New Hot Water Heater, Little Hot Water Still

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johnrclark12

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Seems like it was overnight last week that the water pressure in the shower doubled and the length of getting hot water went down nearly 50%. After a 10 minute shower, there was no hot water (Used to go 30+ mins just fine).

Replaced the electric tank water heater because I felt like it was due after having the old one for 10+ years. Hooked it up and made sure all connections were working fine. It appears that the water pressure issue was fixed but the hot water issue is still not fixed. No matter which sink/shower/faucet I use in the house.

I'm only getting about 10-15 mins of hot water. I have to gradually keep turning down the cold water in the shower until there is no cold water on at all, and after that, I have about 20 seconds left. After a 30 minute wait, the process repeats itself again.

Any advice on where to start??
 

Reach4

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Seems like it was overnight last week that the water pressure in the shower doubled and the length of getting hot water went down nearly 50%. After a 10 minute shower, there was no hot water (Used to go 30+ mins just fine).

Replaced the electric tank water heater because I felt like it was due after having the old one for 10+ years. Hooked it up and made sure all connections were working fine. It appears that the water pressure issue was fixed but the hot water issue is still not fixed. No matter which sink/shower/faucet I use in the house.
I suspect I am reading that wrong. Are you saying that you replaced the WH than was working fine? Or are you saying that that you had too much pressure on hot before replacing? Nah, can't be that. Was there any symptom before replacing the WH?

I'm only getting about 10-15 mins of hot water. I have to gradually keep turning down the cold water in the shower until there is no cold water on at all, and after that, I have about 20 seconds left. After a 30 minute wait, the process repeats itself again.
You may have burned out one of the elements by turning on power before the WH was full of water. Alternatively, the WH may have had a bad bottom element or thermostat when it arrived. With a clamp-around ammeter, see if there is current flowing to the WH when the WH is not delivering hot water.

An electric WH normally gives priority to the top element, and then once the top water is hot, power is supplied to the bottom thermostat and element. If you have a lower element failure or thermostat fail, the tank may be sitting there with hot water in the top of the WH, and not-hot below.

A voltmeter may be able to do some troubleshooting, but that clamp-around ammeter can do some more.
 

Terry

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A longer shower can be had if the shower head is restricted to 2.5 gallons a minute would would give you at least twenty minutes even if you only ran hot water from it.
If you using 50 gallons in ten minutes, that's 5.0 gallons a minute. I'm guessing your shower head is letting out even more than five gallons.
 

johnrclark12

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I suspect I am reading that wrong. Are you saying that you replaced the WH than was working fine? Or are you saying that that you had too much pressure on hot before replacing? Nah, can't be that. Was there any symptom before replacing the WH?

The pressure went up BEFORE I replaced the tank. It went back to normal after the replacement. The pressure increase was happening regardless of hot/cold water in the shower. Also, it appears my bathroom sink pressure went DOWN. Odd, I know.

You may have burned out one of the elements by turning on power before the WH was full of water. Alternatively, the WH may have had a bad bottom element or thermostat when it arrived. With a clamp-around ammeter, see if there is current flowing to the WH when the WH is not delivering hot water.

An electric WH normally gives priority to the top element, and then once the top water is hot, power is supplied to the bottom thermostat and element. If you have a lower element failure or thermostat fail, the tank may be sitting there with hot water in the top of the WH, and not-hot below.

A voltmeter may be able to do some troubleshooting, but that clamp-around ammeter can do some more.

I will give this a shot, thank you. I can almost assure you that the tank was likely turned on before it was completely filled since it was only a few minutes after getting everything connected that it was turned on. The only thing I did was make sure the thermostat was set to 120, which it was. I didn't actually test the current since I assumed it would work (being brand new.)
 

Terry

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Often with a new water heater installation, the aerators on faucets can become filled with sediment. I would check the screens on them. I like to run the tub after a water heater install, as it puts most of the grit and grime through the tub spout and saves the faucet aerators.
 

Phog

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Do you have any tempering or thermostatic mixing valves in your plumbing?
 

johnrclark12

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Do you have any tempering or thermostatic mixing valves in your plumbing?

I do not. I have a plumber coming to look at it soon. They told me over the phone the pressure in my town recently went up about 15-20 psi, which explains the pressure increase. He told me that may also be why I am running out of hot water so quickly. He suggested they may end up turning the temp up on the water heater if everything else checks out.
 

Phog

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A change in city water pressure would not explain running out of hot water faster. Unless you are turning the shower handle to its highest flow setting (all the way on). Now that the pressure is increased, "all the way on" gives a higher flow than it used to. You can easily solve this by simply turning the knob only 75% of the way on, so that you get a little less flow out of the shower head.
 

Reach4

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A change in city water pressure would not explain running out of hot water faster. If the incoming water is also a lot colder, it would though.
If it drove more gpm thru the showerhead, it could.
 

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What is the current hot water temp? If only heated to satisfy the temp needed to shower, you are then likely to use 100% hot water to the shower head. By heating above the temp needed, cold water will be mixed with the hot through the shower control so less hot water will be used for each shower.

Electric water heaters are notoriously slow for recovery. Storing a volume of hotter water than needed will be equivalent to a larger storage tank. Because of risk of scalding, water to fixtures is to be no hotter than 120F but the water in the tank maybe hotter if a mixing valve is utilized to blend cold with the water from the WH to supply 120F to faucets and appliances.
 

johnrclark12

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The plumber came yesterday and adjusted the hot water setting on our 40 Gal Water Heater from 118-120 up to 130. He said recently all of their Rheem heaters have been pre-set to the lowest setting for safety reasons. He turned down the main valve from all the way on to about 75% on, and it helped with the pressure a little bit.

The hot water certainly lasted longer after this, but I still feel like there is something else going on. Gradually having to twist the knob towards hot more in the shower isn't something I had to do before.

We have something like this for turning on the water, brand new from Amazon (Installed with the recent hot water tank). So I'm not sure how you can only have it 75% on. You have to twist it 50% to get warm water, and more gradually towards 100% during the shower until its all hot. But like I said before, this is affecting all of our faucets/sinks not just the shower.
 

Bannerman

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120F is the usual standard for safety. The setting dial in the WH is not always accurate so you may want to measure the actual water temp from a faucet using a candy thermometer while hot water continues to run into a coffee mug.

A pressure balancing shower control will not usually control water volume. Flow will be close to 100% regardless of whether Cold, Warm or Hot is dialed. To reduce the water volume to the shower head, some shower heads are equipped with a volume control such as this example:. https://www.amazon.com/Saving-Shower-Button-Control-Chrome/dp/B01HW5AIY8

A separate valve may also be added before your existing shower head. https://www.amazon.com/APLusee-Pressure-Regulator-Adjustable-Universal/dp/B07RK25JNV

Unless the pressure balancing shower valve is defective and allowing hot and cold water to mix all the time, the shower control should not effect the hot water temperature flowing from other faucets.
 

Sarg

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Just to support the plumber's thought ==== After I installed a new Rheem Electric in November I initially thought something was wrong. I increased the temp to just over 125 degrees and we've been happy since.
 
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