New/Modern one handle shower handles

Do they have regulators built-in that only allow X amount of hot water so as not to cause scalding?

The water in the kitchen and both bathrooms will still get scalding hot, but it seems as though the shower is struggling now that the temps are getting cooler. There doesn't appear to be any leaking plumbing anywhere.

Just thought I'd ask before I call a plumber out.

There is usually a disc behind the handle on modern ones that is splined and limits travel to the hot side.  Installed straight up matching the corresponding housing and you get full hot.  Pull handle to look

On the majority of them if you take the handle off there is a little wheel where you can adjust the mix hotter or colder. On mine you pull the plastic wheel out to move it.

That doesn't sound like a valve regulator problem. That sounds like a pipe insulation problem. 

New house?  Is this your first winter in the house?

So, you didn't change anything, but you are now noticing a performance difference in the shower only, right?

I'm betting the shower is further from the water heater than the other fixtures, and that you have exposed piping in the crawl space or attic which is now exposed to colder temperatures, and lacks appropriate insulation.  

Grab a flashlight, and go for a crawl.

Whoops, if a mod could move to OT, didn't mean to post here (too many windows open).

Slab house (built in '84 was completely remodeled before we moved in, to the point of new cable wiring in every room), first winter, in my part of the country 99% of the time the pipes are poured in with the slab. 

It still gets warm, just not as warm as it did. The faucets in the bathroom (separate hot and cold) just a few feet away still get blazing, scalding hot. 

I'll see if I can pull the handle today when I get home from work.

I was wondering... lol. I was like “what forum is this? Bob vila?”

Yup, most have the anti-scald feature which sounds good until you use it the first time. Then you reset it to allow the max hot.

Every modern shower valve I have purchased recently has had anti-scald technology built in.  Never knew that you could adjust it though, mine are just set at whatever it is.

RossD said:

Yup, most have the anti-scald feature which sounds good until you use it the first time. Then you reset it to allow the max hot.

Yeah, hoping a mod will see and move to OT. 

Whoops!

Because of where it was I was thinking you wanted to use them on a build as like door pulls or something

RossD said:

Yup, most have the anti-scald feature which sounds good until you use it the first time. Then you reset it to allow the max hot.

Yep, anti-scald in my world = anti-happy old lady customers.  After 2x setting them not at full bore and having to go back even though I thought it was way too hot, I have set them straight up to no limit since. Never had anyone complain that the water gets too hot.  

Thanks everyone, I'll give it a look when I get home. 

I'm not handy IN THE SLIGHTEST when it comes to home stuff.

The nearby scalding sink makes me reconsider my response, but I would definitely not assume the pipes are in the slab. 

Most areas that build on slabs have converted to putting water lines above the floor. Drain lines are in the slab, but water lines are often overhead. 

Any  Builder who is had to pay for repairs to a house that had a water line leak under the floor, will never put waterlines under a slab again. 

SVreX said:

The nearby scalding sink makes me reconsider my response, but I would definitely not assume the pipes are in the slab. 

Most areas that build on slabs have converted to putting water lines above the floor. Drain lines are in the slab, but water lines are often overhead. 

Any  Builder who is had to pay for repairs to a house that had a water line leak under the floor, will never put waterlines under a slab again. 

Pretty much status quo here still.  Lay pipes in kinda sorta the right place, pour concrete poorly around them, frame where the framing was supposed to be originally instead of moving it a half inch, then bulge the drywall around the pipe that’s 1/2” outside the framing.  

when I moved some years ago, i took my old single handle with me to avoid the anti scald stuff!

Sounds more like you have a tankless water heater on your boiler.  In the winter they can't make hot water as well as they can in the summer due to incoming cold water temps.  Domestic hot water is suppose to max out at 126*.  Shower temps are suppose to Max out at 112*.  Therefore shower valves are suppose to be a single handle, pressure balance design with provisions rto limit high temps down to 112*  outoing max temperature has a direct relation to incoming water temps.  In the Winter, cold water is colder, hot water isn't as hot, shower is not as hot.  Some shower valve nmanufactures have special internals just for houses that use a tankless water heater.  Symmons is a perfect example.  Standard diverter/mixing part of valve has 5 holes for cold water.  Tankless model only has 3.  Hence its called a 3 hole diverter.  It allows less cold water into the valve to begin with so the hot can better do its job.  Try adjusting the limit on the shower valve first like everybody above suggested.  If its already maxed out, you may be able to buy parts for the valve to compensate.  You can also install a ball valve on the cold and partly throttle it closed to achieve the same effect of limiting the cold water going into the valve.  Sadly, if you do have a tankless and thats the problem, its only going to get worse as that thing gums up and doesn't absorb the heat from the boiler as well as when it was new.  Changing those things really sucks.  Had to do one last week.

