Navien Water Heater Flow Sensor Replacement
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- Опубликовано: 21 фев 2023
- Video short demonstrating how fast and easy it is to replace a Navien tankless water heater flow sensor. A flow sensor that is faulty will exhibit a no hot water or inconsistent hot water condition. In this particular home when lower flow water fixtures such as sinks needed hot water that there would be no hot water. High flow fixtures like a bathtub would always have water indicating that the flow sensor is starting to fail.
Tools needed are a #2 Philips screwdriver, a pail, and a pair of plumber pliers.
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Excellent. This one was so well done and explained. Seeing that it was 10 minutes long, I thought "Oh man, I need to listen to all the unnecessary ramblings of someone", but I was pleasantly surprised to see how informative and clear this video was and did not even realize when the 10 minutes went by. I am a lightly DIY person and I am now confident of taking care of this issue myself. Thank you !!
@piercedasian - My situation is where there is hot water flowing when the bathtub tap is on which has a very high flow of water. But when the shower is on, it does not heat up much. We have to start the water in a couple of sinks to get the water to heat up in the shower (and the sinks). It is not completely cold, but takes a long time and is lukewarm. Would the flow sensor be the cause of this issue? Seems like it.
Glad you like the video. I am trying very hard in my newer videos to cut down on the speaking and just get the job done but often times (b/c I teach) that omitting important details can be really detrimental especially when you're trying to teach how to fix something that can have dire outcomes if done incorrectly.
yep that would likely be the issue indeed.
Very detailed video! I am thankful for your vid, diagnosis and installation expertise. I have a Navien NPE-240-A with the exact symptom. When I run the tub hot water the burner operates perfectly and my outlet team is 125 degrees. When I run a faucet or shower I get Luke warm water. Ordered a new flow sensor on Amazon today.
Damn good job on that switch out and full explanation. That’s one of the biggest calls i would get with Navien tech support when I worked there. And explaining that backflow into the condensate if you have no oring or a bad oring.
This was great. Nicely explained and demonstrated. When I got a E438 error I was 200 miles away but near a parts source so I bought everything that could be replaced. I did the check valve first as it was cheapest. Then today there was hot water again so it was the flow sensor's turn. On reassembly I found one of the screws stripped (non-gripping) but I too forgot to put the o-ring in and had big flow out the drain. Even when I put it in, there was still minor flow. Luckily, Navien put an extra taped to the inside of the unit. Here's hoping this fixed it and I can return the recirc pump.
8k views is pretty good for a specialty video on a specific part replacement. But there's a problem if there are 8k failed 240's in the last 5 months.
^Thank you for posting. Excellent demo with clear directions. After 9 years, heat temp goes down in fixtures after a few minutes. Checked all filters (clean). Not getting any error codes. Have reset the heater on occasion and that always seemed to fix a minor issue. One video said flow rate can fool the heater by washers/restrictors in shower heads and recommended removing them. Not sure I should since it worked fine for so many years (and thinking of saving water / the environment). So now I am suspecting the flow sensor.
yep, don't remove the restrictors as they're in place to save water, your wallet, and the environment! Definitely agree the flow sensor is likely suspect. One viewer here actually had a problem with their check valve that was causing their hot water woes. I wouldn't be surprised if the flow sensor crapped out b/c that is a VERY VERY common failure point on these units. Heck if you bought a new sensor they're cheap and makes for a great spare in case they do fail when you need hot water.
Great video thank you sir!
That was an excellent video. Nice job explaining how to do it
For anyone with older model navien, just below the flow switch is a small brass knob that drains into the condendate drain. Make sure this knob is OPEN when you are emptying the service valves and CLOSED when you are refilling the unit.
Outstanding! Liked and...Subscribed to Great contents! 2 Thumbs Up! You are so easy to follow!
Replacing one of these for the first time. Thanks for the clear video.
Thanks for the note on the O-ring! I would have missed the old ring inside the old sensor if you hadn't mentioned it.
You’re very welcome. It is easy to miss especially when many utility rooms are not very well lit.
Excellent video. Thank you.
Excellent video .. very well explain thank you for a great job
Great video. Thanks for sharing
Thanks! Great video! I was able to easily do this myself and it did fix my problem!
