I had a new GE 40 gal gas water heater installed, replacing an old unit.
We noticed right away that the water temperature in the shower often needs adjustment when we step in the shower (after the water has been running for several minutes to allow for cold pipes). The temp is set fairly low to avoid wasting a lot of hot water. The water coming from the shower head, after I let it run for 4 minutes, shows between 95 and 105 degree, a 10 degree differential.
Is this normal? I am glad my furnace thermostat is more accurate than that.
40 gallons of water is not going to vary 10 degrees in 4 minutes no matter how bad or good the thermostat is. I would look for other causes in your house.
Do you mean shower water temp drops from 105-95 after 4 minutes, are both thermostats actualy kicking in at the same temp if you test them on a stabilised tank temp, so if you lower then raise each thermostat you can tell if they both are heating to the right temp. Maybe one element is not heating to the same temp. Or a dip tube issue, im guessing im no water heater pro.
What I meant was: I let the hot water run at the shower for 4 minutes to make sure it will be as hot as it will get. It takes that long to get hot water at the shower from the water heater because the pipes are cold.
It may be. Lets look at the whole picture. When you start the shower, the water is coming from two sources, the water heat that is perhaps 125 degrees, and the cold water that has been sitting in the house at perhaps 68 degrees. You blend the two together to get water that is 105 or so.
After the shower runs for a time, the water in the pipes gets used up. To replace it, the water comes in from the outside. If you live in the south, it may be 60 degrees. If you live in the north, it may be 45 degrees. The ground is very cold right now. Blend that with what is in the heater and you need to make adjustments. If the water tank is already set very low, it is difficult to make up that difference.
While you think you may be saving money keeping the temperature set very low, it may be costing more in the end as you need more of it to get the same job done. Set it up to about 125 to 130 and see what happens. You may be much happier and still be very economical. You needs less of the heated water to get the same comfort level. In any case, you'll have to make adjustments when the street or well water hits the shower head.
If I understand correctly, I have the same problem. This is my 5th water heater in this house in many, many years. This one and the last one behave as follows: For the 1st shower in the morning, after setting all night, you have to use very little cold water. While you are showing, the water heater fires up (note gas) and the water gets warmer. You then have to add more cold to compensate. I have pressure balanced valve on both showers, however, pressures don't change, only the hot water temperature. I heard somewhere, maybe on this group, that the newer gas heaters are set up to "float" with the usage. This is supposed to reduce heat loss, or something like that. BTW, all day, when water is being used (2 retired people), it stays at the higher temperature. It only to gets cooler when you there is no usage for a bunch of hours. I have the water heater set to the recommended setting which is not anywhere near the highest setting. Maybe if it were set to a higher setting, you wouldn't notice it as much. Any comments? Art
I have noticed the same thing, when I moved into my house the first shower of the day was never hot enough, but if you were second in line you got a nice hot one. I eventually just raised the tank temp, you still have to adjust a little, but at least everyone gets a hot shower.
After all that the OP has said, I'm still not sure exactly what's going on.
" The water coming from the shower head, after I let it run for 4 minutes, shows between 95 and 105 degree, a
10 degree differential. "
"What I meant was: I let the hot water run at the shower for 4 minutes to make sure it will be as hot as it will get. It takes that long to get hot water at the shower from the water heater because the pipes are cold. "
Is he saying it takes 4 mins to get from 95 to 105 and then stays there? Or that it does that first and then varies by some unspecified amount? If you can't state the problem, you aren;t likely to get an answer.
Did the installers actually install the dip tube? It's a $5 plastic tube that goes in the cold (supply) side & takes incoming cold water all the way to the bottom of the tank. If it's not there, the cold water mixes with the hot water right at the top of the tank.
old tanks had poorer insulation, so the temp would drop and burner come back on to reheat.
new tanks have much better insulation with really low standby losses:)
The price is temperature falls slowly, tank never gets cold enough to reheat by morning.
try running some hot water right before bedtime, so the tank reheats. insulate lines to tank etc to minimize standby losses. thus minimizing the drop.
manufacturers could design better thermostasts that hold the temperature closer, but they would cost more.
soon none of this will matter once tanks come from china, price will be so cheap no one will care
The newer gas water heaters also have a higher temperature differential thermostat as an energy saving feature. The water has to get colder before the burner lights so the water is quite a bit hotter just after the burner goes off than it is just before the burner relights again. When you first start using water, the temperature can be anywhere between those points, depending on how long it has been since the burner went off or on. A minor but noticeable annoyance to me.
Also, many faucets now have anti-scald crap in them that will always mix a little cold water even when you have it set to full hot. That could complicate this whole problem. I've removed them from my lav faucets.
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