Mystery of water heater

K Kumar · 03-03-2018, 06:20 PM

Hi,

I am having an unusual situation.

My water heater (Suburban) was working well on propane until a few months ago. It started shutting off, partly because propane tank would become empty. I would change the tank, hit the switch (under the sink) & it would come on again. A couple of times, I had to reset the thermostat on the outside.

Now, propane has stopped working completely. I have replaced both the thermostats outside, but propane burner does not light up. Tried the 110 V switch and it tripped the circuit breaker. Think the heating element may have shorted out. So, I just turned of the circuit breaker inside the trailer for the hot water and decided to live without hot water.

The next day, I notice I have warm water. It is not boiling hot, but warm.

I was puzzled and started looking into the manual. Manual indicates heater can operate on 12V DC, gas & 110V AC. So, I am thinking that this water heater is operating on 12V DC. Manual shows DC circuit for heater having a switch, but I am unable to locate it.

I called Trailmanor & explained the situation to them, thinking they would be able to give me some pointers on the phone. Unfortunately, the guy seems to be new on the job. He looked into the manual, didn't seem all that familiar with the circuit and said he would have to get back to me.

I would appreciate if some of the experts on this forum can give me some pointers on my unusual situation. I think my model is SW6DE.

Thank you.

**Bill** · 03-03-2018, 09:28 PM

KK -

The water heater won't heat on the battery (12 VDC) source. You are misinterpreting the diagram. The heater does require a small amount of DC power to run the igniter and the controller for the gas section of the heater, but it won't heat on 12 VDC. Heat comes only from propane, or AC power.

The switch you are referring to is the switch on the kitchen sink apron, right alongside the red light. This switch controls gas operation, and has nothing to do with electric (120 VAC) operation. Many folks get confused by this. This switch brings power to the controller and igniter, but that is all. The electric (120 VAC) part of the heater has its own switch accessible from outdoors.

When you turn on the switch on the sink apron, the red light beside it will come on. This light indicates that the propane burner is trying to light - in other words, the gas valve is on and the igniter is sparking. As soon as the gas flame lights up, the igniter will stop sparking, and the red light will go off. Or, if the flame fails to light after a few seconds, the gas valve and the igniter will go off for a short interval, and then try again. It will try three times, and then shut off completely.

If you turned off the circuit breaker for the electric element, and you still got warm water, then it must have been heated by propane. This suggests that the propane did, in fact, come on for at least a short time, and then turned off and did not relight. There are a number of problems that plague the gas burner, such as rust in the burner, a misplaced thermocouple, low gas pressure or no gas, or spiders or silt in the burner. There are a number of threads here on the forum regarding how to service the gas burner. I'll try tomorrow to post a link here - or perhaps someone else will - regarding these threads.

Bill

K Kumar · 03-04-2018, 07:17 AM

Bill,

Thanks for the input & explanation. I get it.

The switch under the sink for the water heater is off. The 110V a/c switch outside is off. The circuit breaker for the heater is off.

So, how is the water heating up then? If it is heating on propane, I should be able to see the flame from outside, which I don't.

I am really puzzled.

tentcamper · 03-04-2018, 07:17 AM

you do need a certain voltage. what is the voltage of the battery when this happens?

**Bill** · 03-04-2018, 09:42 AM

With everything off (gas and electric), it is hard to imagine how the water got warm. My best guess is that 24 hours ago, or even 48 hours ago, the switch on the sink apron was ON, the propane supply was on, the flame lit, and the water heated. Then, at some point, you turned off the switch on the sink apron. Since the propane heater could no longer operate, the water in the heater gradually cooled, and you are now seeing the residual warmth. The water heater is very well insulated, and the temperature setting is very high, so the residual warmth would last a long time.

Does any of this ring a bell?

As an experiment, can you open a faucet and run the water until all of the warm water is gone and you are getting cold water out of the hot water tap. Make sure that all the switches are OFF, as you described above, and go away for 12 hours. When you come back, is there any warmth in the water?

Bill