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 > How to tell when water heater is at max?

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Posted: 02/08/21 09:57am Link  |  Quote  |  Print  |  Notify Moderator

wopachop wrote:

I turn my water pressure down too. Just enough to make it come out.

Does anyone have a rough guess of how much propane is used to heat up the tank? There are times, like this morning, where i forgot to turn my electric element on. Wanted to flip the propane on too to hurry up the process but also hate having to go refill propane.

Not a tremendous amount of propane. Burning propane produces 91,500 BTU per gallon of propane (or 21,591 BTU per pound). Do some division with the BTU rating of the burner in the water heater to get the propane consumption per hour; the burner's BTU rating is technically a BTU per hour rating. If it's 12,000 BTU (which is the rating for the first 6 gallon RV water heater I found data on), twenty minutes of burn time would use about 3 ounces (by weight) of propane, or 1/22 of a gallon.


Southern California

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Posted: 02/08/21 09:58am Link  |  Quote  |  Print  |  Notify Moderator

Ammeter would tell you when the electric element is on/off. If you had an EMS with display you might already have an ammeter.

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South Louisiana

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Posted: 02/08/21 11:22am Link  |  Quote  |  Print  |  Notify Moderator

The prize goes to Valhalla. Get a killawatt or something to tell you how many watts you are pulling. When it drops about 1800 watts then the filament stopped heating.


No paticular place.

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Posted: 02/08/21 11:23am Link  |  Quote  |  Print  |  Notify Moderator

wopachop wrote:

Correct cold water is replacing the hot water. But it does not seem to mix. Someone has posted a picture of the water heater insides. It has baffles that i believe are designed to keep the cold water from mixing with the hot.

Which goes alone with how the shower feels. Temp is normal. I feel it get colder and i turn the water handle to full hot. That lasts about 5 seconds and everything that comes out from there is cold water.

Yes, they try to minimize it by adding and drawing water from different strata...and if you are doing 0.5gal showers, it will work pretty well.

If you are using 3-5gal, there will be enough mixing to make for a noticeable temperature drop.

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Harrisburg, PA

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Posted: 02/08/21 12:39pm Link  |  Quote  |  Print  |  Notify Moderator

I've never worried about it. When I get water and electric hooked up I turn on the water heater. Not very often I am taking a shower in the first hour after arrival. From there on the water is always as hot as it is going to get.
There are some that refuse to let their water heater on all the time. I can understand that if you are using a generator or paying for the propane. But when hooked up to campground electric. Leave it on.

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Regina, SK, Canada

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Posted: 02/08/21 12:48pm Link  |  Quote  |  Print  |  Notify Moderator


Stock water heater rods for RV's are 1400 watts. On my ten gallon unit, starting with water at the ambient temperature (66 f) it takes 90 minutes to the first cycle.

On propane that drops to about 30 minutes. If I use both electric and gas it takes about 20 minutes.

If I leave it on electric, the tank will cycle about every four hours and runs for about 15 minutes.

Since I pay for propane, and don't for electricity guess which one I use?

I find that turning it on first thing in the morning and having my breakfast--that there is enough warm water for a shower--and enough for dishwashing the rest of the day.

Regards, Don
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Posted: 02/08/21 12:49pm Link  |  Quote  |  Print  |  Notify Moderator

schlep1967 wrote:

. But when hooked up to campground electric. Leave it on.
Probably the best idea, but there's that situation where someone else has just showered or you've just done the dishes.


San Diego Ca

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Posted: 02/08/21 02:06pm Link  |  Quote  |  Print  |  Notify Moderator

The lowest budget check I can think is to turn on the electric until you think it might be done. Then turn on the propane. If the water heater lights, it wasn't done heating. So turn off the propane and wait another 10-15 minutes and try again.

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Posted: 02/08/21 02:35pm Link  |  Quote  |  Print  |  Notify Moderator

Old-Biscuit wrote:

AquaHot, HydroHot, Oasis ------not the typical tank RV Water Heater

Attwood 1400W element
4779 BTU

Suburban 1440W element
4915 BTU

Gas 9000 BTU input, assuming say 60% efficiency 5400 BTU, most likely efficiency is closer to 70%-80% or about 6300 BTU-7200 BTU..

So, unless you have flunked math, gas IS faster, gas has a much quicker recovery and gas will sustain a longer draw..

And for the record, I ALSO HAD a Suburban 6gallon gas only, at one time, only took 10-15 minutes till it had scalding hot water..

RV water heaters unlike a sticks and bricks are typically set to 130-140 F temps, which is way above scalding point, it is intentional that they are set to high temps.. It allows you to heat a smaller amount of water bet yet draw for longer time.. Basically you will mix 1 part hot to 4 parts to cold to get a hot shower..

So if you use 1 gallon of water per minute and shower for 10 minutes you will have used 2 gallons of hot and 8 gallons of cold in that time frame.

Even if you used 1 to 1 that means a 6 gallon tank will get you a 6 minute shower..

Now if you DROP the amount of water used, you can now extend your time..

.5 gallon of water used per minute now means your shower can last 12 minutes even at a 1 to 1 mix..

I have personally never ever used anywhere near 1 to 1, basically slightly opening the hot water till it trickles then adding in much more cold water until I get a spray.. I am sure I am mixing 1 to 4 or 1 to 5.. And HAVE had no issues getting a darn hot 15 minute shower with hot water to spare..

Folks don't seem to understand that you cannot treat a RV like a sticks and bricks.. A sticks and bricks has a 40-50 gallon water heater..


Davison Michigan (East of Flint)

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Posted: 02/08/21 03:58pm Link  |  Quote  |  Print  |  Notify Moderator

There is a very easy And I mean EASY (And safe) way to do it... IN fact a couple of them.. one I have lying in the next room (it is not YET for sale.. that happens much later and not on line)

The two are SURGE GUARD made by Southwire (Formerly TRC)
and the Progressive Industries EMS
We call these Surge Protectors but the top end units are so much more.

1: Like the elcheapo outlet strip "Surge Guards" they supress spikes...
2: They monitor voltage and if it goes too low (or high) they turn you off (See note)
3: they monitor current. (They just report it they don't consider it)

Note: Many are the RVers who plugged into a 30 amp outlet and found it fed with 240 volt instead of 120.. The top end units absolutly protect you if you do this (Lower priced units will not). (Lower priced units also do not monitor current)

So how does this help with the water heater?

With the WH off note the current amps) on a 50 amp note both legs
Now turn on the WH and note the *INCREASE* or agout 12-13 amps (on a 50 amp rig this will be in one leg.

When the increase goes away.. Water heater cut off

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