Changing to a 230 volt water heater

[thunderjet]

I have been thinking about changing my element to a 4000 watt, to get more recovery when plugged into 50 amp service. which for me would be most of the time.
My wiring is a short run dedicated 12 gauge wire, with a 120 hot leg thru a 12 volt relay.
If I add a 230 volt by 20 amp breaker keeping black wire on new breaker and adding 2nd power line to a 3 way switch putting original white wire on black screw feeding heater and add new neutral to 3 way switch.

This would supply 230 volt when plugged in to tower and by flipping switch go back to 120 when on gen or 30 volt plug. I know the 4000 becomes more like a 1000 on 120 power, but my shedding will be less when on reduced supply.
If 3 way is in wrong position ie 230 when on 120 element would see same pole 120 on both legs and I would get no hot water until switched over to 120 setting.

If you can follow my ramblings does this make sense. or unsafe for some reason I am missing.

TJ

[mel s]

Originally Posted by thunderjet

I have been thinking about changing my element to a 4000 watt, to get more recovery when plugged into 50 amp service. which for me would be most of the time.
My wiring is a short run dedicated 12 gauge wire, with a 120 hot leg thru a 12 volt relay.
If I add a 230 volt by 20 amp breaker keeping black wire on new breaker and adding 2nd power line to a 3 way switch putting original white wire on black screw feeding heater and add new neutral to 3 way switch.

This would supply 230 volt when plugged in to tower and by flipping switch go back to 120 when on gen or 30 volt plug. I know the 4000 becomes more like a 1000 on 120 power, but my shedding will be less when on reduced supply.
If 3 way is in wrong position ie 230 when on 120 element would see same pole 120 on both legs and I would get no hot water until switched over to 120 setting.

If you can follow my ramblings does this make sense. or unsafe for some reason I am missing.

TJ

TJ
Why do you need a 240 volt water heater?
Seems like a lot of work for no good reason.
Mel
'96 Safari

[Waiter21]

What size water heater do you have? ( I'm envisioning a 6 gallon as I write this)

Have you considered a tankless water heater.

I'm a servo control guy. You would be adding a very hi capability to swiing the temperature but the controls are not designed to handle that fast of a temperature swing. I would predict a lot of pulsing of the heaters (on/off/on/off) and a lot of overshooting of the temperature setting.

Tankless heaters do what your thinking about but have flow sensors able to adjust the heating element based on flow thru the line, They can provide consistent temperature from zero to full flow.

Just my thoughts and ramblings....

[thunderjet]

As I am very cheap I am not changing the water heater just adding new element, breaker and 3 way switch about 40 dollars. My math tells me my 10 gal 1500 watt heater from start up takes 1 hour and a 4000 watt takes about 24 minutes. On a reheat from t stat make that 20 minutes down to 8 minutes. And I think t stat cycling would not be overshooting temp any more than normal element.

Thanks for all input

I have had this rv for all of its 10 years and do all of the service.
I was more worried about future owners or service techs.

[Old Scout]

Careful--alot of campgrounds dont have true 240v [phased] hook-ups--not sure what that does to neutral lines, load lines, etc. My older RV water heater is a propane/ electric combined unit--turning on the propane side during heavy hot water use does a much better job than the electric only side--just a thought.....
PS-- most electrical codes dont allow for a manual process to keep users from potentially mixing 240 vs 120volt sources--with good reason.

[ChasA]

Thunderjet,
What problem are you trying to solve. Our 10 gallon water heater provides all the hot water the wife and I need. If we are taking showers one right after the other, we run both the electric and propane. As for the initial heat up cycle, the motor aid feature provides abundant hot water while traveling and it stays hot for quite awhile after arriving at our destination.

[dennis45]

Sounds like a whole bucket to me

[Sky_Boss]

Originally Posted by Waiter21

...
Have you considered a tankless water heater.

...I would predict a lot of pulsing of the heaters (on/off/on/off) and a lot of overshooting of the temperature setting.

Tankless heaters do what your thinking about but have flow sensors able to adjust the heating element based on flow thru the line, They can provide consistent temperature from zero to full flow.

...

Tankless systems can be a good answer but...don't you hate that?

They can also be picky about water flow rates. In particular shower flow rate restrictors can cause flow rate sensors to shut down the WH and cause "slugging". That is when you get slugged by a bunch of cold water because the WH doesn't see a demand due to a hot water flow rate.

The scenario most common is that you have a very restrictive shower head and don't want a hot shower further reducing water flow through the WH. Suddenly you get slugged with all cold water because of a slight drop in water pressure either from cold water being used in another part of the RV or neighbors in the CG.

The good news is that you shouldn't ever get scalded because the mixer valve should keep that from happening when the WH puts out heated water again. The bad news is that a slug of cold water can fool you initially into thinking you were scalded and scare the heck out of you.

Tankless users, especially in RVs, need to be very aware of this. HOWEVER...I haven't seen users of hydro heating systems talk about this much. Perhaps RV tankless systems are more adapt in dealing with low hot water flow rates.

Rambling done.

[WSRG]

I do the same as ChasA. You said you want a faster recovery from your water heater. Just turn on the propane WITH the electric. Fast recovery...No Muss, No Fuss.


Bill

[Sky_Boss]

Originally Posted by WSRG

I do the same as ChasA. You said you want a faster recovery from your water heater. Just turn on the propane WITH the electric. Fast recovery...No Muss, No Fuss

BTW...

[dennis45]

Or, if you're really cheap, just get a 45 gal drum, paint it black and mount it on the roof with a hose to your shower. Lots of hot water for FREE!

[stik]

Originally Posted by thunderjet

I have been thinking about changing my element to a 4000 watt, to get more recovery when plugged into 50 amp service. which for me would be most of the time.
My wiring is a short run dedicated 12 gauge wire, with a 120 hot leg thru a 12 volt relay.
If I add a 230 volt by 20 amp breaker keeping black wire on new breaker and adding 2nd power line to a 3 way switch putting original white wire on black screw feeding heater and add new neutral to 3 way switch.

This would supply 230 volt when plugged in to tower and by flipping switch go back to 120 when on gen or 30 volt plug. I know the 4000 becomes more like a 1000 on 120 power, but my shedding will be less when on reduced supply.
If 3 way is in wrong position ie 230 when on 120 element would see same pole 120 on both legs and I would get no hot water until switched over to 120 setting.

If you can follow my ramblings does this make sense. or unsafe for some reason I am missing.

TJ

I think we need to hear from a REAL electrical guy: Engineer, certified electrician, someone that has more than a casual knowledge of electric feed systems.

No where in ThunderJet's narrative do I see ANY mention and/or consideration of ground and/or neutral in his rather unorthordox scheme. This leans me toward a feeling that this rather odd method to remedy a non-existent(?) problem could cause problems with the power distribution in an RV Park, not to mention possible problems/damage to his RV. JMHO

I also concur with the gas plus electric mode for faster initial heat and faster recovery times in general. Also, an hour to bring a 10 gallon tank upto temperature sounds rather long. What if is is just a faulty/old heating element. Does his tank require an anode, and if so, does THAT have anything to do with recovery times. I'm clueless on the anode tanks, as mine doesn't have one.

[Waiter21]

What the heck, give it a shot, let us know what happens.. :-)

[autofish]

Thunderjet a lot of home spas us a 1000w-4000w 120v-240v heater and can be switch for 120v or 240v so as long as the rv is wire correctly this will work fine.