That is awesome! Thanks for the donation. It is immensely appreciated!
thank you guy!!
my cousin and i just changed our 1st Flow Sensor 🤙🏾🤙🏾🤙🏾
you're very welcome!
@@piercedasian For some reason, I can't add a comment, so I am posting my comment in this way. This is probably the best single DIY video I have ever seen. Every detail and precaution is covered, but in such a way that it doesn't feel like being talked down to. The only problem I ran into was that one of the four screws holding the original flow sensor was extremely tight and I had a lot of difficulty removing it without stripping its head. But in the process I learned something useful: I found on Google that the smallest Phillips head screwdriver is not a number 1, but a number 0. So the size I had thought to be a number 2 is probably in fact a number 1. I had to use the next bigger size--which is apparently the number 2--and that gave me the necessary purchase to loosen the screw. I also appreciate the diagnostic and explanatory material. It is amazing how much is covered in a mere ten minutes.
Michael your comments mean a lot to me. I try to speak in layman's terms so that it's easy to understand. The goal of my channel is to help educate and for others to learn. The benefit to my viewers is they learn to be self sufficient AND they save a ton of money in the process. I've rarely had to hire work out to folks (landscaping is the only thing I can think of) b/c I see piss poor quality work all the time b/c nobody gives a damn about the quality of their work. Good job on getting the screws off. If you have the opportunity to do so, I'd go and buy new replacement screws so that you don't struggle taking them off again in the future. Screws are super cheap and there isn't a reason to not replace them if the head is a bit mangled. I admittedly struggled with the screwdrivers my relatives had in their home which is why I had to use what I had to use. If this were in my own how I would've used the proper sized Philips head screwdrivers. I just got lucky that I know what kind of forces I had to impose on the screw heads to ensure I didn't strip them from them "camming" out of their slots.
You are awesome bro!!
I have a Navien NPE-240a with the internal recirc pump. I did find and replace a bad check valve after getting an error code for the pump E348 I believe. I’m still getting the pump error code and no hot to any fixtures. When I run the hot service drain valve straight to drain I do get hot. Should I look at replacing the flame sensor before the pump? When running the test for the pump it sounds like the pump is running but still gives me the error code and 0.0 gpm on the display. Thanks
I'm not exactly sure what I"m into here. I have a Navien 240 CR that is at best giving me lukewarm water on min flow conditions. Of note, I have no error codes - which I though kind of strange. I tried a descaling procedure as the unit is 2009 but on a water softener circuit - I thought maybe over time some sediment got to the exchanger plates and probably worth doing a flush. Unfortunately, didn't work. When I got everything back after the flush and most of the hot water outlets open I had hot water. I thought - great. That must have been the issue. But on min flow conditions I was back at sqaure one. However, having seen your post on the flow adjust valve and the reasoning you were replacing it, and the fact that I have in the past few years already replaced a couple of flow adjust valves, I plan on trying that also. If it works great. If it doesn't not a big deal .. as you have pointed out. It will definetely fail in the future. Here's hopin!
Hi there The video is great. My navien tankless boiler can supply hot water to floor heating but does not supply hot water. The water is running cold in all the showers and faucets. There is no error code. The flow should be fine. What do you think is the problem?
Great video!
Glad you enjoyed it
Thanks I have almost same problem Tankless water heater looks working well but not heating water enough and no error codes in and out temperature difference is so high what causes could it be thanks for help
How do you know for sure it’s the flow sensor and not the 3-way valve (that’s on the ncb heater series) or check valve (npe / ncb). Or can you?
Where can I buy a flow sensor in Vancouver BC? If I want it today?
Any Recommendation?
Hello, Thanks so much for this video. I was able to replace the flow Sensor and it worked great for 2 or 3 days and then went back to the same old routine of just getting luke warm water. Do you think I maybe got a bad sensor or do you think it could be something else?
someone on my channel mentioned that it could be a bad check valve as well so something to consider.
