Water heater not working & other 12v issues

[median]

I should add that the lights and refrigerator seem to be working normally since changing the 12 V power supply (no flickering).

 

[median]

All connections are capable of developing corrosion on the contact surfaces, whether slip-on, plug-in or screw.

@Rene T 's good suggestion is in hopes that ALL contact surfaces have been removed, cleaned and re-assembled.


Here's what I do when troubleshooting anything electrical on our MH and I'm sure I've saved myself from future issues by performing some of these steps as preventive maintenance as I troubleshoot.

1. Bring CRC contact cleaner and lubricant, meter and crimpers with you when troubleshooting.
2. Remove all the related plugs and screw terminals from their sockets, spray both plug and socket with CRC and then insert+remove about three times to help break any corrosion.
3. Remove fuses or relays/breakers from sockets and dowse their contacts and sockets with CRC.
4. Look for crimp-on connections and re-crimp them (or replace if you see green/oxidation of the wire).
5. Trace all ground wires to the ground block or chassis. Remove them, scrape any dirt or paint off, clean the contact and bolts and put it all together. If those grounds are simply fastened with self-tapping screws, remove the screws - scrape the paint and use a bolt to secure the new connection.

You may also apply dielectric grease to contacts to help shield against corrosion. Use it springly as a little goes a long way.

Hoping this helps you, if not for today's issue, then for some in the future.

Every connection was cleaned and checked

 

[median]

Since the problem shows in the lights, the refrigerator. and the water heater, why are you only looking at the water heater? Those items all get power from the 12V system so your problem very unlikely to be in the water heater. Have you monitored the voltage of the 12V system when the problem is taking place? It sounds like that voltage is changing.

That just depends on your skill level but if the issue is the 12V supply, that isn't going to change anything.

The 12V supply was changed and shows exactly 12V output.

The 12V from the water pump should have worked on the heater switch but it didn't.

 

[Domo]

Do you have propane?

Meanwhile, if you have no batteries you are a completely dependent upon shore power, even through the converter (which should be putting out 12.6 volts, not just 12.0 volts, as stated). Any dip/surge/brownout with the shore power will be seen inside the rig on all lights/circuits. Perhaps you have more than one issue and local power is confusing what's going on?

 

[OldWEB]

Is this your set-up? With a meter, you should confirm the positive and negative wires.

 

[median]

Do you have propane?

Meanwhile, if you have no batteries you are a completely dependent upon shore power, even through the converter (which should be putting out 12.6 volts, not just 12.0 volts, as stated). Any dip/surge/brownout with the shore power will be seen inside the rig on all lights/circuits. Perhaps you have more than one issue and local power is confusing what's going on?

Yes, we have propane.

I'll turn the voltage up to 12.6V.

Thanks

 

[median]

Is this your set-up? With a meter, you should confirm the positive and negative wires.

That's basically the setup. I have a meter and the service manual. What I don't have is 12V to the remote switch.

Temporarily diverting 12V from the water pump switch didn't have any effect.

 

[CharlesinGA]

If the switch has a light inside it, then it too has to have a ground. The water heater ground is usually taken to a close location and grounded. Combined Gas and Electric water heaters have a ground wire, but also have a 120v ground so you are usually assured of having a ground. The ground for the water heater may go all the way back to your panel. Really sounds like the ground is missing somewhere.

If you have a separate fault light that only indicates the flame didn't fire after three tries. A light in the switch itself merely indicates that the switch is on, if the wires are connected correctly.

Charles

 

[Rene T]

I'll turn the voltage up to 12.6V.

How are you going to do that?

 

[median]

If the switch has a light inside it, then it too has to have a ground. The water heater ground is usually taken to a close location and grounded. Combined Gas and Electric water heaters have a ground wire, but also have a 120v ground so you are usually assured of having a ground. The ground for the water heater may go all the way back to your panel. Really sounds like the ground is missing somewhere.

If you have a separate fault light that only indicates the flame didn't fire after three tries. A light in the switch itself merely indicates that the switch is on, if the wires are connected correctly.

Charles

Thanks Charles, I'll check ground near the panel and water heater. It's the gas only model btw

 

[median]

How are you going to do that?

The power supply I bought has a potentiometer to adjust the voltage, which I did.

 

[median]

It was the thermal cutout that was stopping it.

I pulled out the thermal cutout and checked continuity across it, which showed an open circuit.

Just to be sure, I pulled the connector from the control panel on the heater and inserted my meter probes into the brown and green terminals. I turned on the switch and touched the brown wire the thermocouple had been attached to to the thermostat on the heater.

Bingo! 12 beautiful volts at the connector.

Very many thanks to all for helping me work through this - it's much appreciated.

 

[Kirk]

Bingo! 12 beautiful volts at the connector.

So is everything working as it should now?

 

[median]

So is everything working as it should now?

I'm hoping it will be once I get a new thermocouple. Let's say I'm quietly confident.

 

[median]

Okay. I celebrated prematurely.

New thermocouple arrived today and I'm now getting 12 volts at the connector, but no lamp and no ignition.

Is there a way to test the control board?

Thanks

 

[John From Detroit]

Okay. I celebrated prematurely.

New thermocouple arrived today and I'm now getting 12 volts at the connector, but no lamp and no ignition.

Is there a way to test the control board?

Thanks

Some RV stores (Dealers) may have a test set.. Key word "May"

 

[uchu]

Okay. I celebrated prematurely.

New thermocouple arrived today and I'm now getting 12 volts at the connector, but no lamp and no ignition.

Is there a way to test the control board?

Thanks

This video may provide some useful information:

 

[Gary RV_Wizard]

If the thermal cutoff was triggered, the must have been flames outside of the burner tube, so there is a good possibility that other wires were damaged by the flames. I suggest testing every exposed wire or component in that area.

 

[Kirk]

New thermocouple arrived today

Like Gary, I'm not sure what you are replacing. If it is the top in the picture that would be the overheat thermostat, or the bottom is the cutoff that Gray mentions. If not one of these, then what?

 

[Gary RV_Wizard]

Yes, I was referencing the thermal cutoff which is part of the wire. The Thermostat & ECO (Emergency Cutoff) looks like the one n Kirk's upper photo. Either the thermal cutoff or the ECO will remove 12vpower to force an immediate shutdown. The ECO auto-resets after it cools down and the control board can be reactivated by powering off and back on; the thermal cutoff has to be replaced before the control board will restart..