Water heater tank recirculation pump?

[Melissa2007B]

I've mentioned here before, that we have a stacking problem because of the whole house humidifier taking tiny bits of hot water off the top.

So I'm looking for a water heater tank recirculation pump. I'm not talking about the ones that send it in a big loop around the house - JUST from the top of the tank to the bottom, constantly.

Can anyone tell me what they're called, and how I differentiate them while doing a web search, so I don't just see the ones that loop it around the whole house?

Thanks!

 

[Jadnashua]

You'd need a pump with either bronze or SS body since it's on potable water, otherwise it would rust out quickly. You'd also need a checkvalve and maybe a volume control valve to limit the flow. If you used a 24vac control relay, and it was tied into the humidifier, it would only need to run when the humidifier was running.

 

[Sponsor]

 

[Melissa2007B]

May as well run it all the time, but what do they call this? It just needs to go in on top and circulate water from the bottom.

 

[Jadnashua]

I'm not sure you'll find one made specifically for this purpose. ANd, if you ran it all of the time, when you were using hot water, say for a shower, pumping water from the top to the bottom would mean you'd end up with much less useful hot water. Better to limit it to only when the humidifier runs, or switch to using cold water at the humidifier with only a minor decrease in efficiency. Probably save a lot of money, and much less complication.

 

[Smooky]

It is not a pump. It is called a thermostatic mixing valve or hot water mixing valve or master hot water mixing valve .

https://terrylove.com/forums/index....c-mixing-valves-water-heater-tempering.45651/

https://www.google.com/search?q=hot water mixing valve&biw=1280&bih=553&source=lnms&tbm=isch&sa=X&sqi=2&ved=0CAcQ_AUoAmoVChMI4OfVt7r-yAIVEN5jCh1sGAQd#imgrc=_

 

[Reach4]

I've mentioned here before, that we have a stacking problem because of the whole house humidifier taking tiny bits of hot water off the top.

Are you thinking that because the T+P valve is dribbling?

If so, you may need a thermal expansion tank because there is something preventing expanding heated water from feeding back to the city water. This could be a check valve or a pressure regulating valve. The T+P sees 150 PSI and releases water to limit the pressure.

 

[hj]

ANY pump will do the job. The difference between what you want and a "whole house" pump is in how they are connected and wired.

 

[Melissa2007B]

I'm not sure you'll find one made specifically for this purpose. ANd, if you ran it all of the time, when you were using hot water, say for a shower, pumping water from the top to the bottom would mean you'd end up with much less useful hot water.

That doesn't seem to make sense. If it circulates water in the tank all the time, the tank water would all be at whatever temp I set the thermostat to, which is good. Right now, it's all over the place, depending on whether the humidifier is running, and it's getting WAY too hot at times, to where we're getting gray hot water sometimes, which appears to indicate that the bottom of the tank is being rapidly eroded by the excess heat. This scares me, because we just replaced it about 4 years ago and it was $1000.

Better to limit it to only when the humidifier runs, or switch to using cold water at the humidifier with only a minor decrease in efficiency. Probably save a lot of money, and much less complication.

The humidifier is an Aprilaire 360 and is spec'd at 140 degree water and I've tried lowering that, but it uses a lot more water and doesn't work well.

 

[Melissa2007B]

It is not a pump. It is called a thermostatic mixing valve or hot water mixing valve or master hot water mixing valve .

https://terrylove.com/forums/index....c-mixing-valves-water-heater-tempering.45651/

https://www.google.com/search?q=hot water mixing valve&biw=1280&bih=553&source=lnms&tbm=isch&sa=X&sqi=2&ved=0CAcQ_AUoAmoVChMI4OfVt7r-yAIVEN5jCh1sGAQd#imgrc=_

NO, I'm talking about some kind of low wattage pump, to take water from the bottom of the water heater tank and circulate it to the top, continuously, so we don't get the extreme heat that the humidifier is causing by taking a trickle off the top.

 

[Melissa2007B]

Are you thinking that because the T+P valve is dribbling?

If so, you may need a thermal expansion tank because there is something preventing expanding heated water from feeding back to the city water. This could be a check valve or a pressure regulating valve. The T+P sees 150 PSI and releases water to limit the pressure.

NO, because the water gets way too hot when the humidifier runs for awhile, and we've been seeing gray in the hot water, indicating that the tank may be rapidly eroding from this "stacking" effect. And when the humidifier is off for a long time, the hot water temp is too low, because I have to keep it set too low to prevent overflowing. We REALLY need a constant circulating pump within the water heater tank itself.

 

[Reach4]

NO, because the water gets way too hot when the humidifier runs for awhile, and we've been seeing gray in the hot water, indicating that the tank may be rapidly eroding from this "stacking" effect. And when the humidifier is off for a long time, the hot water temp is too low, because I have to keep it set too low to prevent overflowing. We REALLY need a constant circulating pump within the water heater tank itself.

How about pulling the humidifier water from the bottom of the WH? The thread on the drain valve is regular 3/4 NPT thread. You could use a brass nipple or dielectric nipple, a tee, and put the drain valve on the tee also.

 

[Melissa2007B]

ANY pump will do the job. The difference between what you want and a "whole house" pump is in how they are connected and wired.

It may also require a smaller pump, just to recirculate within the tank. Less wattage and cost? But how to do the looping is something I don't know about. If it had a teflon tube coming out the center of the main outlet, it could be run to the bottom of the tank and just use that one outlet.

 

[Melissa2007B]

How about pulling the humidifier water from the bottom of the WH? The thread on the drain valve is regular 3/4 NPT thread. You could use a brass nipple or dielectric nipple, a tee, and put the drain valve on the tee also.

The cold water comes in at the bottom. I really don't see any way to fix this, without a recirculating pump within the tank.

 

[Reach4]

The cold water comes in at the bottom. I really don't see any way to fix this, without a recirculating pump within the tank.

Does the tank have a drain?

This is a newer waternheater, but it is the same model with the same problems, right? Your symptoms are not common to most water heaters.