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.
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
ooops meant to say dont leave tank full of non moving water for extended time, baceteria might grow and become a health hazard
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.
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.
????
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.
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.
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
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.
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...
I have seen those blankets cause condensation to remain on the water heater, thus rusting it out sooner than it should have.
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.
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...
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."
:>> Craig :>>
:>>
:> Hi, :> I always had two gas heater in series. But have no experience with :> gas-electric combo. I'd think they'll have different recovery rate. :> Tony : :I agree, I suspect that the 3800 watt, single element, el-cheapo electric :water heater recovers pretty slow. Compared to the 30K BTU NG heater... :another reason I put them in series. :Craig : What I don't understand is setting them at the same temperature. If you are going to do that I'd think you'd have the gas one before the electric one and set the electric one's thermostat a little higher than the gas. Then the gas one will do most of the work (which is what you want). IOW, if you want 125 degree water, set the gas one to 110 or 115 and the electric to 125.
Dan
"> :>>
Well, I've been down this road too. In fact for a while I ran the gas heater (which is the first in the series) at about 115 degrees and the electric at 120. My thinking was that the gas one would do "most" of the heating and the electric could kick it up that last 5 degrees. In this manner the standby heat loss from the gas heater would be as low as possible because the water is only at about 115. The new heater I suspect has the better insulation and so I would be wasting less energy keeping it at 120. But, now I'm not so sure... perhaps it is better to run the gas heater at say 130 and in so doing try to prevent the electric one from even turning on under normal loads and only run during times of heavy demand. But that would increase my standby loss in the gas heater which means it starts costing more. The question is, (taking into consideration the standby losses from both water heaters) is it cheaper to run the gas at 115 and let the electric one raise it to 120 OR is it cheaper to run the gas at 125-130 and try to prevent the electric one from running at all? I realize that they both will run from time to time as a result of the standby losses... While I'm thinking about it, is there a way for me to track how much the electric heater runs? I need like a 240 volt clock that I can hook to the terminals on the heating element or perhaps some sort of inline meter (much like the utility company uses). I figure with something like that I can just "tweak" my settings from weak to weak until I find a combination that runs the electric heater as seldom as possible.
Craig
HomeOwnersHub website 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.