Plumberguys -- Can you solve this mystery? (1 Viewer)

[gianmarco]

Apologize in advance for the long post.  We've had a plumber out and still no answer so far so I thought I'd reach out here for any other ideas as he'll be heading back out today.

New construction home 3 years ago.  While the service guy that has come out wasn't here for the build, it's the same company so the boss (guy who was involved) may be coming out next.

We have a Navien tankless water heater.  The heater is in the basement and the house is two stories above that.  Since we moved in, we've had some minor issues with the hot water but nothing that was a big deal to address.  The kitchen sink, on the 1st floor, will sometimes get hot water and sometimes only get warmish water.  And it's not a matter of how long we'd use it or other things running at the same time.  Again, nothing terrible, but noticeable.  Our master shower, also on the 1st floor, has hot water but would occasionally (maybe once every 3-4 weeks) only be warm-ish.  Warm enough to take a shower comfortably but just not as hot as it usually is.  Again, not that big of a deal.  One of the upstairs showers would be similar to our master in that it would sometimes not be as hot as usual.  Those have been like that for 3 years and just something we've gotten used to.

About two weeks ago we had a sudden drop in water pressure in our house.  Turns out the regulator wasn't functioning correctly.  There's been a couple water main breaks in our area and the water company came out, tested outside pressure (which was fine) and determined it was likely the regulator and we were told to call the plumber if I didn't feel comfortable trying to adjust myself.  Plumber came out, was able to adjust a bit, got pressure back just fine but said if it happened again, it may need to be replaced.  Both he and the water company said from the water main breaks that there could have been spikes in pressure and/or debris that caused it to not work.  During that same visit, he also recommended having our tankless heater maintenanced since we hadn't done so yet and it was over 3 years.  Due to hard water, he said it keeps the warranty valid and we should notice an improvement in hot water.  I agreed and scheduled to have him come out this past Monday.

During the past week, pressure was fine until this weekend when it bottomed out again for a period of time.  So, I figured when he came out to service the water heater, I'd have him change out the regulator.  Monday came and he changed that out and serviced the water heater.  All seemed good, pressure back to normal (in fact better than it had been).

That night, we went to take a shower in our master bath and there's only lukewarm water.  The same in our kitchen sink.  There's no hot water.  It's not cold, but it's barely warm.  However, the 2 sinks in the master bath have hot water.  The other shower on our first floor has hot water.  Laundry sink near the kitchen has hot water.  The upstairs all has hot water.  The bathroom in the basement has hot water.  It's only the master shower and the kitchen sink.  We've let it run for 10 minutes trying to take a shower and see if it heats up any more and it doesn't.  And this is worse than what it was previously when it would occasionally be not as hot as usual.  This is actually uncomfortable to shower in.  It hasn't gotten any better.  As for the kitchen, I've washed dishes and the kitchen sink never gets hot anymore. 

Plumber came out the next day and checked the actual faucet/showerhead/etc. and everything is fine.  It doesn't seem to make any sense and he's at a loss at this point.  He's coming back out to check temperatures but there's clearly something different since he serviced it but it's only in 2 isolated locations and they are on opposite sides of the house.  Also of note, which is strange, is that after running it for about 10 minutes, I had turned off the shower, turned it back on shortly after and had hot water for about 30 seconds and then went back to being barely warm.  That doesn't happen when I first turn it on, though. 

Any possible ideas what's going on?

 

[arrow1]

Is your basement really hot?

 

[gianmarco]

Is your basement really hot?

Nope. Stays between 68-72.

 

[arrow1]

Nope. Stays between 68-72.

#makesnote

 

[mr. furley]

https://www.reddit.com/r/Plumbing/

 

[Fat Nick]

So based on the fact that the two places you noted having issues were areas of frequent water usage (kitchen sink, master bath), my first suspicion is particulate or sediment clogging the hot water line in those two places.  

