Water Heater Install Question

Page 2 of 2  
Craig Robison wrote: ...

That would depend on your local cost structure. I would guess that in some situations you would recover the investment cost quicker than you think. In others it might not be worth it.

You also need to consider the recovery rate. Not all water heaters can re-heat water at the same speed. A high recovery 40 may be enough if your current model does not have a high recovery rate. I would also add that having one 60 gallon heater will result in far less standby losses than two 40's.

--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
" Would going from 40 to 60 and then dropping the temp from 150 to 125

I did run some numbers. Assuming the incoming cold water is 50 degrees, mixing 150 with it 3:1 gives you the 125 temp. So, a 40 gallon tank of 150 water could be mixed with 13.3 gallons of 50 degree water to yield 53.3 gallons of 125 water.
So, going to the 60 gives you 60 gallons at 125, vs 53.3 by the mixing approach. The other factor to consider is the heat loss through the tank is also proportional to the temp difference. Assuming an ambient of 55 degrees, with water at 125, you have a delta of 70 deg. At 150, the delta is now 95, an increase of 36%. So, your gonna lose 35% more energy through the tank with the higher temp. I think these two together mean that unless there is some other issue, like space, the bigger tank is going to be the better solution.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Craig Robison wrote:

I got to thinking. Since the only time you seem to have a problem is when you have company from out of town, it may be better to have put the electric first so most of the time you can have it turned off and you will not use any electricity and will not have any standby losses (heat loss from the tank). Then when expecting company you can crank up the electric unit. You might even set it up to heat just a little to temper the water rather than heat it so the gas unit can do the real work.
--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
in series that wouldnt work although he could do it by adding some valves.
although I would leave the tank full of non moving water for a extended time.
the best thing he can do is monitor his electric bill if it spikes then try something else
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ooops meant to say dont leave tank full of non moving water for extended time, baceteria might grow and become a health hazard
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Not to mention, during long periods of inactivity, hydrogen sulfide gas can build up inside a water heater. If exposed to an open flame, this gas can cause an explosion.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sure it would work. Probably not worth the effort, but it would work, and would even bring the water up to attic temperature before going into the gas water heater.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@aol.com wrote:

????
In a series it should work as I explained it. Why not?

Not in a series. In a series water has to flow through both tanks. In parallel it can flow through just one.

--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The only time two water heaters should be piped in parallel, is when they have the same capacity and flow rate.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
With the electric tank LAST in series, only turning on the electric tank during periods of peak use will not work, since the water after being heated by the gas tank would cool and never be heated in the electric last tank. espically is they didnt use hot water for a couple days
if his electric bills spike he could add some valves, during normal use water would enter electric tank first, and not be heated, going to gas tank for heating. this way water wouldnt sit stagnant in the electric tank. //// during peak use he would reverse this by changing valve position to gas tank first and turning on electric tank. valves are cheap, with 2 tanks of differing ages I would altering valving to isolate one tank or the other, that way when one fails as it certinally will one day he moves some valves and has hot water from the remaining good tank till the bad one is replaced.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I certainly could do that. Or I thought I could just use a couple of valves to bypass the electric water heater all together and take the gas heated water straight into the house, but, I am concerned about what happens to a full tank of un-heated water sitting for days. I also thought about putting in a power-vented gas model in series ahead of my existing model. With it there is no pilot light so I could put a switch to kill the power to the heater, no power = no heating, but this idea became somewhat cost prohibitive and again I would have the problem of water sitting in a tank un-heated. Would you guys (gals?) mind giving me some feedback on my second post about the insulation blankets. I really appreciate all the ideas so far. I do think I will take the advice and raise the temp on the gas heater a bit in an effort to keep the electric one from running at all. Craig
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
No matter what you do, be sure to put a drain pan under each of these water heaters in your attic and pipe the drain down to someplace in the living space where you will see it right away. It's easier than having to replace half your ceiling.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
the more insulation the better! Just DONT block venting or burner access on the gas heater! or wiring access on the electric
if you can insulate hot water line between and leaving tanks, that will save a little, and save running water till it gets hot too. insulated lines are a save save save!!
They have premaid hot water tank insulating blankets. safe convenient and pretty cheap.
just for the record I wouldnt leave any tank sit with stagnant water hot or not for a extended time. if were on vacation for a week I make a habit of running water espically hot but both when we get home, its cheap and seems a good precaution...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I have seen those blankets cause condensation to remain on the water heater, thus rusting it out sooner than it should have.

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

I already took the liberty of insulating the pipes. To their credit, the original plumbing was insulated as well, I just had to add to it when I ran some extra lines to tie the water heaters together. I have seen these pre-made insulation blankets at Lowes for I believe $14. Lastly I don't think that leaving a tank of water sit is a good idea either, therefore I will just try to keep the use of the electric heater to a minimum. Thanks for the feedback...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There is a drip pan under each heater. Code requires 6 inches deep (which they are). The are both connected to a 1" PVC drain line which exits the attic and dumps the water outside the house should they leak.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That's good, but make sure you can see any water from a window you look out a lot. I've seen people run them into rain gutter and never know they were leaking until the water heater bursts. Then they say "I guess that's where all the water on my lawn was coming from."

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.