Nicely done video. You're either an excellent DIYer or a trained technician! As you stated clearly in the introduction, your problem happened during a low flow condition. In my situation, it's not clear that I have the same problem but my common sense and experimental evidence seems to indicate a similar net result. Perhaps if you are willing to read on, you might give me your opinion on whether a flow/temperature sensor replacement may solve my problem. Situation: it was taking a long time for hot water to be delivered to the far side of my house, so I changed the recirculation setting to be continuous (based on some internal setpoint, but I digress) which may or may not have anything to do with it, but, now, the upstairs shower on the far side of the house gets hot water very quickly BUT it doesn't get all-the-way hot, then slowly decreases in temperature. If I then turn the shower off - which is running through 2 shower heads, so I don't think this is a low flow condition - and back on, then it gets very hot, for a couple of minutes, then the temperature goes down to a tepid temperature. I happen to have a steam shower, so I can squirt its temperature detector/faceplate with the shower water and can see the decrease from a maximum near the setpoint I have of 122, to a low of between 95 and 100 degrees. Got any ideas? I have tried to get the local Navien outfit to fix it but they want me to have a plumber present and there has been confusion and no solution between those guys so I got sick of trying and decided to try to diagnose and fix this thing myself! Cheers!
Thanks Bob! I'm not a technician but just someone that is pretty detailed oriented. I truly hate it when things aren't done right. So regarding the varying water outlet temps... I would start by replacing the flow sensor as it is one of the most common failure point on the Navien units. The part isn't overly expensive and WORST case is that you have a spare part on hand b/c it WILL eventually fail. The issue with the flow sensor is that it gives in accurate readings on the flow. While you may have a 2 head shower that it doesn't mean much as far as flow is concerned if the sensor isn't reading the flow rate correctly. The sensor in this Navien that I serviced had a near identical problem as you've described. Someone would be washing dishes and there would be no hot water and when folks shower it would get super hot and then tepid and if they turn off the tap and restart the shower then it would get hot and then act all weird and get hot and cold. I would put my money on a fault flow sensor.
@@piercedasian Thanks for your input. As it happens, I later decided that the problem was the recirc system's check valve. I replaced it, and it fixed everything. Research leading up to this decision showed that the check valves fail even more often than the sensors! The good news is that the check valve is cheap (
that is interesting. I will have to put that note into my back pocket for future troubleshooting. I may need to go out get a spare check valve too!
Very clear and concise instructions, My situation is that sometimes when I turn on the hot water tap there is NO WATER FLOWING and after a few minutes there will be hot water flowing. Could this be caused by the water flow sensor?
when you say no hot water flowing that the tap when opened literally has no water coming out of it? Is that with all taps? If so you have a blockage somewhere in your pipes or if you're on a sump/well system then the accumulator/pressure switch is not activating and turning on the well pump when it's supposed to. What type of water system (municipal or well) are you on?
@@piercedasian thanks for your reply. To answer your question, the cold water taps are ok. The problem is that when any hot water tap is turned on there is no water coming out but after a few minutes we get water flow which is hot. This happens intermittently maybe a few times a week. We're on a municipal water system.
Hey man amazing video, our Navien currently wont turn on & there is a leak. When we do manage to get it turn on for a couple sucks it automatically trigger the safety circuit breaker. Do you have any idea what can cause this? Thanks so much in advance
was any work recently done to the unit? Is the leak leaking such that its coming out of the "overflow" drain tube at the very bottom of the unit? If it is then you either have a leak in the heat exchange (expensive) or an oring has failed on the flow sensor or check valve. Best to get an exploded diagram of the parts in your unit to identify where the orings are. I even made the first mistake of NOT seeing the oring on the flow sensor and it was leaking water yet I couldn't see where from. Turns out the input on the heat exchanger where the flow sensor attaches to had a tiny oring that was stuck on the old sensor that I didn't see.
Is there a flow sensor on the hot side too or only on the cold inlet?
only on the cold inlet since it is the trigger to turn the heater burners on.
So I have a question my good man. I have just installed my first navien tankless and I just had the homeowner call me saying she doesn't have the pressure she is used to from the old 40 gallon water heater. My question is, is there a way to adjust pressure in the unit? Thank you.
Nope the water heater is a flow through system and there are no pressure adjustments. The flow rate has to fall within a specified range for the water heater to work properly which could explain why the flow is less than before. The heat exchanger is only so big and will flow “x” gallons per minute. Compare the specs of what you installed with what a typical traditional water heater to see if there is a huge deviation. I suspect there will be some but this ways you can at least intelligibly educate your customers on the observable differences.
That was my conclusion as well. I didn't think it could be adjusted. I installed an inline water filter and you wouldn't think that would drop the pressure would you? I will take your good advice and explain to the customer the nature of the system. I imagine getting conservative low GPM faucets might help as well, wouldn't you think? I appreciate your help and advice.
Hi, I do get hot water, but at first when I turn my tap on, the water hiccups and can keep a steady flow. Also if I turn the hot water on, in two different sinks or tubs at the same time, none of the two can get hot water. Is this a sign that the flow sensor is failing? Is the part you replaced the culprit? Thanks
Ps, my system has no mixing valve.
It can be the flow sensor as it is a VERY VERY common failure point. One of the viewers here had indicated that a check valve had failed. When the water is running do you hear the unit come on? If it doesn't then chances are the flow sensor has failed.
@@piercedasian I fixed it, I cleaned the flow sensor without having it to replace it and now it's working fine. Thanks though
I have a Noritz and I’m tempted to replace my flow sensor. When any faucet is on full hot no issues. Once I move the faucet handle towards the middle, the water actually gets hotter. It climbs from its setting of 120 to 140 or more. There are no error codes.
It could very well be that or it could be a wonky gas modulator valve. Typically the flow sensor will tell the control board the "flow" of water passing through the exchanger. Naturally the faster the water (and incoming temperature) is colder that the burners will burn at a higher gas rate to maintain the level of heat. Your conclusion is probably right that the sensor could be bad. They're priced reasonably so the worst is that you'd be out of a few bucks for a spare flow sensor. Best case is you've solved your problem without having to pay an expensive plumber to look at it.
@@piercedasian today I managed to get transferred to a higher tier support at Noritz. Since I have a manometer he had me adjust the min/max manifold pressures. They were definitely a little too high. The situation improved but I still think there’s an issue. The tech said my ground water being 81 degrees is the problem. He talked about Delta-T. So with the pressure adjustments my setting of 120 still climbs to about 132ish when the flow gets down to or near 1.0 gpm.
Theres actually 2 flow sensors. 1 just like have & another one with an attached white solenoid. Amazon had a good feal for both rubber washers included for $95. 3 day delivery.
do these break every year, bc i had to replace them ever year
Do you by chance have hard water or water that is high in iron? Since fixing this water heater it’s been a non issue so no I wouldn’t say it’s a yearly failure.
Thia was great. I had a plumber replace some parts and lo and behold he forgor the o-ring.
It is really an easy part to miss and even I almost missed it b/c the part is black and the utility room where the furnace is located is quite dark (as you could see in my video).
This could not be clearer. In my case there was some crud in the flow sensor impeller, so i just cleaned it and put it back in. Hot water was restored, but I may order a new part just to be safe.
Hi, I need your expert advice. Whenever hot water in the shower is turned on, the water flow/pressure goes weak then strong, then weak then strong. Also, the tankless water heater makes a pounding sound on the hot water line. Do you know what is going on and any advice on how to fix it?? Thanks in advance.
is it only the shower that does this or is this the same behavior at the taps? Are you on municipal water or well water? The flow pressure shouldn't be impacted by the water heater itself b/c its a flow through device. Have you performed any descaling maintenance on the unit at all?
@@piercedasianall I know is that we use the city’s water. It happens to both tap and showers… but mainly happens on hot water.
you'd probably want to do a descaling of the unit as it sounds like the heat exchanger is building up scale/lime buildup that is hindering its flow.
What was the reason you change it ?
I thought I was pretty clear at the start of the video. Low water flow conditions such as when using a kitchen tap or a bathroom faucet would result in no hot water b/c the flow sensor wasn't picking up water movement to heat the water.
👍👍👍👍
What was the error code number?
Isn’t this pressure sensor? Flow sensor is near dhw inlet? I’m a home owner just confused by the looks of manual
Mine is labeled WPS
Pc of cake!.......Chocolate!
It truly is easy peasy :)
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