Mixing Valve Question

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ftres

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I am in New York on Long Island.
I have a mixing valve on the hot water output of my hot water tank.
I have a natural gas fired Burnham ES2 and a Burnham 50 gallon indirect storage tank.

I keep the setting on the hot water tank to maintain 160 degrees with a 10 degree differential.
The mixing valve is set to output 125 degree water.

Here's my question. In the summer when I'm not running the boiler to heat the house, does it cost more to keep the tank temperature at 160 and use the mixing to lower the temperature, or should I lower the tank temperature back down to 125 and bypass the mixing valve (I have bypass valves to cut it out)?

At first thought, it seems obvious that it would cost more to keep heating the water to 160 rather than 125, because the boiler needs to fire more often to keep the water hotter.
But is that really true, since with the mixing valve inline, I'd be using the hot water up at a slower rate, so that should cause the water to need to be heated less often?

Are there any other reasons to use the mixing valve or not all year round?
 
As a general rule, the more the system can put out(potential energy), in a set amount of time, the more energy is required. Separate from the standby loses of the storage tank. So it seems to me, without trying to calculate it, that it would be worthwhile to reduce the tanks storage temperature to the required final temperature, so long as it can be closely maintained.

Don't those storage tanks have something called "Proprietary TPI control accurately controls the output water temperature and helps eliminate tank overload."
Do you have a separate mixing valve in addition to the tanks temperature control?
I'm really not familiar with the system, but just looked it up and saw this "Proprietary TPI control ".
 
As a general rule, the more the system can put out(potential energy), in a set amount of time, the more energy is required. Separate from the standby loses of the storage tank. So it seems to me, without trying to calculate it, that it would be worthwhile to reduce the tanks storage temperature to the required final temperature, so long as it can be closely maintained.

Don't those storage tanks have something called "Proprietary TPI control accurately controls the output water temperature and helps eliminate tank overload."
Do you have a separate mixing valve in addition to the tanks temperature control?
I'm really not familiar with the system, but just looked it up and saw this "Proprietary TPI control ".

Yes, the tank has a TPI control. But I frequently don't have enough hot water for the 6 people who live in my house. So I added the mixing valve hoping to get "more hot water" out of the tank.
But we tend to only not have enough from the tank alone in the winter months. In the summer, the tank alone is mostly adequate.

So just wondering if it pays to bypass the mixing valve during the summer. I'm looking for professional opinions on the matter.

Thanks.
 
Yes, the tank has a TPI control. But I frequently don't have enough hot water for the 6 people who live in my house. So I added the mixing valve hoping to get "more hot water" out of the tank.
But we tend to only not have enough from the tank alone in the winter months. In the summer, the tank alone is mostly adequate.

So just wondering if it pays to bypass the mixing valve during the summer. I'm looking for professional opinions on the matter.

Thanks.
A bit confused with this answer. Sounds like you have already done it.
If it pays is difficult to answer. Based on your statement, "In the summer, the tank alone is mostly adequate.", I'd say just reduce the TPI temperature setting to a point where you find it TOTALLY adequate for the summer months while still using the mixing valve. That would save you some energy cost while maintaining adequate hot water at acceptable temperature.
If you're just looking for professional opinions you're likely to get different ones.
 

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