The easiest check is to turn off the hot water valve and unscrew your kitchen sink hot water supply line where it comes out of the wall - then run that into a bucket or something and see if it's hot.  What could be happening is you could have sediment that's blocking that supply line, so even though your valve is set to "hot," you're getting little/no hot water.  If it is hot, either replace, or check and thoroughly clean the flexible supply line and turn it back on.  Another check is to see if your water pressure goes lower if it's set all the way to hot.  If it does go down, then there's something blocking the hot water from getting there.  I don't think it's the heater as you wouldn't get hot water anywhere.

When we were doing work in our basement, I moved one of the main supply lines.  When I did that, I used a hacksaw to cut through the line.  All that vibration stirred up/broke lose a ton of hard water lime and sediment that then flowed through our pipes and clogged up a bunch of stuff.  I had to clean out the aerator screens on almost all my sinks, the washing machine, and remove and clean all my shower heads.  Once I got it all flushed out, it was fine again.

 

[gianmarco]

So based on the fact that the two places you noted having issues were areas of frequent water usage (kitchen sink, master bath), my first suspicion is particulate or sediment clogging the hot water line in those two places.  

The easiest check is to turn off the hot water valve and unscrew your kitchen sink hot water supply line where it comes out of the wall - then run that into a bucket or something and see if it's hot.  What could be happening is you could have sediment that's blocking that supply line, so even though your valve is set to "hot," you're getting little/no hot water.  If it is hot, either replace, or check and thoroughly clean the flexible supply line and turn it back on.  Another check is to see if your water pressure goes lower if it's set all the way to hot.  If it does go down, then there's something blocking the hot water from getting there.  I don't think it's the heater as you wouldn't get hot water anywhere.

When we were doing work in our basement, I moved one of the main supply lines.  When I did that, I used a hacksaw to cut through the line.  All that vibration stirred up/broke lose a ton of hard water lime and sediment that then flowed through our pipes and clogged up a bunch of stuff.  I had to clean out the aerator screens on almost all my sinks, the washing machine, and remove and clean all my shower heads.  Once I got it all flushed out, it was fine again.

Thanks so much. That makes sense.

Could be that it was changing the regulator that caused the issue and not the water heater flush/maintenance.

 

[wilked]

Here's my suggestion

Get pen and paper, go to basement, and try and sketch it all out.  Follow the pipes, hopefully they are labeled, and see if you can make a schematic.  It should look like this

https://www.edrawsoft.com/templates/images/residential-plumbing-system.png

Now go to your heater.  If I am correct, there should be a tee and a valve that you can connect a hose to and catch some water, right after the heater.  If there is, carefully connect, fill a bucket, grab a thermometer (buy one if you don't have one as you'll need it to diagnose this problem).  It should be 120-130 F.  If it's less than that you've got an issue with your heater

If it's 120+ F and you have warm water somewhere in the house, go catch a bucket of that water and measure it.  Do it for a bunch of your fixtures, write it all down.  

At your fixtures you typically have a hot and a cold input.  First thing I would do is turn off the local (ie under the sink) cold water shutoff.  See if that makes a difference.  If it does you have an issue with the mixing valve on the fixture.

Do some of that and report back.

Also, if you have hard water you may need to service your heater annually.  The 'hardness' (ie calcium) will deposit on the heat exchanger walls and you won't get as much heat transfer.  If you don't have hard water or if you have a softener than don't every 3-5 years should be fine

edit to add: the thing under the "A" is what I am thinking of if I have it right

https://3j06nmm5imf1ft0bmf8gu416-wpengine.netdna-ssl.com/wp-content/uploads/2017/09/Navien-tankless-water-heater-installation-842x480.jpg

If for some reason there is not a place to collect it at the heater, do everything else I said (isolate cold water, and collect hot water and measure) at all your fixtures.  Then put the data on your schematic and see if you learn anything

 

[wilked]

So based on the fact that the two places you noted having issues were areas of frequent water usage (kitchen sink, master bath), my first suspicion is particulate or sediment clogging the hot water line in those two places.  

