Dual water heaters - can I disable one?

Page 2 of 3  
On Monday, June 9, 2014 9:39:18 AM UTC-4, trader_4 wrote:

plus as a example for a momentlets take this to a extreme....
how much electric would it take to keep the water hot in a vacuumn bottle.???
amost none. so insulation might help a lot, saving most of the energy you want to save by turning one water heater off, while still having the capacity
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, June 9, 2014 9:52:44 AM UTC-4, bob haller wrote:

Another way of looking at it, compare it to an attic. In winter, the attic could be 20F, while the heated air below is 70F. That's a 50F temp delta and the sound science says having 12" of insulation makes a substantial difference versus 4" of insulation. With a WH set at 130F, sitting in a basement that's 55F, you have an 75F temp delta, 50% higher than the attic example. That means you're going to have a roughly 50% greater driving force to move heat out of the tank. IDK how much insulation is in a WH, but I doubt it's even 4" thick. And IDK how much difference it would actually make, but I woulnd't be surprised for it to have a reasonable payback and for it to be worthwhile.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

plus water heater insulation blankets are cheap.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 6/10/2014 9:02 AM, trader_4 wrote:

I'm thinking he should replace the 50 gallon water heater with a series of vacuum bottles wrapped in 4" of insulation.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Based on what follows, I'm sure he meant to say parallel.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sorry for the delay. You've probably moved on by now, but for the record these heaters are from:
State Industries Model # ES652S0RT0W 240 VAC, Single Phase Upper Watts: 0 Lower Watts: 5500 Total Watts: 5500 Capacity: 50 gallon
So now, 6 months after closing the inlet valve on one heater and unplugging it from its receptacle, all has been well. We've had guests stay with us on multiple occasions and there have been no issues with running out of hot water. I would have to say that a single 50-gal heater seems to be perfectly sufficient for our needs. I do plan to switch over to the disabled heater at some point, possibly on a yearly basis.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/1/2014 4:02 PM, Jim Joyce wrote: [snip]

Are the heaters in parallel? Sounds like it if you can shut off the inlet on either one and still have water flowing.
I'm thinking that if I were in your shoes and decided to keep both in the system and yet only use one at any given time, I would plumb them in series with a reversible bypass of some sort. Maybe I can clarify a bit with a verbal diagram.
In position "1" Water heater "A" is turned off (electrically) and water from the main (or water softener) flows into it (making it an old fashioned tempering tank) and then flows on to Water heater "B" which is active electrically and actually heats the water.
When you "switch over" annually or semi-annually, their functions are are reversed and "B" becomes the tempering tank and "A" is the water heater.
With the arrangement that you are apparently using - a parallel setup allowing for one heater to be completely shut down from both the electrical system and the plumbing system, I'd be a bit concerned about bacterial growth, etc. in the "off line" heater.
Does that make sense?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
However you arrange valves to go down to one heater, I would definitely switch between them at least every six months, and probably drain the unused one as soon as it was off-line to get the sludge out of the bottom before it really congeals.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 01 Dec 2014 22:16:49 -0600, Unquestionably Confused

Yes, they are in parallel.

I see what you're saying, but is bacterial growth a valid concern? The doomsday prepper crowd has convinced me that bacterial growth isn't really an issue when water is stored in the dark, as it would be here. I was thinking a simple flush would be all I need to do when I switch over.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/2/2014 12:53 AM, Jim Joyce wrote:

[snip]

I honestly don't know if it would be a problem or not. I could ask my daughter the biochemistry professor to get the answer for sure<g> BUT we know that there's both aerobic and anaerobic bacteria and I'm not sure that absence of light is going to mean much. Take a 8 oz bar if Philly cream cheese, spit on it, place it in a sealed, black plastic Tupperware container and put it in your t-shirt drawer for a month and report back on your findings when you open it.<g>
Given that in my example of moving your system to a tempering tank arrangement, I think that the question becomes moot. Same thing with the sediment issue perhaps. Clearly it would obviate the need to flush the water heater and lines when switching over.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 1 Dec 2014 20:39:09 -0800 (PST), " snipped-for-privacy@sbcglobal.net"
I can't drain the unused heater because its outlet pipe is connected to the outlet pipe of the other heater. Each heater has a valve on its respective inlet pipe, but no valve on the outlet pipes, so if I open the drain valve on either heater, the other heater will simply (try to) reverse fill it again.
Besides, "sludge" and "congeal" don't really describe the hard water sediment, do they? Without actually having water flow through, and without the heating cycle, I wasn't expecting new sediment to be an issue.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, December 2, 2014 1:56:35 AM UTC-5, Jim Joyce wrote:

