12 GA Suburban Water Heater with KIB Controller not working on electric

[2psnapod2]

Has anyone had any luck troubleshooting the water heater with the KIB system with the water heater not working on electric?

 

[danemayer]

I think the KIB controller activates a 12V relay that closes the 120V AC circuit to the water heater. The AC power comes from the main circuit breaker panel. I think beginning in 2017, the relay is located at the water heater. I would expect to find it in the junction box on the front inside corner of the water heater.

With a Suburban Water Heater, it's fairly common to find failures at the small black rocker switch on the water heater exterior, and of course the heating element itself.

 

[wdk450]

I think the KIB controller activates a 12V relay that closes the 120V AC circuit to the water heater. The AC power comes from the main circuit breaker panel. I think beginning in 2017, the relay is located at the water heater. I would expect to find it in the junction box on the front inside corner of the water heater.

With a Suburban Water Heater, it's fairly common to find failures at the small black rocker switch on the water heater exterior, and of course the heating element itself.

Also, there have been problems with the wirenut power connections to the Romex supply power at the little metal box on the top rear of the heater.

An AC voltmeter can give you some answers. There is a troubleshooting guide and an AC electrical schematic in the Manuals section of our Library, found under the "Tools" tab at the top of any forum page.

 

[2psnapod2]

I think the KIB controller activates a 12V relay that closes the 120V AC circuit to the water heater. The AC power comes from the main circuit breaker panel. I think beginning in 2017, the relay is located at the water heater. I would expect to find it in the junction box on the front inside corner of the water heater.

With a Suburban Water Heater, it's fairly common to find failures at the small black rocker switch on the water heater exterior, and of course the heating element itself.

Thanks Dan for the help. I did see that on the manual in the HOM. I did disconnect some of the wiring and was wondering what exactly the box that is always attached to the Water Heater with a zip tie was? It then has 4 wires going somewhere. Wonder if anyone has any idea as to where they go?

 

[danemayer]

Thanks Dan for the help. I did see that on the manual in the HOM. I did disconnect some of the wiring and was wondering what exactly the box that is always attached to the Water Heater with a zip tie was? It then has 4 wires going somewhere. Wonder if anyone has any idea as to where they go?

The junction box connects the trailer 12V DC and 120V AC wires to those in the water heater.

On older rigs, where the interior switch for 120V operation was a wall-type switch, the 120V AC ran from the circuit breaker, through that switch, to the junction box. From there, the 120V hot wire goes to the secondary switch on the Suburaban, then to the ECO/Thermostat, then to the heating element, and back to the junction box neutral wire.

120V AC operation on Atwood water heaters was by way of a 12V DC switch that operated a relay which in turn passed the 120V AC to the water heater. I believe there's also a relay on the water heater control board that the control board uses to switch 120V on and off as the thermostat dictates.

Suburban units got a 12V DC switch and associated relay located on the water heater (in the junction box I think) in 2017. The 12V switch and relay was introduced earlier and the relay has been located in a number of places over the years. Most recently on the water heater.

The KIB board switches the 12V DC to the relay on the water heater.

On a Suburban, to troubleshoot, I would suggest first checking for power at the ECO/Thermostat and working backwards to the secondary switch, and then to the junction box. Ground lead of the meter should be on a known good ground.

 

[2psnapod2]

Dan, do you know where these 4 wires go? I have the older (2019) KIB system. I had unhooked them when I took my water heater out to fix the platform it was setting on. They used a couple of 2x4 pieces and a 3/8' of OSB to put it on, and it was caving in pretty bad. So I pulled the water heater out and reinforced the platform. I hooked them up the way I though was correct. But when I turn on the 12VDC switch that is on the KIB master control board, I get 115 Volts on the element.

 

[danemayer]

Dan, do you know where these 4 wires go? I have the older (2019) KIB system. I had unhooked them when I took my water heater out to fix the platform it was setting on. They used a couple of 2x4 pieces and a 3/8' of OSB to put it on, and it was caving in pretty bad. So I pulled the water heater out and reinforced the platform. I hooked them up the way I though was correct. But when I turn on the 12VDC switch that is on the KIB master control board, I get 115 Volts on the element.


View attachment 65166

Seems like maybe the wires labeled R and O are swapped. The wiring diagram shows R as providing 12V to the propane side and O sending 12V to the relay that connects 120V to the heating element (via secondary switch and ECO/Thermostat).