The easiest check is to turn off the hot water valve and unscrew your kitchen sink hot water supply line where it comes out of the wall - then run that into a bucket or something and see if it's hot.  What could be happening is you could have sediment that's blocking that supply line, so even though your valve is set to "hot," you're getting little/no hot water.  If it is hot, either replace, or check and thoroughly clean the flexible supply line and turn it back on.  Another check is to see if your water pressure goes lower if it's set all the way to hot.  If it does go down, then there's something blocking the hot water from getting there.  I don't think it's the heater as you wouldn't get hot water anywhere.

When we were doing work in our basement, I moved one of the main supply lines.  When I did that, I used a hacksaw to cut through the line.  All that vibration stirred up/broke lose a ton of hard water lime and sediment that then flowed through our pipes and clogged up a bunch of stuff.  I had to clean out the aerator screens on almost all my sinks, the washing machine, and remove and clean all my shower heads.  Once I got it all flushed out, it was fine again.

If the house is 3 years old I would be amazed if it was particulate, unless there was some serious corrosion going on

 

[gianmarco]

Here's my suggestion

Get pen and paper, go to basement, and try and sketch it all out.  Follow the pipes, hopefully they are labeled, and see if you can make a schematic.  It should look like this

https://www.edrawsoft.com/templates/images/residential-plumbing-system.png

Now go to your heater.  If I am correct, there should be a tee and a valve that you can connect a hose to and catch some water, right after the heater.  If there is, carefully connect, fill a bucket, grab a thermometer (buy one if you don't have one as you'll need it to diagnose this problem).  It should be 120-130 F.  If it's less than that you've got an issue with your heater

If it's 120+ F and you have warm water somewhere in the house, go catch a bucket of that water and measure it.  Do it for a bunch of your fixtures, write it all down.  

At your fixtures you typically have a hot and a cold input.  First thing I would do is turn off the local (ie under the sink) cold water shutoff.  See if that makes a difference.  If it does you have an issue with the mixing valve on the fixture.

Do some of that and report back.

Also, if you have hard water you may need to service your heater annually.  The 'hardness' (ie calcium) will deposit on the heat exchanger walls and you won't get as much heat transfer.  If you don't have hard water or if you have a softener than don't every 3-5 years should be fine

edit to add: the thing under the "A" is what I am thinking of if I have it right

https://3j06nmm5imf1ft0bmf8gu416-wpengine.netdna-ssl.com/wp-content/uploads/2017/09/Navien-tankless-water-heater-installation-842x480.jpg

If for some reason there is not a place to collect it at the heater, do everything else I said (isolate cold water, and collect hot water and measure) at all your fixtures.  Then put the data on your schematic and see if you learn anything

I think that's what the plumber is planning on doing today with the thermometer.

Here we have some hard water but it's not terrible.  That said, when he flushed, there was a good amount of particulate in the water he flushed.  He said 2-3 years should be fine.

As for the particulate clogging the lines, both the water company as well as the plumber said that with two water main breaks on our street that had to be repaired recently (last few months), it's very possible that those repairs caused some clogging/malfunctioning of the regulator and could have gotten into the lines as well. 

The other thing I should have mentioned was that the sudden drop in pressure came during the weekend when we had a bunch of out of town family visiting.  He said with the sudden increase in water demand and it may have pushed some of that through and caused it to be more noticeable. 

The company should have the schematics for the entire house since they are the ones that did the plumbing during construction.

 

[Osaurus]

Doubtful water main break introduced debris nor a continuing reason for your issue.  Sounds like something internal.  Get a softener fwiw.  Worth every pennny.

 

[El Floppo]

A link to the likely culprit.

Or wilkeds "theory"

 

[STEADYMOBBIN 22]

I’m with the guys who think there’s particulates on the line, especially with the recent water main breaks. 

