Lowest cost way to circulate water within water heater tank?

Users who are viewing this thread

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
Of the available insulation products, closed cell is up there in quality...better than fiberglass and many other items, at least in R-factor/installed inch.
 

Melissa2007B

Member
Messages
369
Reaction score
9
Points
18
Location
Denver, CO
Of the available insulation products, closed cell is up there in quality...better than fiberglass and many other items, at least in R-factor/installed inch.

I just need a definitive idea of whether breaking into the plastic and insulation under there, to do this, would cost us in energy efficiency of the house itself.
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
Depending on where the lines are run, adding more insulation may not buy you much. Ideally, they're above the insulation next to the subflooring, and while a foam jacket would help, it may not be worth the effort to tear things apart to add it. Adding insulation between the heated area and the pipe could be counter productive, as it might keep heat from the house from the pipes, but your floor probably never gets cold enough to freeze things! Not sure you'll ever get a definitive answer. If you decide to add a hot water recirculation system, compare your utility costs before and after. If they rise more than you want, then, consider adding insulation. The electrical cost of actually pumping the water is small, most of the pumps are in the order of 1/28th HP, maybe 30W, and depending on how hooked up, may not run much. The unit I have turns the pump on/off as needed. Some run it continuously. Mine tends to only run about 45-seconds 3-4x per hour when the timer allows it (it gets shut off at night). The first time it turns on in the morning, it might run twice that long or so.
 

Melissa2007B

Member
Messages
369
Reaction score
9
Points
18
Location
Denver, CO
Depending on where the lines are run, adding more insulation may not buy you much. Ideally, they're above the insulation next to the subflooring, and while a foam jacket would help, it may not be worth the effort to tear things apart to add it. Adding insulation between the heated area and the pipe could be counter productive, as it might keep heat from the house from the pipes, but your floor probably never gets cold enough to freeze things! Not sure you'll ever get a definitive answer. If you decide to add a hot water recirculation system, compare your utility costs before and after. If they rise more than you want, then, consider adding insulation. The electrical cost of actually pumping the water is small, most of the pumps are in the order of 1/28th HP, maybe 30W, and depending on how hooked up, may not run much. The unit I have turns the pump on/off as needed. Some run it continuously. Mine tends to only run about 45-seconds 3-4x per hour when the timer allows it (it gets shut off at night). The first time it turns on in the morning, it might run twice that long or so.

Given the stacking problems, it sounds best to run it all the time. Our crawl space has been insulated on the side walls, and the vents have been sealed, so the temp down there feels like about 60 - a little cooler than the house but not that much.
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
If you run a dedicated pump just to prevent stacking, that also means while using the water for say a shower or filling a tub, you'll be constantly 'wasting' some of the hot water by dumping it into the now cold bottom of the tank rather than going to your point of use. To make that work well, you'd want a flow sensor to shut off the pump while there is a draw.

Even with recirculating system meant to get hot water to your points of use, in general, the water doesn't actually constantly flow. That would be quite an energy hog. While the pump itself may constantly run, there will be temperature controlled valve in the system that will open and close to allow the water to flow or not that tries to maintain some certain temperature at those points of use. Mine just happens to shut off the pump, and therefore doesn't use any energy once it detects warm water at the point of use (typically, the furthest distance from the WH so everything closer is also warm with most common layouts...doesn't always work without extra stuff depending on how yours is laid out). Lots of companies make these things...the one I have is made by RedyTemp, and, because I had an outlet under the sink in my master bathroom, took all of about 10-minutes to install with only a wrench. It's by far the easiest to install, but not the least expensive to buy (depends on if you're capable of installing the others, and if not, the labor might make them more expensive).
 

WorthFlorida

Clinical Trail on a Cancer Drug Started 1/31/24. ☹
Messages
5,727
Solutions
1
Reaction score
982
Points
113
Location
Orlando, Florida
Melissa2007B

If you really need warm water for the humidifier, install a 2.5 gallon point of use water heater. They run on 120v's so it makes the install easy. That eliminates your temp fluctuation problem. The few months that you need the humidifier the cost of an electric water heater would be hardly noticeable. When your heating season ends, switch off the water heater.

As far as getting hot water to that distant shower take Jadnashua's advice.

Actually, in South Florida, the groundwater is the average mean air temperature for one year, 75 degrees. It also picks up heat from the ground since the water meters are at ground level near the sidewalks.
 
Last edited:

Melissa2007B

Member
Messages
369
Reaction score
9
Points
18
Location
Denver, CO
Melissa2007B

If you really need warm water for the humidifier, install a 2.5 gallon point of use water heater. They run on 120v's so it makes the install easy. That eliminates your temp fluctuation problem. The few months that you need the humidifier the cost of an electric water heater would be hardly noticeable. When your heating season ends, switch off the water heater.

As far as getting hot water to that distant shower take Jadnashua's advice.

Looking into it. The water department is coming over tomorrow to see the black water and take a sample for testing.

Actually, in South Florida, the groundwater is the average mean air temperature for one year, 75 degrees. It also picks up heat from the ground since the water meters are at ground level near the sidewalks.

Yeah, I'm from Miami originally, I know. :)
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
FWIW, the owner's manual says this from page 7:
"Whether to use available tap water, even though it may be quite hard, or chemically softened water, is a common question homeowners have when their dealer is installing a humidifier. Your humidifier is designed to operate effectively using hot, cold, hard or mechanically softened water. (Hot water is recommended for Models 350 and 360.)"

