2 electric water heaters together

[radstorm]

Not sure of this going to plumbing or here, but anyways I want to put 2 electric water heaters in, both are 30 gal, 230V. My question is due to my service only being 100 AMP can I just run the bottom element on both and dc the top one. If so do I still leave both t-stats connected? The point being cutting both back on amp usage. 2 would draw 60 amp if they both fire up. I realize also this means the water will take longer to heat up, but I'm a patient guy. I am not rich so I can't write Bob Vila a blank check or pay thousands to an electrician for an upgrade. Thanks

[HayZee518]

are you stipulating ac and dc usage?

[thedcdude]

I think by "DC" he means disconnect???

[pushkins]

Why not install one 50 gallon tank ????? then you don't need to disconnect any elements.
Disconnecting one element in each tank will obviously take longer to heat or recover heat after use, therefore increase costs etc...

[radstorm]

Yes I meant disconnect, sorry bout that. pushkins as I said, not a rich guy. I priced a 50 gallon one, and well being on a pension. I would have to give up eating to afford it..LOL The thing is I already have these (2) 30 gallon heaters, one is in use the other is just sitting around. I could just get by still on the one, but I get a little tired of the GI shower routine

[HayZee518]

check out my illustrations. you'll have to rewire the upper element. go to illustrations and find water heater wiring.

[paul52446m]

Not sure of this going to plumbing or here, but anyways I want to put 2 electric water heaters in, both are 30 gal, 230V. My question is due to my service only being 100 AMP can I just run the bottom element on both and dc the top one. If so do I still leave both t-stats connected? The point being cutting both back on amp usage. 2 would draw 60 amp if they both fire up. I realize also this means the water will take longer to heat up, but I'm a patient guy. I am not rich so I can't write Bob Vila a blank check or pay thousands to an electrician for an upgrade. Thanks

Are you going to draw water off both heaters at the same time? Are you going to run both lower element at the same time? Paul

[radstorm]

HayZee, I don't see any illustrations. How do I access them?

Paul, well that's another thing..I am not sure which route to take. I checked around and it seems there is a lot of argument about rather to go series or parallel. I just want to have the hot water last longer during showers, etc. However the reason I just want to use one element on each is to lower the amp draw on my service box. I guess if only one element per heater combined that would be 30 amp again. Using both of course and them both coming on to recover at the same time would take it up to 60. With only 100 amp service that would be sucking a lot of my total load capacity

[HayZee518]

go to the FORUMS in the taskbar, look for ILLUSTRATIONS. Find the post that says WATER HEATER DIAGRAMS. Here you'll find a diagram of how to wired water heaters along with the color coding. As far as water heaters go, there's a dip tube that comes off the cold water supply and feeds cold water to the bottom of the tank. Initially, the upper element comes on first to heat the water, then it swaps to the lower element. The hot water stratifies to the top of the tank where its needed FIRST. Then as you use it, the lower element's thermostat kicks in when it senses a lower temperature from incoming water. If I were you I'd pipe the two tanks in parallel. You'd be drawing water from both at once. Yes, you'd install another two pole breaker, but being 30 gal heaters would draw less than 20. I got a 42 gallon that is fed by a two pole 20.

[paul52446m]

HayZee, I don't see any illustrations. How do I access them?

Paul, well that's another thing..I am not sure which route to take. I checked around and it seems there is a lot of argument about rather to go series or parallel. I just want to have the hot water last longer during showers, etc. However the reason I just want to use one element on each is to lower the amp draw on my service box. I guess if only one element per heater combined that would be 30 amp again. Using both of course and them both coming on to recover at the same time would take it up to 60. With only 100 amp service that would be sucking a lot of my total load capacity

If you are going to pipe them up in parallel, and thats the way i would do it,
It is very important to have the piping 100 percent equal on both cold and hot piping or you will not get equal draw off the heaters. This will be the only way you will get a lot more hot water. If you do it right it will work.
Like HayZee518 told you only one element at a time comes on in a water heater so why can't you leave both upper and lower elements wired up, you would still never have more than two elements at one time coming on. Paul

[radstorm]

Thanks, HayZee, got it now

Paul, then I have to ask why my water heater requires 10 awg, and a 30 amp breaker. Is this because of the way it is wired now? But yes, parallel does make more sense to do

[paul52446m]

Thanks, HayZee, got it now

Paul, then I have to ask why my water heater requires 10 awg, and a 30 amp breaker. Is this because of the way it is wired now? But yes, parallel does make more sense to do

I am not sure what elements you have in it now. Have you checked to see how many amps it is drawing, and size you elements are. I know on some heaters you can put different elements in them. But if it calls for No 10 wire, then you would need a 30 amp breaker to run it. You are only suppose to use up to 80% of a breaker, so that means a 30 amp is needed to run 24 amps. Paul

[HayZee518]

the formula to use is watts divided by voltage to get amps and / or volts times amps to get watts. a water heater with two 4500 watt elements draws 18.75 amps and like I said before only one set per heater will be on.

[radstorm]

Yes Paul, that was a good point. I checked and they are 4500 watt which as HayZee said would actually be drawing 18.7 amps. Why it calls then for 30 amp is beyond me. Unless they do in this setup both run. But then in that case it would exceed 30 amps.

Then again another factor might be the upper one is less wattage (I only checked the bottom one) or something. But if you look at most water heaters here in the US i/e whirlpool, american, ao smith, etc, they pretty much all go by that 30 amp guideline. Well they make lesser wattage ones, so looks to me that I will just downgrade them I have seen some as low as 1500 watts.

This is a good point also now that I think back to when I worked apartment maintenance. I saw a lot of water heaters fry inside, but still not trip the breaker..hmm

[paul52446m]

Yes Paul, that was a good point. I checked and they are 4500 watt which as HayZee said would actually be drawing 18.7 amps. Why it calls then for 30 amp is beyond me. Unless they do in this setup both run. But then in that case it would exceed 30 amps.

Then again another factor might be the upper one is less wattage (I only checked the bottom one) or something. But if you look at most water heaters here in the US i/e whirlpool, american, ao smith, etc, they pretty much all go by that 30 amp guideline. Well they make lesser wattage ones, so looks to me that I will just downgrade them I have seen some as low as 1500 watts.

This is a good point also now that I think back to when I worked apartment maintenance. I saw a lot of water heaters fry inside, but still not trip the breaker..hmm

You did not read my post. I said you can only use 80 percent of a breaker. So a 20 amp breaker is good to run 16 amps, and since you are running 18 plus amps, that is why they go to 30 amp breaker and no. 10 wire. So if both lower elements are going at once you would be using about 37 amps. Paul