 

[Fat Nick]

If the house is 3 years old I would be amazed if it was particulate, unless there was some serious corrosion going on

Could've been from the water main breaks - especially if he doesn't have any filtration on the main.

 

[wilked]

Could've been from the water main breaks - especially if he doesn't have any filtration on the main.

True

You’d think it would be for all the neighbors then. Time to make a few calls 

 

[gianmarco]

True

You’d think it would be for all the neighbors then. Time to make a few calls 

I already did that. Neighbor across the street had a recent drop too. Others did not.

 

[gianmarco]

And something caused the 3 year old regulator to fail and have to be replaced.

 

[gianmarco]

Called Navien --

Ran the shower and then checked the unit.  Confirmed that it's 63 degrees temp water coming in, 120 degrees coming out, 1.6 gpm flow and said at that point it can't be the heater because it doesn't distinguish where it's sending the flow.

Plumber just got here and we checked temps at various fixtures.  Master sinks almost instantly up to 119-120 degrees.  Shower got to 105 and stopped climbing.  Sink in other bathroom near master also up to 120.  Kitchen sink only up to 105 (briefly to 110 and then dropped back down to between 100-105).  Other sink and laundry sink near kitchen also at 105.  Temp downstairs at 120 and temps upstairs at 120.

He said it doesn't make any sense for there to be something blocking the hot water because there's no change in pressure or flow when those are turned on.  He also doesn't think it's the mixing valves because it's affecting a few different fixtures in different areas.  He has no idea at this point and is turning it over to his boss.  He did not check the kitchen sink line before it gets to the fixture as he's going to let his boss deal with that. 

He's Shuked.

 

[El Floppo]

this is some scooby doo level mystery happening up in here...  

Spoiler

being serious- I enjoy this kind of stuff.

 

[gianmarco]

Alright, just got my thermometer and actually tested every single fixture in our house.

Bathroom in basement is 118-120 (both sink and shower).  These are close to the water heater. Another sink downstairs is ~ 110. Other side of the house.

Master sinks are 119.  Master shower is 105.  Another shower and sink on 1st floor are between 110-113.  All on the same side as the water heater.  Kitchen sink, bathroom near there, and laundry sink are 105.  Other side of the house.

Bathrooms upstairs are ~109.

110ish feels plenty warm to me so I never noticed anything upstairs.  120 feels very hot.  115ish is hot and feels good for the shower.  I would venture to guess our master shower was anywhere between 110-115 previously.  105 doesn't feel hot enough to take a shower.  That's where it currently is as well as the kitchen sink.

The strange thing is that none of these were a problem prior to his servicing the water heater and changing the regulator other than what I mentioned above.  I'll update when I find out more.

 

[Angry Beavers]

sleep with the plumber's wife - that probably won't fix the problem but your wife will divorce you and you will sell the house and not need to worry about this issue anymore. 

 

[wilked]

Alright, just got my thermometer and actually tested every single fixture in our house.

Bathroom in basement is 118-120 (both sink and shower).  These are close to the water heater. Another sink downstairs is ~ 110. Other side of the house.

Master sinks are 119.  Master shower is 105.  Another shower and sink on 1st floor are between 110-113.  All on the same side as the water heater.  Kitchen sink, bathroom near there, and laundry sink are 105.  Other side of the house.

Bathrooms upstairs are ~109.

110ish feels plenty warm to me so I never noticed anything upstairs.  120 feels very hot.  115ish is hot and feels good for the shower.  I would venture to guess our master shower was anywhere between 110-115 previously.  105 doesn't feel hot enough to take a shower.  That's where it currently is as well as the kitchen sink.

The strange thing is that none of these were a problem prior to his servicing the water heater and changing the regulator other than what I mentioned above.  I'll update when I find out more.

If you can pair this with a schematic we’ll be in good shape. 

Did you isolate the cold water valve on the lower temp ones? 

