New hot water heater - temperature differential too big?

My new Bradford-White water heater is set to 132. The upper limit works fine, it shuts off right at 132. That is fine. However, during the night, the temperature might drop as low as 115. Happens occasionally during the day, too, probably when I don't run enough hot water to cause the thermostat to kick in (at 114-115).

Of course, taking a shower in the AM causes the burner to begin to heat it back up to 132. But---several people might need to take a shower starting with a tankful of 115-degree water.

My old heater kept the temperature much closer.

It has the Delta 650 gas valve.

Is this too much of a temperature drop? Seems like it to me.

Thank You,
Vicki

Ball B/W. That seems a little out of range. Gas valve might be bad.

I have had several Robertshaw valves and they were completely reliable. Do you know if this Delta valve often has problems? I can find almost nothing on the internet about it.

Also, can you tell me what range you would typically expect to see?

Thanks, Vicki

I think it is the thermostat and not the gas valve

In response to your question, "...what range you would typically expect to see?"

http://waterheatertimer.org/How-water-heater-thermostat-works.html
The following info regarding differential temperatures(stop and start temps) was taken from the above referenced site.
"...differential of water temperature before water heater turns on. For example, thermostat is set to 120° and tank is fully heated. Hot water is drawn for bath. How LOW will the water temperature get before the water heater turns ON? Answer: calibration range for thermostat can be around 10-20%. On gas water heater, 'water temperature around the thermostat probe can drop 15-25°F before main burner is activated.' Water at bottom of tank can be 95° and top of tank still be near 120° thermostat set point.
If differential is greater than 20%, the thermostat should be replaced.
Other things affect the actual water heater. If a water heater is short cycling, where it turns on-and-off too frequently, it can mean thermostat calibration is too narrow, however thermostat are not 'fast-acting' and problem can be caused by other issues, such as water leak or stacking,"

Can the thermostat be changed without changing the whole gas valve ?

Diehard, I read the article you referred me to and this stood out... "First is the actual temperature of water vs the setting you choose. You can set thermostat to 120° and water temperature might be 115° or 125°. However, a wide temperature differential between setting and actual water temperature can mean thermostat needs to be replaced."

That gives me a sense of what should be expected. If I had a 5 degree swing each way, between 137 and 127, I would be thrilled, and you guys would not be having to answer my dumb questions. I try to fix most everything myself. If I have to call someone in (it happens), I like to have a pretty good idea of what is wrong.

Vicki

That's not the swing in temperature you were talking about initially.
You were talking about the 132 off setting to a drop to 115 as the on setting. That is the differential. Based on that article the a 10 to 20% difference is probable before it turns on again.
10 to 20% of 132 degrees is 13.2 to 26.4 degrees.
So a drop from you 132 off point to your ON point can be up to 132 - 26 = 106 degrees. And they say, "If differential is greater than 20%, the thermostat should be replaced." Yours was only 13% or 17 degrees less.

The 115 or 125 was the fluctuation of the OFF setting.