It would not refill, you could drain it, if you just shut off the incoming cold water. But I agree, I'm not sure that I'd worry about draining it because of worrying about bacteria growth. Especially if you're not using the hot water for drinking, and/or as you suggested, flush it for awhile when returning it to service.
I have some experience with a similar situation here. A friend has a house with two tanks, gas, shut one down like you did, left it full of water. Only negative was after not using it for a few years, went to put it back in service before Hurricane Sandy. It would not fire. Upon inspection, there was some rust debris visible that had fallen down into the pilot light area. Probably just needed a vacuuming to solve that, but IDK for sure what was later done to it. With electric, you don't have that issue.

I agree.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

They are interlocked by the top thermostat so they only come on one at a time. The top one starts the process by energizing the top element and when the top thermostat is satisfied, it switches to the bottom element and that thermostat. If the bottom element went bad, the only indication would be you ran out of hot water sooner than normal. If the top one goes bad, you don't get any hot water because you never satisfy the top thermostat.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/2/2014 1:06 AM, snipped-for-privacy@aol.com wrote:

Read the OP's specs again. There is no upper element and, therefore, there is no upper thermostat.
I am not sure your statement is entirely correct if the electric water heater is dual element (as most are). Isn't the so-called "quick recovery" mode/feature a function of both elements heating the water simultaneously when demand is great?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, December 2, 2014 8:11:00 AM UTC-5, Unquestionably Confused wrote:

I don't think both are on at the same time with the typical residential WH. The ones I've seen, work as gfre described. They are rated at say 4500W and have two elements that size. Only one comes on at a time. That reduces the circuit ampacity required. As temp goes down, the bottom comes on first. If the upper level water gets cool enough, then it switches the bottom off and the top on, to provide more heating to the water that is going to be drawn first.
Why the OP's WH only has a bottom element, IDK. That isn't typical and seems dumb.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/2/2014 8:05 AM, trader_4 wrote:

[snip]

Looks as if you're correct from the limited "research" Google and I just did<g> The upper element is "responsible" for heating about 1/4 of the tank's capacity and provides the quick recovery

Agreed, single element would make sense in a small, point of use heater (like in a workshop restroom, etc) but with 50 gallons, I sure wouldn't want one.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 02 Dec 2014 07:10:58 -0600, Unquestionably Confused

The only thing "quicker" about the quick recovery is the top element is only heating the water at the top. You only have one on at a time. These are on a 30a breaker and one 5500w element draws over 22 amps by itself
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 02 Dec 2014 02:06:53 -0500, snipped-for-privacy@aol.com wrote:

Thanks, but that's completely wrong in this case.
Each water heater is completely standalone. Within each heater unit, there is a bottom thermostat connected to a bottom heating element. Where the upper thermostat would be, there are mounting holes but no thermostat. Likewise, where the upper heating element would be, there is only a dummy plug.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 02 Dec 2014 08:21:50 -0600, Unquestionably Confused

It's not as if I selected it myself. <g> The home builder decided that twin 50-gal heaters would be nice, and he apparently selected this model that has a single element. Perhaps he bought in quantity and got a deal.
If I really had to, I could make this a 5 bedroom house, meaning there could potentially be what, about 10 people living here in 3000 square feet, sharing 3 bathrooms? Fully populated like that, maybe dual 50-gal heaters make sense, but there are only two of us here, not counting occasional guests, so a total of 100 gallons of hot water seems excessive.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I agree with everything you said, except that it would really try to refill from the other heater. The only way to drain one and keep it drained is to shut off the water to both heater units.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.