Lack of Hot Water in Shower

[ExFlyBoy5]

I have scoured the internet and haven't found much information on our issue and thought that someone here might be familiar with/can assist.

We had a shower that had a thermostatic valve that was leaking into the wall. It just so happened that the water heater was also leaking, so a plumber replaced the shower valve and water heater. Now, the shower is markedly cooler than it was with the old valve. I know there is a anti-scald limiter on the valve, so with the help of Youtube, I was able to adjust the limiter to allow more "hot" water, but it's still not enough. We have adjusted the water heater to 75% of the maximum temp but do not want to go much higher to avoid running the heating elements for hours on end (and resulting in premature failure).

Currently, the full hot water out of the bathroom sink is 120 degrees while the shower will not get hotter than 96. I understand the purpose of the anti-scald valve, but 96 seems ridiculous to me. It appears that if I remove the adjustable limiter, you will not be able to adjust it at all. Probably designed that way to minimize lawsuits.

So, any suggestions as to what I might do to fix this?

 

[Sunset]

A tank water heater won't run for hours on end if set to high, as once it heats up the heat stays in the tank for a long time, and just needs the occasional more heating to keep the temp super hot.

But the bathroom sink is getting hotter water, so the problem is not the tank setting.

Why do you have an anti-scald valve (this seems to be the issue to me).

 

[Big_Hitter]

Why do you have an anti-scald valve (this seems to be the issue to me).

prevents surprises when someone flushes the toilet

 

[calmloki]

Been a few years, but isn't there a knurled wheel that you can lift off and reset at the valve? not just turn the wheel within it's limits?

 

[CardsFan]

It appears the anti-scald valve is limiting your hot water flow to about 66% of total flow, based on a quick calculation.

If there is no more adjustment in the limiter, your only choices are to either raise the hot water temp, or add a valve or orifice to the cold water line to restrict the cold water flow (of course this defeats the whole purpose of the anti-scald valve).

FWIW, 120F sounds low to me for a hot water heater setting.

 

[Gumby]

Or you could go old school and have two separate valves -- one hot, one cold -- and do your own mixing. That's what we have, and the temperature is always exactly the way I want it. We have the same set up on the sinks. I really dislike showers/spigots with a single, mixing valve. And I haven't scalded myself yet.

 

[target2019]

I was at kid's rental this past weekend. HW tank was set to max temp, and it ran a lot...even though it was middle of night and no one using.

So I set the temp down a notch or so, and it was obvious over next day that the gas did not cycle on as much. Their water is still too hot, in my opinion. We keep ours at Low, which means there will never be a scalding injury.

 

[RobbieB]

Yeah with water max at 120F, scalds are not a problem except with children. Nix the valve.

 

[zinger1457]

I would have the plumber come back and check it out, maybe he installed a faulty valve, typically those valves are preset to ~105 but have a 120 degree upper limit.

 

[samclem]

It just so happened that the water heater was also leaking, so a plumber replaced the shower valve and water heater. Now, the shower is markedly cooler than it was with the old valve.
. . .
So, any suggestions as to what I might do to fix this?

Call the plumber back who installed it? Assuming he/she chose the valve and set up the water heater, he/she shouldn't have left your house until you could take a comfortable shower. If the anti-scald feature of the valve can't be sufficiently adjusted to allow you to have a comfortable shower, then it's probable that a new valve body will need to be installed--and that's a lot of work. I'd sure let the plumber who created this problem fix it.

120 deg F is the very lowest recommended setting for a water heater (the DoE likes it). Even a little cooler makes it possible to get some nasty bacterial growth in the tank. I keep ours warmer than that, and scald risk is still very low.

The best way to avoid scalding and inconvenience from flushing toilets, etc, is to have sufficient cold water pipe capacity so that pressures at the shower valve don't change much when someone flushes a toilet. In some cases it's easiest to just run a new 5/8" PEX cold water line from the shower valve back to where there's a large water pipe. That's a lot less trouble-prone than any thermostatic valve.

 

[JoeWras]

I volunteer doing maintenance at a retreat center and all I can say is that those anti-scald valves constantly give us issues as you describe. Due to lawsuits, we can't turn up the hot higher than 120 or so, so we have to tell the cold shower complainers to just buck up and take it. AKA, that exactly describes your problem.

I won't tell you to buck up and take it unless you want me to.

 

[ncbill]

Old school is the way to go, separate hot & cold...I mix mine myself, no need to futz with anti-scald devices.

 

[ERD50]

Agree that 120F is low, and that setting it somewhat higher is NOT going to make it run far longer. The difference between raising water from 60F to 120F, versus 60F to 135F isn't that great. A 75F delta, versus a 60F delta means it might run ~ 15% longer cycle, plus a teensy-weensy (yes, that's an SI unit!) bit more to account for a bit higher standing loss. But not a lot at all.

Originally Posted by Sunset View Post
Why do you have an anti-scald valve (this seems to be the issue to me).

prevents surprises when someone flushes the toilet

There are at least two different types of controls here, and I think they are getting confused.

The type that keeps you from getting a surprise when someone flushes the toilet is a pressure balancing valve, one of the greatest developments in modern times, IMO. When someone flushes a toilet or other cold water, the cold water pressure can drop, which then means you get too much hot water in the shower (and vice versa). The pressure balancing is a clever, simple, reliable device that just keeps the pressure of hot/cold even at the shower faucet, just a little piston that freely rotates, opening/blocking the ports to maintain balance.

But it sounds like the OP's problem (along with low temperature), is a limit setting, which simply stops how far the hot handle can go. No feedback, nothing.

There are also ones that actually respond to temperature, though I've never used these.

https://www.cpsc.gov/s3fs-public/5098.pdf

Most adults will suffer third-degree burns if exposed to 150 degree water for two seconds. Burns will also occur with a six-second exposure to 140 degree water or with a thirty second exposure to 130 degree water. Even if the temperature is 120 degrees, a five minute exposure could result in third-degree burns.

A 135F heater will probably be down to 130F at the faucet, a 30 second warning ought to be fine, unless you actually have no sensitivity to that temperature, but then you probaby need to take all sorts of precautions.

-ERD50

 

[ERD50]

I volunteer doing maintenance at a retreat center and all I can say is that those anti-scald valves constantly give us issues as you describe. Due to lawsuits, we can't turn up the hot higher than 120 or so, so we have to tell the cold shower complainers to just buck up and take it. AKA, that exactly describes your problem.

I won't tell you to buck up and take it unless you want me to.

It would seem that with 120F at the heater, you wouldn't need an anti-scald valve at all?

Would someone really stand under a 120F shower long enough to burn themselves? How do they keep those people from not sticking forks in their eyes and ears?

-ERD50

 

[JoeWras]

It would seem that with 120F at the heater, you wouldn't need an anti-scald valve at all?

At home, I don't think so.

In a commercial setting? You still need the valve.

 

[ExFlyBoy5]

Thanks for all the info, I appreciate it. The plumber happens to live in our neighborhood (and owns the company), so he's going to come take a look at it tomorrow and see what he might figure out.

Or you could go old school and have two separate valves -- one hot, one cold -- and do your own mixing. That's what we have, and the temperature is always exactly the way I want it. We have the same set up on the sinks. I really dislike showers/spigots with a single, mixing valve. And I haven't scalded myself yet.

In a perfect world, that is what we would do. However, we have already torn out the wall once and this valve also controls three different outputs. It's way more complicated than it should be.

A tank water heater won't run for hours on end if set to high, as once it heats up the heat stays in the tank for a long time, and just needs the occasional more heating to keep the temp super hot.

But the bathroom sink is getting hotter water, so the problem is not the tank setting.

Why do you have an anti-scald valve (this seems to be the issue to me).

Anti-scald valves have been around for a while and I don't think you can get a shower mixing valve without one.

We use a water recirculator to make hot water available quickly, otherwise it takes almost 5 minutes to get water back to the master bath. The original plans called for two water heaters, but only one was installed.

I was at kid's rental this past weekend. HW tank was set to max temp, and it ran a lot...even though it was middle of night and no one using.

So I set the temp down a notch or so, and it was obvious over next day that the gas did not cycle on as much. Their water is still too hot, in my opinion. We keep ours at Low, which means there will never be a scalding injury.

There has been a recent change in that OSHA (I thing) recommends keeping water (in the tank) at a minimum of 130 degrees to curb legionnaire's disease. The temps I shared was from a infrared scanner, so the temp may not be exactly correct (seems close though, it is pretty close to our pool temp when compared to the automation temperature). 120 does seem low to me since we have both elements set at 75% of max.

Been a few years, but isn't there a knurled wheel that you can lift off and reset at the valve? not just turn the wheel within it's limits?

