a homeowner would need to drain the whole water system to relieve the waterside pressure and then place a pressure gauge on the Shrader valve, hope for 40psi. Telling someone to release air out of their expansion tank is just plain negligence.

In certain parts of the country, the plumbing code requires an expansion tank. But not everywhere.

Yep, Dave's from Philadephia, originally.

@@RotoRooterTV go birds.

@@mikenordeman4642 no

Tested the pressure relief valve and now it leaks. I should have just left it alone.

Unfortunately, opening the valve is the only way to know for sure that it works and will prevent a tank explosion if the temperature or pressure gets too high. We know it's a debate that plumbers everywhere have, but we feel strongly that it's better to be safe than sorry when it comes to T&P valves.

@@RotoRooterTV can turning off the main water source also help

@@RotoRooterTV can these pressure relief valves be turned off?

No, but a temperature and pressure relief valve can be removed or bypassed. But, no licensed plumber would ever do such a thing because it would put the occupants of the dwelling in grave danger. Here's what can happen when pressure inside a water heater builds up to extremes and there is no pressure relief valve or the relief valve has stopped working: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-TpjYgQURQ7o.html

Because those 80%ers never check their valve.

Well water supply, maybe..but city supplied water usually does a pretty good job about killing most germs. I've had my electric water heater set at factory 125 degrees for one year and noticed drips coming from the PRV ..after inspecting, some hard water sediment had settled in around the seat. It opened up for some reason. We do have high water pressure, but not sure how high..greatly doubt it's enough to exceed 150 psi. Setting Thermostat to 140 degrees? Go for it.

In Chicago we usually set water heaters at or around 140°

It states on most water heaters that manuf. recommended temp is 120 to 125 depending on the unit. Before bashing the person who posted the video you might wanna do your homework.

Control of Legionella growth can occur through chemical or thermal methods. The more expensive[citation needed] of these two options is temperature control-i.e., keeping all cold water below 25 °C (78 °F) and all hot water above 51 °C (124 °F). The high cost incurred with this method arises from the extensive retrofitting required for existing complex distribution systems in large facilities and the energy cost of chilling or heating the water and maintaining the required temperatures at all times and at all distal points within the system.ChlorineA very effective chemical treatment is chlorine. For systems with marginal issues, chlorine provides effective results at 0.5 ppm residual in the hot water system. For systems with significant Legionella problems, temporary shock chlorination-where levels are raised to higher than 2 ppm for a period of 24 hours or more and then returned to 0.5 ppm may be effective. Hyperchlorination can also be used where the water system is taken out of service and the chlorine residual is raised to 50 ppm or higher at all distal points for 24 hours or more. The system is then flushed and returned to 0.5 ppm chlorine prior to being placed back into service. These high levels of chlorine penetrate biofilm, killing both the Legionella bacteria and the host organisms. Annual hyperchlorination can be an effective part of a comprehensive Legionella preventive action plan.

more often than not, a light tap on the pin with a screwdriver handle will take care of it.