Water Circulation Pump Questions

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Tylerfott

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I currently have a water circulation pump that runs continuously. My system has a dedicated return line but the original plumber has some fixtures fed from the hot line and some from the return line. Not sure if that is normal but it is how it was originally plumbed. The issue I am having is with a 50 gallon tank I am completely out of hot water within about 13 minutes of starting the shower(Luke warm at best by this point) on top of this issue, if I take a very quick five minute shower, within a few minutes of turning the water off, the next person can turn another shower on and the water is significantly lower in temperature. Is this a by product of the continuously running pump. If so what options do I have to address this?
 

Twowaxhack

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What’s the temp of your cold water ?

What’s the temp of your hot water ?

What type water heater do you have ? Gas tank, tankless or electric tank?

If it’s a tank type, what size tank is it ?
 

Tylerfott

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Average cold water temperature at the faucet fluctuates throughout the year depending on weather but I am pretty far out from serving station so this time of year it averages about 55 F and the electric tank water heater is set to 140F and it is a 50 gallon tank
 

Tylerfott

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Your bottom element may not be firing.
Not saying that’s not a possibility but it has been a problem from day one and two different hot water heaters. The current one is brand new. If I close the return line and turn the pump off it works like normal with very long showers you just have to wait a long time for hot water to reach the fixtures.
 

Twowaxhack

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Install a check valve in the pump return line. Make sure the direction of flow is correct.

If you have a check valve it may not be working properly. With the pump running continuously 24/7 a check valve isn’t suppose to be required but I’ve found with high water pressure and/or a pump that’s either not pumping to capacity or is just small without a check valve can allow back flow from the bottom of the heater, where the dip tube conveys the cold water filling the tank.

Your pump may contain a check valve.

You turning off the pump and closing the return and things working properly leads me to this conclusion. It would’ve been good if you included that info in your original post.
 

Twowaxhack

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The hot water outlet and it’s piping is more restrictive than the return line with the pump running. Backfeeding can occur if there no working check valve.

The cold water is taking the path of least resistance and backfeeding through the hot water return.

You could turn the cold water off to the water heater and unplug the pump. Leave the return stop valve on…..

Now go to a hot water lavatory faucet and bleed the hot water pressure down to zero…..if the water never stops then you have a cross connect between hot and cold that’s only showing up on certain occasions….
 

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