Hot water heater issue

DownTheAvenue wrote:

You are drawing more than 30 amps with all of that running by adding the water heater.

1400 watt water heater element at 120 volts = 11.66 amps
A/C running with low blower 1250 watts at 120 volts = 10.41 amps
Dorm refrigerator 375 watts at 120 volts = 3.125
RV refrigerator 960 watts at 120 volts = 8 amps
Converter 875 watts at 120 volts = 7.29 amps

TOTAL LOAD 40.485 AMPS

Now you know why the 30 amp breaker tripped
Without the water heater you were just under the 30 amp threshold, so when you added a big load like the water heater, you overloaded the 30 amp circuit and the main breaker did what it was designed to do.

Clearly there is too much current since the breaker is popping, but some of these numbers are way off.

A typical dorm fridge is, I think, somewhere around 100W running (but a lot more when the compressor is starting up).

An RV fridge is around 300W, not 960W.

The converter's power consumption is variable depending on the 12V load it's seeing. 7A or so is not unrealistic, particularly if the house batteries are low and being recharged. (Many converters have rather poor power factors, as well, which does not do the current consumption any favors.)

Since things seem to be working better with the replacement water heater element, maybe the old element was partly shorted and consuming somewhat more current that it should have been. It's not a common failure mode, but not beyond the realm of possibility.

DownTheAvenue wrote:

thekevin wrote:
I have only owned a camper for 6 days and I have already learned a lot. So basically if I am not willing to sacrifice the AC or the fridge I need to run the hot water heater on propane.

EXACTLY!

And run fridge on propane to lighten AC Power Demand a bit more.

We have a 50A 5th wheel.
Whenever we used a 30A or lower power source water heater and fridge got swapped to propane. That way I didn't have to 'manage' the AC Demand.

JimK-NY wrote:
I have an Atwood 6 gallon heater. There is a thermostat but it is not adjustable and must be preset at close to boiling. Actually I believe I read the temperature is set at about 180 degrees. That is way too hot as far as I am concerned.

FYI.....
1) Atwood uses a 140*F 'normal' t-stat----control heating cycles
2) Atwood uses a 180*F ECO t-stat (Energy Cut Off)----Hi temp backup to normal t-stat. When it opens it shutdown all DC and triggers the Fault Light (Red light at on/off panel)
3) Atwood uses a 190*F Thermal Fuse (One shot device)---opens if burner blow back occurs from combustion chamber/burner tube (inside clear tubing connected to t-stat terminal) Shuts down ALL DC until Replaced
4) Atwood uses a T&P Relief Valve ----opens at 210*F/150 PSI


Atwood does market an adjustable t-stat----110*F to 150*F
Part # 93105
Atwood does market an optional 130*F t-stat
Part # 91470

thekevin wrote:
I have only owned a camper for 6 days and I have already learned a lot. So basically if I am not willing to sacrifice the AC or the fridge I need to run the hot water heater on propane.

EXACTLY!

I have only owned a camper for 6 days and I have already learned a lot. So basically if I am not willing to sacrifice the AC or the fridge I need to run the hot water heater on propane.

Since we are basically living in our trailer at home (driveway full timing), I've been keeping the water heater on gas (6 gallon), and the cover on the inside of the camper is currently removed, since I have not put it back on after un-winterizing. With the cover off, I can hear the gas burner kick on and off, and we're inside the camper a lot! It seems to kick on after running hot water from any faucet, but only very, very rarely do I hear it kick on any other time. It uses very little propane. If the water heater is the only thing using gas, and you never ran any hot water from the faucets and you just let ambient temperature cool the water heater, and let it heat naturally that way.... a 30 pound propane tank would keep the water hot for probably 8 months.

How much propane gets used, depends upon how much water you use and the ambient temperature around the water heater. Of course, the colder it is outside, the harder the water heater has to work. And the colder the water is coming IN TO the tank, means the water heater has to work harder to raise the temperature. It takes more propane to heat 40 degree temperature water to 130 degrees, than it does if the water is already starting out at 80 degrees when entering the tank. So, really, there are a lot of variables which will determine how much propane actually gets used.

Old-Biscuit wrote:
Depends ......

.....As for how much propane.
...
Atwood uses ... a 10,000 btu rated burner
.......

1 gallon of propane-----91,000 btu

I use my heater about 20 minutes a day. That would be about 3000 BTU per day. Or about 30 days per gallon or 140 days per tank. That sounds about right. I use a lot more propane for cooking and still typically get about 2 months of use from a tank of propane. (I have a compressor refrigerator and rarely use the space heater for more than a few minutes.)

thekevin wrote:
I was running the AC, fridge, most of the lights in the camper, a dorm fridge out front, and then turned on the water heater. I did try unplugging the dorm fridge and see if that did it but it still flipped it. I figure AC, fridge, water heater would all be running at the same time fairly often.

You are drawing more than 30 amps with all of that running by adding the water heater.

1400 watt water heater element at 120 volts = 11.66 amps
A/C running with low blower 1250 watts at 120 volts = 10.41 amps
Dorm refrigerator 375 watts at 120 volts = 3.125
RV refrigerator 960 watts at 120 volts = 8 amps
Converter 875 watts at 120 volts = 7.29 amps

TOTAL LOAD 40.485 AMPS

Now you know why the 30 amp breaker tripped
Without the water heater you were just under the 30 amp threshold, so when you added a big load like the water heater, you overloaded the 30 amp circuit and the main breaker did what it was designed to do.

I have an Atwood 6 gallon heater. There is a thermostat but it is not adjustable and must be preset at close to boiling. Actually I believe I read the temperature is set at about 180 degrees. That is way too hot as far as I am concerned. I suppose I could look for an adjustable thermostat but instead I just time the heating. I have a cheap timer that I velcrod on to the kitchen stove vent. If I have recently filled the tank with cold water, the water heater needs to run about 20 minutes. For water that is a room temp, I need about 16 minutes. I try to heat the water so I get a hot comfortable shower without using any cold water. Since I only use about 1 gallon for a shower and my tank holds 6, the temperature remains pretty constant for the whole shower. My wife uses about 2 gallons and I turn the heater to back on while she runs the shower and again the water temperature stays pretty constant.

I don't bother with hot water for washing dishes. I have a plastic basin that I partially fill with warm water heated on the stove. That helps keep the water use down and it only takes a minute or two to heat the roughly 1 quart of water I need. Endless running hot water is great at home but just not worth it when living in an RV. That is partly a compromise I make since I rarely stay in places with hook ups.

Depends ......

Propane has t-stat for temp control as does electric element.
When temp is reached t-stat shuts down heating. When temp cools down t-stats closes and starts heating cycle again.

You can leave electric on....or turn on 30 minutes prior
You can leave propane on....or turn on 20 minutes prior
You can leave them BOTH on----or turn on 10-15 minutes prior

As for how much propane.
Depends on which water heater brand and size you have
Atwood uses a 8,000 btu and a 10,000 btu rated burner
Suburban uses a 12,000 btu rated burner

1 gallon of propane-----91,000 btu