Edit it to add - shower mixing valves have their own max temp cutoff. You can solve the shower issues by increasing that 

 

[wilked]

One example of how to adjust shower

https://m.youtube.com/watch?v=lZN_pK0CCYo

 

[wilked]

The low temps at the sinks on the other side of the house...seems you are losing temp within the pipe going across the house. This shouldn’t happen unless the pipe is running along an exterior wall with poor insulation 

 

[wilked]

My suggestion - 

the heater appears to be working fine. It’s job is to deliver 120 F water. Rule out the heater 

you don’t care too much about sink temp...105 or better prob fine. So sinks seem not to be an issue. 

Open up the max shutoff on the shower valves wide open, or at least until it hits a point of “top hot”. If you can’t reaxh a temp that satisfies, bump the heater temp 5 degrees and check again

 

[STEADYMOBBIN 22]

Alright, just got my thermometer and actually tested every single fixture in our house.

Bathroom in basement is 118-120 (both sink and shower).  Another sink downstairs is ~ 110

Master sinks are 119.  Master shower is 105.  Another shower and sink on 1st floor are between 110-113.  Kitchen sink, bathroom near there, and laundry sink are 105.

Bathrooms upstairs are ~109.

110ish feels plenty warm to me so I never noticed anything upstairs.  120 feels very hot.  115ish is hot and feels good for the shower.  I would venture to guess our master shower was anywhere between 110-115 previously.  105 doesn't feel hot enough to take a shower.  That's where it currently is as well as the kitchen sink.

The strange thing is that none of these were a problem prior to his servicing the water heater and changing the regulator other than what I mentioned above.  I'll update when I find out more.

I gotta be honest, those numbers don’t sound nearly as bad as you led me to believe. 120 degrees is the default setting on a electric or gas water heater. Unless your pipes are insulated you can expect to lose a little heat just on the transfer. 

Is your master bathroom above the garage or someplace that’s colder than the rest of the house? 

 

[gianmarco]

If you can pair this with a schematic we’ll be in good shape. 

Did you isolate the cold water valve on the lower temp ones? 

Edit it to add - shower mixing valves have their own max temp cutoff. You can solve the shower issues by increasing that 

While I can see them leaving the basement, the schematic wouldn't be easy for me to put together as there's quite a bit down there.  Unfortunately they aren't labeled either.  I haven't done the troubleshooting myself yet as I'm still giving the plumbers a chance to get this taken care of.  He did already check the shower mixing valve and made sure the temp cutoff was maxed out (it already was)

The low temps at the sinks on the other side of the house...seems you are losing temp within the pipe going across the house. This shouldn’t happen unless the pipe is running along an exterior wall with poor insulation 

The pipe isn't running on an exterior wall.  And again, we've been here for 3 years without any issues really.  The noticeable temp drops just started 3 days ago and it was after the water heater service and changing the regulator.  That's what is so strange since neither of those should have caused this.  Any other ideas why it would lose temp going across the house? 

My suggestion - 

the heater appears to be working fine. It’s job is to deliver 120 F water. Rule out the heater 

you don’t care too much about sink temp...105 or better prob fine. So sinks seem not to be an issue. 

Open up the max shutoff on the shower valves wide open, or at least until it hits a point of “top hot”. If you can’t reaxh a temp that satisfies, bump the heater temp 5 degrees and check again

Yeah, the heater seems to be fine.  I agree about the sink temps although it would be nice to have our kitchen sink a bit hotter for when we wash dishes.  But, that's not a big deal and if it was just that I wouldn't really care.  I could try bumping up the heater to see if it makes a difference but I've been avoiding that both because we have a couple young kids and because it seems more like a bandaid than solving the issue of what changed 3 days ago.

 

[gianmarco]

I gotta be honest, those numbers don’t sound nearly as bad as you led me to believe. 120 degrees is the default setting on a electric or gas water heater. Unless your pipes are insulated you can expect to lose a little heat just on the transfer. 

Is your master bathroom above the garage or someplace that’s colder than the rest of the house? 