SVreX said:

The nearby scalding sink makes me reconsider my response, but I would definitely not assume the pipes are in the slab. 

Most areas that build on slabs have converted to putting water lines above the floor. Drain lines are in the slab, but water lines are often overhead. 

Any  Builder who is had to pay for repairs to a house that had a water line leak under the floor, will never put waterlines under a slab again. 

Sorry Paul it's just they way they build houses around here. I did construction work in college, for a concrete company, and still drive by the occasional new edition (like what I was considering buying in earlier this year)....in OK, it is SOP to put all the pipes/drains in the slab. 

If one starts leaking, they do a reroute through the attic. Paid for numerous of those working at State Farm as well. And it's typically not until decades after the home was built, so the builders aren't responsible.

Didn't get a chance to pull the handle last night, bosses boss is in town this week so last night was the old "dinner and drinks" on the company.

tr8todd said:

Sounds more like you have a tankless water heater on your boiler.  In the winter they can't make hot water as well as they can in the summer due to incoming cold water temps.  Domestic hot water is suppose to max out at 126*.  Shower temps are suppose to Max out at 112*.  Therefore shower valves are suppose to be a single handle, pressure balance design with provisions rto limit high temps down to 112*  outoing max temperature has a direct relation to incoming water temps.  In the Winter, cold water is colder, hot water isn't as hot, shower is not as hot.  Some shower valve nmanufactures have special internals just for houses that use a tankless water heater.  Symmons is a perfect example.  Standard diverter/mixing part of valve has 5 holes for cold water.  Tankless model only has 3.  Hence its called a 3 hole diverter.  It allows less cold water into the valve to begin with so the hot can better do its job.  Try adjusting the limit on the shower valve first like everybody above suggested.  If its already maxed out, you may be able to buy parts for the valve to compensate.  You can also install a ball valve on the cold and partly throttle it closed to achieve the same effect of limiting the cold water going into the valve.  Sadly, if you do have a tankless and thats the problem, its only going to get worse as that thing gums up and doesn't absorb the heat from the boiler as well as when it was new.  Changing those things really sucks.  Had to do one last week.

Not a tankless water heater. It's a 40-50 gallon standard that works great. 

House was a fire loss that didn't burn down, flourescent light ballast caught fire in the attic and smoldered the contents. Smoke damaged the entire house. So everything from the windows, to the flooring, paint, cabinets, granite, roof, fixtures and ALL the mechanicals are brand new. 

So I get the advantage of a new home, inside funky early 80s architecture on a corner lot.

Take the handle and face plate off the valve and have a look inside the valve.  One way or another you can adjust the high temp limit.  As you open the valve, only cold passes thru the mixing valve.  The farther you spin the handle the less cold it allows in and the more hot is allowed to enter.  Turn it far enough and you basically get only hot.  The limit screw or cogs are there so that the user can only spin it far enough to get 112* and it is suppose to be set by the installer.  Check temp on your water heater and make sure its at least 120* and then play with the valve.  You can always turn the water heater up a tad, but you run the risk of scalding.  Problem with the cog style of adjustment is the range in temps between cogs.  Not uncommon to get 108 at one tooth in the cog and 114 at the next.  Some of the newer valves with cogs also have a set screw to make finer adjustments.  Suppose to use a good thermometer to adjust temps, but the back of your hand works well.  FWIW, my tub and shower valve will deliver full 140* water, just had to teach the kids early on about hot water.  112* water doesn't stay warm in a Jacuzzi tub long and when you try to add some more hot water 112* doesn't cut it.

On the really simple side you might want to unscrew the shower head.  I had a recent case where both flow and temperature changed gradually over time.  Took the shower head off and turned water on and it was clear there was plenty of volume and temperature without the shower head.  A good CLR soaking and everything was back to normal.  I was surprised that it also impacted the temperature but it did.  Your comment about scalding hot in the same room at the sink and the gradual change made me bring this up.

I'm still surprised we don't see some sort of conduit in slabs that they can push pex through from a utility room to each water using room. Probably not code approved.

Second the clean the shower head plan, had to do it myself last weekend.

I haven't had a chance to mess with this yet, but do you really think the shower head would start clogging in less than 3 months of use?

Remember, everything in the house is brand new.