Hot Water Tank - AC Operation

MadMax · 08-07-2012, 12:55 PM

I have a 2008 Cougar 238BHS fifth wheel with AC / Propane hot water heater. The propane option works fine. The AC option doesn't appear to be working. The element measures approx. 8 ohms and is not shorted to ground. there is 120 volts on the line coming to the element (when the AC switch is turned on). Can anyone suggest what might be the problem?

**hankpage** · 08-07-2012, 01:07 PM

The element with both wires removed should read 12-13 ohms. If you have voltage to it and it does not work replace it. You can save some money buying the element at a plumbing supply or "BIG BOX" store like Home Depot or Lowes instead of a rv dealer. Just be sure to match voltage and watts.

MadMax · 08-07-2012, 01:31 PM

Thanks Hankpage, you've come through again. I will do that.

MadMax · 08-07-2012, 06:52 PM

Hello hankpage,
I installed a new heating element, filled the tank with water (no air) and turned the AC switch on. After 40 minutes - still not even warm water. Would you have any other suggestions?
My next step was to try to wring out the wiring to see if the neutral line is actually hooked up at the electrical panel; as I mentioned earlier I do have 120 volts on one line coming to the element (black wire) but of course don't know if the neutral (white) is actually getting back to the panel.

chuck&gail · 08-07-2012, 08:00 PM

Connect the wires from the element to a 100 watt light bulb and see what happens. That is the simple way. I will NOT point out that alligator clips work fine if bulb is in a ceramic type socket.

MadMax · 08-08-2012, 04:34 AM

chuck&gail ,
Thanks for the tip. I'll give it a try. But it will have to wait for later; the way it's raining outside my 5er may have to double as an ark.

**JRTJH** · 08-08-2012, 07:09 AM

Madmax,

Just a reminder, there are two black round plastic "covers" in the upper left hand corner of your hot water heater (outside under the panel) that are actually "reset" buttons. If you haven't pushed them to reset the 110 volt circuit, it may not come on. Chances are, if you shorted out (or overheated) your original element, you also "popped" the reset......

I'd at least try that before you go tearing into it again.....

And, just to point it out, a electric test probe is really nothing more than a light bulb with an alligator clip on one end and a sharp point on the other.... pretty much the same as a light bulb and two wires.....

Good Luck

MadMax · 08-08-2012, 08:07 AM

Thanks JRTJH,

Yes, I understand about the light bulb thing. Earlier I did push the two Resets and they didn't move. I had removed the cover to see what the two resets looked like and they were two plastic tubes but, as I said, they appeared to be 'reset'.
I'll take the cover off it again and investigate further. I did check the continuity from the white wire at the element to the white wire in the electrical panel box inside and there is none. Do you know if this wire goes through the reset switches?

**JRTJH** · 08-08-2012, 02:48 PM

Here is a link to the suburban HWH service manual.

http://bryantrv.com/docs2/docs/subsw.pdf

On page 7 you'll find instructions on how to remove the door frame. (Don't do this unless you have to as you'll need to reseal the HWH to RV sidewall)

On page 10 you'll find the wiring diagram. The thermostat is also the reset assembly. It's accessible from the back of the door frame assembly.

On page 18 you'll find a drawing of the thermostat with the reset switch.

On page 23 you'll find the troubleshooting logic block guide for electrical operation.

Your problem is in the wiring/thermostat if the replacement heating element is installed correctly and is known to be good.

This may seem "elementary" but are you aware that the 110V switch in the lower left corner behind the burner tube is actually installed "upside down" and you push the top to turn the heater off and the bottom to turn the heater on? Just thought that is easy to miss if you don't actually look at the labels on the switch....

To answer your question about the wiring, the black wire comes from the circuit breaker panel to the connection block on the HWH, from there it goes to the on/off switch, then to the thermostat/reset switch, then to the heating element. The other connection on the heating element is the white wire, which goes back to the connection block on the HWH and from there back to the neutral bus bar on the circuit breaker panel. There may be some intermediate connections in your RV wiring, but probably not. There is also a ground wire (probabll bare) that goes from your HWH back to the ground bus on the circuit breaker panel.

The HWH connection block is inside your RV, on the back of the HWH

DONT FORGET TO DISCONNECT SHORE POWER BEFORE TOUCHING ANYTHING BEHIND THE CIRCUIT BREAKER PANEL !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Good luck and I hope this helps some

John

MadMax · 08-08-2012, 03:08 PM

John,
thank you for such a thorough reply. I was debating whether or not to remove the HWH panel to get in behind but realize that I would need to reseal it later. I am thinking it is a lot of work for something I really don't actually require. I am happy with the propane option. However, because it isn't just 100 %, I would still like to tackle and fix the problem, maybe at a later date; the trailer is only 4 years old and everything else seems to be working.
I will go to the pages you suggested and download the information. I would like to see the wiring diagram.
Many thanks John for your help and to all the others that assisted as well.
Don.

**hankpage** · 08-08-2012, 03:14 PM

John, Don said he had 110v at the element. If this is so the thermostat should be good and the problem lies in the neutral wire connection somewhere. The junction box on the rear of my WH is accessible through my cabinets, his might be also and worth a try. (tight fit but doable if not old and fat like me

)

**JRTJH** · 08-08-2012, 03:24 PM

My pleasure, Don. Like you, if it doesn't work, it bugs me until I either fix it or tear it up and have to replace it LOL Good luck

**JRTJH** · 08-08-2012, 03:31 PM

Quote:

Originally Posted by hankpage

John, Don said he had 110v at the element. If this is so the thermostat should be good and the problem lies in the neutral wire connection somewhere. The junction box on the rear of my WH is accessible through my cabinets, his might be also and worth a try. (tight fit but doable if not old and fat like me

)

That's correct, Hank. The white wire from the heater element goes to that junction block on the back of the HWH and then to the circuit breaker neutral bus bar.

I didn't want to start speculating and jump some of the basic steps in the troubleshooting guide. I learned long ago in aircraft maintenance and also in "people maintenance" that a good evaluation of the problem starting at step one and moving logically through the system (the same way every time) made for much less frustration than skipping steps and after disassembling the unit, finding that it was simply unplugged

But like you, I'm guessing there's a problem in the neutral (white) wire, somewhere from the heating element back to the circuit breaker box, but probably in the HWH beind the door frame assembly and the connection block on the back of the heater. (That is, assuming all the screw connectors on the circuit breaker panel neutral bus bar are tight and making good contact.)

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