IOW, it will work with cold water coming in, and would be the easiest way to solve the stratification problem. How much better it might work with hot, I do not know, but do know mine works fine with cold going into it.
 

Melissa2007B

Member
Messages
369
Reaction score
9
Points
18
Location
Denver, CO
I had the city water people come over yesterday but they're only concerned with the main water line and cold drinking water, and said that because this is the hot water only, they don't test it. They only test city water for chlorine, which is odd.

But I'm checking with independent test labs and the cost is over $200. Ouch.
 

Reach4

Well-Known Member
Messages
38,796
Reaction score
4,412
Points
113
Location
IL
I had the city water people come over yesterday but they're only concerned with the main water line and cold drinking water, and said that because this is the hot water only, they don't test it. They only test city water for chlorine, which is odd.
The reason for testing for residual chlorine far from the water plant is to make sure there is some to prevent bacteria from growing at the outer reaches.
But I'm checking with independent test labs and the cost is over $200. Ouch.
I lost track of what you are testing for, but it is probably in Kit-90 at http://www.karlabs.com/watertestkit/ If you are just testing for hardness, it would be better to get the Hach 5-B test... the lab test is not that much more expensive after considering shipping, but the Hach 5-B gives you repeat DIY tests. You could help your friends. Plus it will be useful to test your new softener output.
 

Melissa2007B

Member
Messages
369
Reaction score
9
Points
18
Location
Denver, CO
The reason for testing for residual chlorine far from the water plant is to make sure there is some to prevent bacteria from growing at the outer reaches.
I lost track of what you are testing for, but it is probably in Kit-90 at http://www.karlabs.com/watertestkit/ If you are just testing for hardness, it would be better to get the Hach 5-B test... the lab test is not that much more expensive after considering shipping, but the Hach 5-B gives you repeat DIY tests. You could help your friends. Plus it will be useful to test your new softener output.

Wanna find out what the black cloud is, that comes out with the hot water.
 

Reach4

Well-Known Member
Messages
38,796
Reaction score
4,412
Points
113
Location
IL
Gotcha. That could be a sulfur-iron compound or other sulfur item. It could be sediment. Ask your neighbors if they see such black clouds.

I would still flush your water heater. That can be pretty easy.
 

Melissa2007B

Member
Messages
369
Reaction score
9
Points
18
Location
Denver, CO
Gotcha. That could be a sulfur-iron compound or other sulfur item. It could be sediment. Ask your neighbors if they see such black clouds.

I would still flush your water heater. That can be pretty easy.

Problem is, where to flush it to? The crawl space is sealed - the vents and sidewalls, for energy savings. Down the tub?

There sound like only two possibilities for the cause. The higher water temps are eroding the tank bottom ( makes sense, as the first tank only lasted 6 years ) OR that flexible hose is being eroded by the hot water, but I checked on them and they appear to be rated for 180 degrees, and our water has never gone that high.
 

Reach4

Well-Known Member
Messages
38,796
Reaction score
4,412
Points
113
Location
IL
Floor drain? If your WH is not in the basement, you could run a hose out the back or front door.

Tub is probably too high.
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
One other thing to consider...unless the humidifier is very close to the WH, even feeding it with hot water, it may not get much hot water there. The thing uses a maximum of 0.5g/hour...that's barely a trickle, and is likely what is enabling the stacking effect in the WH. IF the flow was higher, there'd be enough turbulence to prevent that. It shouldn't be too hard to swap the inlet to cold water, and just see how it works. My guess is, you'll not notice any difference and save yourself lots of grief and money in the process.
 

Melissa2007B

Member
Messages
369
Reaction score
9
Points
18
Location
Denver, CO
One other thing to consider...unless the humidifier is very close to the WH, even feeding it with hot water, it may not get much hot water there. The thing uses a maximum of 0.5g/hour...that's barely a trickle, and is likely what is enabling the stacking effect in the WH. IF the flow was higher, there'd be enough turbulence to prevent that. It shouldn't be too hard to swap the inlet to cold water, and just see how it works. My guess is, you'll not notice any difference and save yourself lots of grief and money in the process.

I tried that a few years back and there was a big difference. And the energy guy who was out here again recently, said that his company carries Aprilaire and sells these, and that if you lower the water temp, it can also cause unhealthy bacterial growth.
 

Reach4

Well-Known Member
Messages
38,796
Reaction score
4,412
Points
113
Location
IL
Way far from any door. And the tub actually is higher than the floor, by a few inches.
You can put hoses in series. It can be useful to put the connections above a shallow pan/skillet to catch any light leak. You can also replace the hose gaskets with new soft ones.

It is the rim of the tub that matters. You may have a sunken tub, which would have a rim a few inches higher than the floor that would work. A shower would work better than most tubs, if the WH is on the same floor.

The point is that for a complete draining, you would need the highest part of the hose a little lower than the WH drain outlet, unless you involve a pump.

Flushing can be done different ways. The simplest is to
1. Turn off the water, and put the WH in vacation mode, if it has one. Otherwise off.
2. Open a hot water tap to pass air.
3. Drain the WH completely
4. Turn the water supply on fully for a few seconds, and turn off. You are trying to cause turbulence to the bottom of the tank.
5. Do steps 3 and 4 several times. If you have a way to monitor the drained water, you could judge by what you are getting out.
6. Turn the water and WH back on. Close the hot water tap once the air has been expelled and just water is coming out.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks