I have a 2008 Komfort TT with an LP only water heater with automatic spark ignition. It was working just fine, then all of a sudden it would not light. Only cold water from the tap. There is gas, but no voltage at the on switch. We are on shore power. Other 12 volt things work (lights, range hood) but not the water heater. There is no fuse in the control center labeled ‘water heater.’ Any help for hunting down the problem would be appreciated. Thanks!
I would measure between both switch contacts and ground. 12 volt on one. zero or close to it on the other.. OPEN SWITCH 12 on both Problem down line zero on both Problem UP line.
Home was where I park it. but alas the. 2005 Damon Intruder 377 Alas declared a total loss after a semi "nicked" it. Still have the radios Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times
Thank you, that’s very helpful. That’s the schematic I have from the service manual. Have to guess which is the + wire coming into the switch since it’s “field wired” with no color code. The unit seems to function fine now after no effort on my part! Do you have any idea where the power to the switch comes from, since there is no water heater circuit on the panel? Thanks everyone for pitching in to help. If it fails again I’ll be back.
Your panel should have a switch and a light. The red light will come on when you turn on the switch and turn off when the burner flame is verified. 12V is at the switch (+) and ground is at one of the two wires on the light (-).
2011 Ford F-150 EcoBoost SuperCab Max Tow, 2084# Payload, 11,300# Tow, Timbrens 2013 KZ Durango 2857
144Grayling wrote: Thanks. It’s testing the power at the switch that is the challenge. It’s on the kitchen wall. Not much exposed metal there.
Oops, sorry. Lost my concentration on that one! 😮
So when checking the switch, either use the Ohms function, with power off, or check across both tabs with power on and using the 20VDC function. If the switch is working, AND both thermodiscs are good, and with power on, you should get 12VDC on the switch when it is switched off, and 0VDC when it is on. I would switch to voltage when checking the thermodiscs.
Today is my personal best for most consecutive days alive.
144Grayling wrote: What’s a good ground in the interior of a travel trailer? Everything is plastic or fiberboard!
There is plenty of grounded metal in the water heater itself. Just firmly put the black prove into the metal that makes up the heater. There will be a green wire that has a screw in it, that is the actual ground for the water heater. It is right in front of you in the heater.
Today is my personal best for most consecutive days alive.
144Grayling wrote: Thanks for all the replies. It is a suburban SW6D. I got the service manual on line and it said to check the voltage across the switch terminals so that is what I did. (Meter in parallel with switch) Zero voltage. The manual says if no voltage to check the 12 volt power input to the switch but I’m not sure how to do that. If it were a car I’d just go to ground. Does that work on a trailer? I can unplug the wires and try that way but there is almost no slack in the wires and I’m afraid of losing them in the wall. There is no fuse in the control center for water heater. The switch is mounted to the wall so I have no idea where the wires come from or go to. The service manual schematic shows a positive wire coming into the switch and a wire out the other side to a junction box but I have no idea where those are in the trailer itself. Where could this circuit get its power if not from the control center? (Note there is also no fuse in the control center for the LP detector and it’s not getting 12 volts either.)
Weird. When I went to check on it this morning it was working! When before the red light did not come on at all, it did this morning, then of course it goes out when it starts. So I might have an intermittent failure situation. Again any suggestions would be appreciated.
Very similar to a car test. Keep the black lead on ground and use the red lead to verify presence of 12v at the switch. Both tabs with switch on. Then use the red lead to check the two thermodiscs located under the black foam cover. There are two in series. One is the thermostat that sets water temp, and the other it the "over temp" safety thermodisc. If you have the black lead grounded, you should get 12v at all four of the disc connectors. If you lose it, one of the discs is bad. This is, of course, when you have cold water and the heater is calling for heat.
Today is my personal best for most consecutive days alive.
wrong way to measure switch! You would use resistance scale between switch contacts. You need to check volts with black lead to ground, red lead to switch wire with meter set on 20 volts or close. Check all fuse with meter set to 20 volts, black lead to ground red lead to fuses. Check both sides of each fuse. Red light should come on until water heater lights then goes out. Will come back on if error. Red light is fed from circuit board blue wire.
Thanks for all the replies. It is a suburban SW6D. I got the service manual on line and it said to check the voltage across the switch terminals so that is what I did. (Meter in parallel with switch) Zero voltage. The manual says if no voltage to check the 12 volt power input to the switch but I’m not sure how to do that. If it were a car I’d just go to ground. Does that work on a trailer? I can unplug the wires and try that way but there is almost no slack in the wires and I’m afraid of losing them in the wall. There is no fuse in the control center for water heater. The switch is mounted to the wall so I have no idea where the wires come from or go to. The service manual schematic shows a positive wire coming into the switch and a wire out the other side to a junction box but I have no idea where those are in the trailer itself. Where could this circuit get its power if not from the control center? (Note there is also no fuse in the control center for the LP detector and it’s not getting 12 volts either.)
Weird. When I went to check on it this morning it was working! When before the red light did not come on at all, it did this morning, then of course it goes out when it starts. So I might have an intermittent failure situation. Again any suggestions would be appreciated.
BFL13 wrote: 2003 Komfort 5er had Suburban WH Had to replace that red light switch. ISTR it's wires went to a small white box with ? fuse? then wires to WH. Was a reset on the WH outside too
I forgot about the reset. I had to keep resetting the T-stat/thermal cut off until it finely decided to give up completely.
Easy way to check it is remove the cover and the two wires and check for continuity with a VOM.
