No Hot Water from Electric

[CharlesinGA]

Update - I was able to test the resistance at the electrical element. It seems to be OK, read about 10-11 ohms. When I turned on power to the WH, no voltage registered across the element. I started pulling the wires off the thermostat to ensure they were connected properly and ended up pulling the thermostat off before the wire would release. I'm going to replace the thermostat and thermal cut off kit before going any further. They look like they've been there for while, so a new set won't hurt. Then I'll pick up with the troubleshooting at that point.

That is a relay inside the cover, which turns off and on the 120V AC and is operated by the yellow wire 12v DC from the control module.

When reassembled you should be able to switch on the electric switch and after a couple of seconds hear a distinct (but not very loud) click, of the relay. In my trailer the water heater is behind and below the dinette seat and a storage compartment on top of it, and when I am standing about 5 ft away, and switch on the electric switch, I can hear a distinct click.

Charles

 

[Rene T]

That is a relay inside the cover, which turns off and on the 120V AC and is operated by the yellow wire 12v DC from the control module.

When reassembled you should be able to switch on the electric switch and after a couple of seconds hear a distinct (but not very loud) click, of the relay. In my trailer the water heater is behind and below the dinette seat and a storage compartment on top of it, and when I am standing about 5 ft away, and switch on the electric switch, I can hear a distinct click.

Charles

Before you do this, make sure the tank is full.

 

[DaleandKarla]

That is a relay inside the cover, which turns off and on the 120V AC and is operated by the yellow wire 12v DC from the control module.

When reassembled you should be able to switch on the electric switch and after a couple of seconds hear a distinct (but not very loud) click, of the relay. In my trailer the water heater is behind and below the dinette seat and a storage compartment on top of it, and when I am standing about 5 ft away, and switch on the electric switch, I can hear a distinct click.

Charles

Thanks Charles - so the relay inside the cover could be bad? I would know that if I didn't hear the click from the relay? Could it also be a faulty control module?

 

[CharlesinGA]

Truthfully, I'd start at the circuit breaker, probe between the terminal on it and neutral, should have power, if not, you got a breaker problem. Skip the EMS for the moment and find the black wire going into the relay at the back of the water heater, probe between it and the white neutral (or the ground if it is easier), If you have power, THEN have someone turn on the switch while you listen for the click of the relay. If it clicks, then check for voltage across the heat element terminals.. (since it is 12v operated, it will click even if there is no 120v AC power available)..... Backing up, if you don't have power going into the relay, then the EMS is suspect, it has several relays in it, the one for the water heater could be bad, or have a loose connection, or the EMS could be shedding the water heater load for some reason. Truthfully I don't know much about the EMS, I do know about simple load shed boxes as I installed one in my trailer (30 amp shore power) to separate the microwave and water heater)

You may find out something on the Winnebago Forum on here, about the EMS. If I had it in front of me, I could muddle thru it, but I don't know enough about it to suggest much more from here.

One last suggestion not related to this problem. Once you locate which wiring diagrams and plumbing drawings are the ones for your model and serial number, click on it and at the bottom of the list of drawings is "Complete Wiring Diagram Book XXXXX-XXX-XX" Click on this (assuming you are using a windows desktop or laptop, not sure what you would see on a Mac) and once it loads, find the down arrow in the upper right corner (next to the printer symbol), which is the download symbol. Down load it and save it to somewhere on your computer and then copy it to a blank thumb drive. Do the same with the plumbing diagrams, the water heater service manual and add manuals as you stumble into them on the net. Carry this with you in the coach and you will always have them, whether you are using them, or a mobile tech or RV repair facility is working on them, you will have them.

Oh, and the coach body parts manual is online also.

Go here and get all of the instructions I recently posted about how to access the manuals and drawings.

Links to plumbing and wiring diagrams have disappeared!

Thanks to cbeierl (Chris) for the head's up about the dead links. I'll email my Winnebago contact to find out what the heck is going on with the missing links. *Hopefully* it's a mistake and they aren't removed on purpose, having those available is a super bonus for the DIY types. I did check...

www.rvforum.net

Charles

 

[Rob&Deryl]

Before you do this, make sure the tank is full.

To be clear, the hot water heater tank.

 

[DaleandKarla]

Truthfully, I'd start at the circuit breaker, probe between the terminal on it and neutral, should have power, if not, you got a breaker problem. Skip the EMS for the moment and find the black wire going into the relay at the back of the water heater, probe between it and the white neutral (or the ground if it is easier), If you have power, THEN have someone turn on the switch while you listen for the click of the relay. If it clicks, then check for voltage across the heat element terminals.. (since it is 12v operated, it will click even if there is no 120v AC power available)..... Backing up, if you don't have power going into the relay, then the EMS is suspect, it has several relays in it, the one for the water heater could be bad, or have a loose connection, or the EMS could be shedding the water heater load for some reason. Truthfully I don't know much about the EMS, I do know about simple load shed boxes as I installed one in my trailer (30 amp shore power) to separate the microwave and water heater)

You may find out something on the Winnebago Forum on here, about the EMS. If I had it in front of me, I could muddle thru it, but I don't know enough about it to suggest much more from here.

One last suggestion not related to this problem. Once you locate which wiring diagrams and plumbing drawings are the ones for your model and serial number, click on it and at the bottom of the list of drawings is "Complete Wiring Diagram Book XXXXX-XXX-XX" Click on this (assuming you are using a windows desktop or laptop, not sure what you would see on a Mac) and once it loads, find the down arrow in the upper right corner (next to the printer symbol), which is the download symbol. Down load it and save it to somewhere on your computer and then copy it to a blank thumb drive. Do the same with the plumbing diagrams, the water heater service manual and add manuals as you stumble into them on the net. Carry this with you in the coach and you will always have them, whether you are using them, or a mobile tech or RV repair facility is working on them, you will have them.

Oh, and the coach body parts manual is online also.

Go here and get all of the instructions I recently posted about how to access the manuals and drawings.

Links to plumbing and wiring diagrams have disappeared!

Thanks to cbeierl (Chris) for the head's up about the dead links. I'll email my Winnebago contact to find out what the heck is going on with the missing links. *Hopefully* it's a mistake and they aren't removed on purpose, having those available is a super bonus for the DIY types. I did check...

www.rvforum.net

Charles

Thank you so much, Charles. I finally did manage to get it working. Your advice was very helpful. To be honest, I'm not sure exactly what fixed it. I did replace both thermostats and then investigated the wiring at the back of the HWH. The grounding wires had broken free of the HWH, so I regrounded those and it's worked fine ever since. I didn't think the grounding wires coming free would cause it to stop working. Not something you want of course, but didn't think it would stop if from functioning. Thanks again!

 

[Kirk]

Not something you want of course, but didn't think it would stop if from functioning.

The control circuitry of any RV water heater (most heat the cold water ) uses 12V power and it does require a good ground to the RV as there is no return wire. That very likely was the cause of your problems. Well done!

 

[CharlesinGA]

The control circuitry of any RV water heater (most heat the cold water ) uses 12V power and it does require a good ground to the RV as there is no return wire. That very likely was the cause of your problems. Well done!

This is correct. There is a Yellow 12v power wire from the control board to the relay at the back of the water heater, but like Kirk noted, it needs a ground and depends on the ground provided by the 120v circuit to complete the circuit.

Charles