The numbers don't seem bad but our master shower right now is not comfortable at all.  The other shower on the 1st floor, which is between 110-113 is fine and feels like what our shower has been all this time. 

105 is just not good enough on a regular basis especially when it never used to be that way.

 

[Ron Swanson]

Keep in mind that hot water lines are more prone to clogging with calcium because it is LESS soluble in hot water than cold.  The opposite of most minerals.

 

[gianmarco]

Ok, very interesting update and I think may have helped solve this.

I bumped up the temp on the heater to 125. I started up upstairs and all the temps went up by 5 degrees.

I then checked the kitchen sink and it also went up by 5 along with the other 2 fixtures nearby that were in the same range.

Same with other bathroom on 1st floor near the master and the two master sinks (got up to 125).

I then checked the master shower and it felt really hot at first and I saw it bumped over 10 degrees up to 116 or 117.

That shower has a rainhead as well as a handheld where you can run either or both. I initially checked the handheld because it was an easier stream to check with the thermometer.  I then switched to the rainhead and the temp dropped way back down (by feel). I then went back to the handheld and it was also back down to 105. I checked it a few more times and it would sometimes jump up to 115 but most of the time would drop back down to 105.

My guess is that the kitchen sink on the other side has always been like that or close to it and with recent cooler temps and timing just seemed to worsen. But I'm thinking there's nothing wrong there other than it does seem to lose more heat (along with nearby bathroom and laundry room) than any other fixtures in the house.  

But, something must be going on with the mixer valve in the shower.  Everything else around it is much hotter and that's where we've noticed a definite change. 

With my complete lack of plumbing knowledge, does that sound right ( @wilked )? If so, just need to get that fixed? And that shouldn't go out in 3 years, right?  

 

[Osaurus]

Fetzer valve needs to be replaced for sure.

 

[DaVinci]

Another factor to rule out: is your house built on an Indian burial ground?

 

[Osaurus]

Another factor to rule out: is your house built on an Indian burial ground?

 

[wilked]

Ok, very interesting update and I think may have helped solve this.

I bumped up the temp on the heater to 125. I started up upstairs and all the temps went up by 5 degrees.

I then checked the kitchen sink and it also went up by 5 along with the other 2 fixtures nearby that were in the same range.

Same with other bathroom on 1st floor near the master and the two master sinks (got up to 125).

I then checked the master shower and it felt really hot at first and I saw it bumped over 10 degrees up to 116 or 117.

That shower has a rainhead as well as a handheld where you can run either or both. I initially checked the handheld because it was an easier stream to check with the thermometer.  I then switched to the rainhead and the temp dropped way back down (by feel). I then went back to the handheld and it was also back down to 105. I checked it a few more times and it would sometimes jump up to 115 but most of the time would drop back down to 105.

My guess is that the kitchen sink on the other side has always been like that or close to it and with recent cooler temps and timing just seemed to worsen. But I'm thinking there's nothing wrong there other than it does seem to lose more heat (along with nearby bathroom and laundry room) than any other fixtures in the house.  

But, something must be going on with the mixer valve in the shower.  Everything else around it is much hotter and that's where we've noticed a definite change. 

With my complete lack of plumbing knowledge, does that sound right ( @wilked )? If so, just need to get that fixed? And that shouldn't go out in 3 years, right?  

Ya you got it

One more way to confirm...  Can you isolate the cold water to that shower?  Showers typically don't have local shutoffs, so it might be tricky.  You might be able to isolate your cold water to multiple services in the basement (make sure you don't isolate the feed to the hot water heater), and then repeat the test.  If the temp goes up to match the other fixtures than definitely the mixing valve.  

Hopefully they built an access panel for the plumbing to the shower valves...otherwise might be a little demo work to repair / replace

 

[SWC]

my suggestion is just take a shower in your kitchen sink since it is so effen hot no need to pay any more plumbers and you save money that you can take to the bank brohan