Not that I could tell. If I remove the limited (bottom part of assembly) then the top portion that the adjusting handle attached to will not engage in the main assembly.

 

[Just_Steve]

This is how to adjust a Kohler.

 

[ExFlyBoy5]

This is how to adjust a Kohler.

Yep, Youtube is awesome. There are probably hundreds of these videos but none address my issue.

 

[JoeWras]

There has been a recent change in that OSHA (I thing) recommends keeping water (in the tank) at a minimum of 130 degrees to curb legionnaire's disease. The temps I shared was from a infrared scanner, so the temp may not be exactly correct (seems close though, it is pretty close to our pool temp when compared to the automation temperature). 120 does seem low to me since we have both elements set at 75% of max.

Zowie. Thanks for the heads up on that.

There was a big outbreak of Legionnaire's at a regional fair in Western NC last month. The hot tub display was implicated. Many sick and at least 4 dead.

 

[ExFlyBoy5]

Zowie. Thanks for the heads up on that.

There was a big outbreak of Legionnaire's at a regional fair in Western NC last month. The hot tub display was implicated. Many sick and at least 4 dead.

I saw that. 142 folks fell ill...talk about a bad deal!

 

[Bamaman]

Most of the Legionnare's Disease comes from water that's stalled in pipes.

For example, hospitals move walls all the time, and they cap off the water lines instead of removing them. The virus grows in the non-moving water and leaches out into the rest of the water system infecting people. The VA Hospital in Houston has had many deaths, and they're working hard taking samples to run to a lab from all over the hospital--constantly.

Most people with hot tubs now have ozone generators which help the chemicals work. And many just use "starter" in their tubs all the time which is like a heavy dose of chlorine.

 

[ncbill]

Most of the Legionnare's Disease comes from water that's stalled in pipes.

For example, hospitals move walls all the time, and they cap off the water lines instead of removing them. The virus grows in the non-moving water and leaches out into the rest of the water system infecting people. The VA Hospital in Houston has had many deaths, and they're working hard taking samples to run to a lab from all over the hospital--constantly.

Most people with hot tubs now have ozone generators which help the chemicals work. And many just use "starter" in their tubs all the time which is like a heavy dose of chlorine.

Yep, I'm not worried about Legionnare's Disease in my home water heater (set to ~125ºF)

 

[Jerry1]

FWIW, 120F sounds low to me for a hot water heater setting.

I get 120 at my kitchen sink and there no way I can keep my hand under it. I think 120 is pretty hot, but I guess it’s and individual thing.

I would have the plumber come back and check it out, maybe he installed a faulty valve, typically those valves are preset to ~105 but have a 120 degree upper limit.

Yep, call the plumber. You already paid the bill, he should make it work or confirm that it’s not going to get any hotter. In which case, I’d ask about a different valve. Mine was installed about three years ago and it can be adjusted to a pretty hot shower. I’ve never measured it. But, maybe they’ve regulated them down since then. In that case, there will be a market (ebay) for the older ones.

 

[ExFlyBoy5]

I get 120 at my kitchen sink and there no way I can keep my hand under it. I think 120 is pretty hot, but I guess it’s and individual thing.

120 is plenty hot and I would be tickled to get that at the shower (or even 110).

Yep, call the plumber. You already paid the bill, he should make it work or confirm that it’s not going to get any hotter. In which case, I’d ask about a different valve. Mine was installed about three years ago and it can be adjusted to a pretty hot shower. I’ve never measured it. But, maybe they’ve regulated them down since then. In that case, there will be a market (ebay) for the older ones.

He's coming out this AM. DW will get to deal with him while I hang out with the dentist. I am not sure who has the better deal?

I told my DW that if this one can't be adjusted, I want something from 1972...I don't need no sticking limiters!!!

 

[JoeWras]

I told my DW that if this one can't be adjusted, I want something from 1972...I don't need no sticking limiters!!!

Good luck finding it. Maybe at a garage sale.

There are federal laws in place that prohibit the sale of various plumbing fixtures. For toilets, it is all about the flow. For faucets, it started with the flow, and most recently was all about zero lead. Yet another reason they are full of plastic crap. I guess it is OK to drink all the stuff that plastic throws off, better than lead?

If you try to return an old faucet to Habitat Restore, for example, they have regulations clearly marked as to what they can take, i.e. only something very recent.